Embed Size (px)
Citation preview
WASTE DISPOSAL PLANFOR
HONG KONG
EXECUTIVE SUMMARY
Waste Arisings
Hong Kong's waste arisings currently amount tonearly 22,500 tonnes per day (t.p.d.) not including the49,000 rrr of excavated and dredged materials which aredumped at sea. The main components of these arisings arehousehold waste (approximately 4600 t.p.d.), industrialand commercial wastes (approximately l800 t.p.d.),construction waste (approximately 6500 t.p.d.), livestockwaste (approximately 2000 t.p.d.), water works sludges(approximately 4000 t.p.d.) and pulverised fuel ash(approximately 2600 t.p.d.).
Waste Collection
Wastes are collected and delivered to disposalsites "by the statutory collection authorities (the UrbanCouncil, the Regional Council and the Director ofEnvironmental Protection), by numerous private wastecollection contractors and, in the case of some industrialwaste, by "in house" labour. The collection authoritiescollect and deliver for disposal most household, somecommercial and most street wastes, some clinical waste andmost excremental waste. The remainder is handled by theprivate sector. Environmental problems, which aregenerated by both the public and private sector wastecollection systems, include odour, leachate spillage,dust, noise and littering. Existing controls over theoperations of private sector waste collectors andtransporters are fragmented and ineffective.
Waste Disposal
Most wastes are currently either incinerated atone of three government-operated incineration plants ordisposed of at one of five government-operated landfills.The old composting plant at Chai Wan now functions as atemporary bulk transfer facility for the transport ofpublicly-collected waste to landfill. Incineration plantsare reserved primarily for the destruction ofpublicly-collected household wastes. Privately-collectedwastes are disposed of at landfills. Dredged andexcavated materials are currently dumped at sea whilstmost livestock and chemical wastes are hosed down into thenearest water course (livestock waste) or poured down thenearest drain (chemical wastes). Waterworks sludges arecurrently discharged either to sea or to inlandwatercourses. Pulverised fuel ash is either recycled asbuilding materials or stored in specially constructedlagoons. Environmental problems at existing lan<±filtis *include inadequate gas and leachate control, anddifferential settlement. The main environmentalcaused by incinerators is air pollution*
- II -
Future Projections
Based on past trends and future projections it isanticipated that daily waste arisings in Hong Kong willcontinue to increase such that by the year 2001 they willamount to approximately 30,000 t.p.d. This figureincludes approximately 5&0 t.p.d. of sewage sludge whichwill result from planned expansion of the existing sewagetreatment capacity and 6550 t.p.d. of waterworks sludge.It also includes 4500 t.p.d. of pulverised fuel ash andfurnace bottom ash. However it does not include dredgedand excavated materials intended for marine dumping, andwastes diverted for disposal at public dumps.
The Strategy
The different types of wastes arising in HongKong require different methods of treatment and disposal.These methods are :
.(a) Dredged and excavated wastes should continue to
be dumped at sea in a controlled fashion.. ' • • • • - - ;f
(b) Sewage and waterworks sludges arising in areaswith easy access to deepwater frontage should bedumped at sea initially on an experimental basiswith a view to further extension if this method isfound environmentally satisfactory; sewagesludge should be stabilised before Such dumpingproceeds; waterworks sludge will requirethickening to effect economy of transportation.
(c) Waterworks sludges not arising in areas with easyaccess to deepwater frontage should be dischargedto coastal waters down long sea outfalls. This issubject to detailed assessment studies on a caseby case basis to ensure that no long term damageto the marine ecosystem is caused.
(d) Sewage sludge not arising in areas with easyaccess to deepwater frontage should be ewatered.and disposed of at landfill.
(e) Excremental waste should be disposed of at sewageworks or in limited quantities at landfill.
(f ) Livestock waste collected by the government shouldbe f stabilised and composted _grlor_t9 S2S2]^sS£ •As all wastes cannot be dealt with in this way,"alternatives which require further considerationare:
1} disposal at landfill after stabilisation;ii) disposal at sea after stabilisation; andiii) disposal at sewage works by digestion
with sewage sludge.
- Ill -
(g) Abattoir waste should be regrocessed as far aspracticable, and the non-r*e cTe"aSXe fractionshould be disposed of at landfill.
( h ) Animal carcas ses should be _des trpyed .j L—J-Lcremator. r'T :l
(i) Clinical waste should wherever possible beiji.cinerato rs; to cater, .. .
for the""was'te g^erated at hospitals, doctors f
surgeries and clinics where incinerationfacilities are not available or cannot meet airemission standards a central incinerator shouldbe constructed.
(j) Chemical wastes should wherever possible becodisposed at landfill. Those wastes for whichthis is not possible should be disposed of at a
1 (k) Radioactive waste should be stored, returned tosuppliers or otherwise disposed of in accordancewith the directions of the Radiation Board.
(1) Pulverised fuel ash and furnace bottom ash shouldbe sold for re-use or lagooned; there is also apossibility, requiring further investigation, thatthe materials could be used for reclamation andland restoration.
(m) All other wastes should be disposed of atlandfills, if necessary after treatment atexisting incinerators or at transfer stationswhich are being developed (see below).
The Municipal Waste Disposal Strategy
The municipal waste disposal strategy is designedto ensure the environmentally acceptable disposal of wastein the 'most cost efficient manner available. Landfillswill always be required to dispose of various wastes andthe residues from other waste treatment processes (such asIncinerator ash, unuseable construction waste and somechemical wastes) for which there are no acceptablealternative methods of disposal.
_Three very large „ landfill __ ites__are being..,. dey elopje d _ in _ remot QT^JBSSAs^. SJL JtJfcijLJi ^ The s e^ "
s o a _network_of _ refusei . ^in_t^ r" ' _ WasteTjfOTor dinary refu col .it "will then, becompacted , containerised and shipjged^ in, |)ul|c \\ tos f + the ,lan ril"§. """""TPKe^'ifrrsF ' t wo ' ' * t ransfer^" ¥lta*ibtis'' ' being^ ^ _,_( W ^«L be used principally td handlepublicly-collected wastes, but as additional capacity isavailable, it is intended that transfer stations will alsoeventually be able to handle privately-coXlected wastes.
- IV -
Refuse transfer stations coupled with the newlandfills will be a comparatively cheap and undoubtedlymore environmentally acceptable disposal option thanmaintaining the existingr* municipal v> incinerators.Environmental problems caused by the incinerators areexacerbated by the fact that they are located in denselypopulated urban areas. As alternative treatment anddisposal facilities become available, these incineratorswill therefore be phased out. Any new incinerator thatmay in future be developed will have to incorporate highlysophisticated pollution control equipment allied to awaste segregation and recycling facility, and they wouldbe located in remote areas.
N
NEW TERRITORIES
UEN MUNTSUEN WAN
ROAD TRANSFERBARGETRANSFER
© LANDFILLTRANSFERSTATION
The strategy for the management of municipal waste
- V -
Livestock & Chemical Waste Control
In order to treat livestock manure collectedunder the waste control programme a number of wasteconsolidation/composting plants are planned at variouslocations in the New Territories. A chemical wastetreatment centre is also planned at Tsing Yi to tie inwith a new regulatory programme for chemical wastedisposal.
Tentative Programme
Working to a planning horizon of 2001 and subjectto the availability of resources the programme for thedevelopment of new facilities and the closure of old onesis :
Year Event
1989 • Lai Chi Kok incinerator Station Bclosed down upon recommissioning ofStation A
1990 . Expansion of composting plant at NgauTarn Mel to 25 t.p.d* capacityRefuse transfer station commissionedin Kowloon BayLai Chi Kok incinerator Station A andJordan Valley landfill closed whenKowloon Bay transfer stationcommissioned
1991 * Chai Wan pulverisation plant closed- 92 down
Livestock waste consolidation sitecommissioned at Site A in north eastNew TerritoriesLivestock waste consolidation sitecommissioned in south west NewTerritoriesSludge disposal facility commissionedat Sha Tin for marine dumpingChemical waste treatment centreincorporating a Marpol receptionfacility commissioned at Tsing YiWENT landfill commissionedIsland East transfer stationcommissioned In Chai Wan
- . - . . . Kennedy Town incinerator closed downPillar Point Valley landfill closed
VI -
Year Event
1993 . Shuen Wan landfill closed upon- 94 commissioning of NENT landfill
Island West transfer stationcommissioned in Western districtTransfer station commissioned inYuen Long/Tuen MunTransfer station commissioned inSha TinLivestock waste consolidation sitecommissioned in north west NewTerritoriesLivestock waste consolidation sitecommissioned at Site B in north eastNew TerritoriesJunk Bay landfill closed uponcommissioning of SENT landfillCentralised incineration facility forclinical waste and animal carcassescommissioned.
1995 • Transfer stations commissioned inWest Kowloon, Tai Po and possibly
2001 North Point. Livestock waste consolidation site
commissioned in south east NewTerritoriesLivestock waste consolidation sitecommissioned in the Islands District
The Kwai Chung incinerator will be closed downafter the Kowloon West transfer station is commissioned.
Legislative Control
•'•'••Acceptable environmental standards must beapplied to both collection systems and waste treatment anddisposal facilities. A licensing system will beestablished as part of a scheme of control for thecollection and transportation of chemical and difficultwastes. The feasibility of establishing a licensingsystem for the control of the private collection ofhousehold and commercial wastes will also be studied. Toensure waste treatment and disposal facilities areoperated to an acceptable environmental standard, full usemust be made of the licensing provisions of section 16 ofthe Waste Disposal Ordinance (Cap. 35 ) which must beamended to bring within its ambit facilities operated bygovernment departments.
TABLE OF CONTENTS
Page No,
1. INTRODUCTION 1
2. PLANNING OBJECTIVES AND THE SCOPE 3
BACKGROUND 3
PLANNING OBJECTIVES 3
PLANNING HORIZON AND THE SCOPE 4
INSTITUTIONAL ARRANGEMENTS AND FACILITIES FORTHE COLLECTION AND DISPOSAL OF WASTE 5
DIVISION OF RESPONSIBILITIES 5
WASTE COLLECTION 5
COLLECTION AUTHORITIES 5
PRIVATE SECTOR 13
WASTE TREATMENT AND DISPOSAL 14
FINAL DISPOSAL FACILITIES 19
TREATMENT FACILITIES-INCINERATORS & TEMPORARY TRANSFER 20
FACILITY
MARINE DUMPING FACILITY 23
CO-DISPOSAL FACILITY 25
RADIOACTIVE WASTE DISPOSAL 26
PFA AND FBA DISPOSAL 26
4. PROPOSALS FOR IMPROVEMENT OF EXISTING ARRANGEMENTS 29
BACKGROUND 29
WASTE COLLECTION 29
Household and commercial wastes 29
(a) Public sector 29
(b) Private sector 31
Industrial and construction wastes 32
Clinical waste 33
Other -wastes 33
- i -
WASTE DISPOSAL
Page No.
34
Landfill 34
Incinerators and temporary transfer facility 38
Codisposal facility 39
Legislative controls 40
5. WASTE DISPOSAL STRATEGY 43
SOLID MUNICIPAL WASTES 43
Final disposal sites 45
Strategy evaluation to arrive at a least-cost
plan for waste disposal 49
Programme 51
CONSTRUCTION WASTES 54
DREDGED AND EXCAVATED WASTES 55
DIFFICULT WASTE 56
Sewage sludge and water works sludge 56
Livestock waste 59
Animal carcasses 60
CLINICAL WASTE 60
CHEMICAL WASTE 60
RADIOACTIVE WASTE 62
PFA & FBA 62
SUMMARY OF THE STRATEGY 63
6* THE WAY FORWARD 65
PLANNING BEYOND 2001 65
THE OPPORTUNITY TO MINIMIZE WASTE GENERATION 65
x THE OPPORTUNITY TO PROMOTE RESOURCE RECOVERY 66v""" *"**llll-li"*l"l'—"™"*glll""'l*l™ll*—"" ^
THE ROLE OF THE PRIVATE SECTOR 68
CHARGING POLICY 68
LEGISLATIVE CONTROL 69
- ii -
LIST OF APPENDICES
Page No,
APPENDIX A TYPES AND QUANTITIES OF CURRENT WASTE ARISINGS Al
WASTE TYPESHousehold waste
Street waste
Marine collected waste
C omme r c1a1 w a ste
Industrial waste
Construction waste
Dredged and excavated wastes
Difficult waste
Chemical waste
Clinical waste
Radioactive waste
Pulverised fuel ash (PFA) and furnance
bottom ash (FBA)
Secondary wastes
CURRENT WASTE ARISINGS
COMPOSITION OF HOUSEHOLD WASTE
GEOGRAPHICAL DISTRIBUTION OF WASTE ARISINGS
DELIVERED TO LAND-BASED FACILITIES
EXTENT OF WASTE RECYCLING
AlAl
Al
Al
A3
A3
A3
A3
A4
A5
A5
A5
A6
A6
A6
A7
All
All
APPENDIX B PROJECTED FUTUEE WASTE ARISINGS Bl
PUBLICLY-COLLECTED WASTE
PRIVATELY-COLLECTED MIXED WASTE
CONSTRUCTION WASTE
DREDGED AND EXCAVATED WASTES
DIFFICULT WASTE
Sewage sludge
Water works sludge
Sewage works screenings
'Excrementa1 waste
Bl
Bl
B3
B3
B3
B3
B5
B6
B6
- lii -
Page No,
Livestock wastes
Animal carcasses
Abattoir waste
Condemned food
CHEMICAL WASTE
CLINICAL WASTE
RADIOACTIVE WASTE
PULVERISED FUEL ASH (PFA) AND FURNACE BOTTOM
ASH (FBA)
PROJECTED TOTAL DISPOSAL REQUIREMENTSFOR
MUNICIPAL WASTE
CONTROL TOTAL FOR MUNICIPAL WASTE
GEOGRAPHICAL DISTRIBUTION OF FUTURE WASTE
ARISINGS
B6
B9
B9
B9
B9
Bll
fill
Bll
B13
B13
B16
APPENDIX C ENVIRONMENTAL PROBLEMS Cl
ENVIRONMENTAL PROBLEMS POSED BY EXISTING
COLLECTION ARRANGEMENTS
ENVIRONMENTAL PROBLEMS ASSOCIATED WITH
WASTE TREATMENT AND DISPOSAL FACILITIES
Landfills
(a) Odour
(b) Gas
(c) Leachate
(d) Differential settlement
Municipal incinerators
Chai Wan pulverisation plant
Cl
C3
C3
G3
C3
C4
C5
C5
C6
APPENDIX D EVALUATION OF ALTERNATIVE DISPOSAL OPTIONS Dl
MUNICIPAL WASTES
Treatment Methods
(a) Resource recovery
(b) Incineration
(c) Transfer
Dl
Dl
Dl
D3
D5
- iv -
Page No,
Disposal Methods D7
(a) Landfill D7
(b) Dumping at sea D7
(c) Discharge to coastal waters D8
DIFFICULT WASTES D8
Sewagesludge D9
Water works sludge DIG
Sewage treatment works screenings and grit DIG
Excrementa1 waste Dll
Livestock waste Dll
Condemned goods,abattoir waste and
animal carcasses D12
OTHER WASTES D13
Dredged and excavatedwastes D13
Clinical waste D13
Chemica1 wa s t e D14
Radioactive waste D15
PFA and FBA D15
APPENDIX E THE WASTE MANAGEMENT MODEL (WMM) El
APPENDIX F ESTIMATED CAPITAL AND RECUREENT
COSTS OF PROPOSED MAJOR WASTE
MANAGEMENT FACILITIES
Fl
Table 1
LIST OF TABLES
Waste intake (t.p.d.) at treatment anddisposal facilities in 1988
Page No,
17
Table 2 Operating characteristics of existing andfirm-planned final disposal facilities 20
Table 3 Operating characteristics of existing wastetreatment facilities 21
Table 4 Capacities and calculated life times of 11potential strategic landfills and twopotential incinerators 45
Table A.I Estimated arisings of waste types in 1988(tonnes/day unless otherwise indicated) A2
Table A.2 Estimated Current Arisings of Chemical Wastesin Hong Kong in 1988 A8
Table A,3 Export of Waste Materials (From 1986 to 1988) A14
Table B*l Projected future arisings of sewage sludge(tonnes per day) B5
Table B*2 Projected future arisings of water workssludge (tonnes per day) B5
Table B.3 Projected future arisings of septic tanksludge (tonnes per day; 47* d.s.) B6
Table B*4 Projected future arisings of livestockwastes requiring collection and disposal(tonnes per day; 15% d,s*) B8
Table B*5 Projected Arisings of Chemical Waste in1992 &. 1997 (Units in tpa) BIO
- vi
LIST OF FIGURES
Page No«
Fig. 1 Municipal waste arisings, processing and
disposal flow for 1988 6
Fig. 2 Location of existing waste treatment anddisposal facilities 15
Fig. 3 Location of spoil grounds for dumping ofdredged materials 24
Fig. 4 Quantities of waste by category in 1988and estimates for 2001 44
Fig. 5 Potential future solid waste disposalfacilities in Hong Kong under considerationin 1983 study 46
Fig. 6 Proposed location of future refuse transferstations and strategic landfills 52
Fig. 7 Location of proposed sludge dumping ground 57
Fig. 8 Location of proposed chemical waste treatment plant 61
Fig. A.I Waste Composition - Waste Collected in Urban Areaand New Territories 1988 A9
Fig. A.2 Composition of domestic solidwaste in a number of cities A10
Fig. A.3 Boundaries of waste arisings districts in Hong Kong A12
Fig. A.4 Distribution of 1988 waste arisings by district A13
Fig. B.I Forecast of publicly collectd waste B2
Fig. B.2 Forecast of privately collected waste B2
Fig. B.3 Forecast of construction waste B4
Fig. B.4 Quantities of dredged and excavated material dumpedbetween 1978 and 1988 inclusive B4
Fig. B.5 Projected total arisings of PFA and FBA B12
• ' - . : - ' " - : • - • - - - - v i i ~ • ' - '• ' ' ' ' . ' : :
Page No,
Fig. B*6 The combined annual arisings of waste asa function of GDP B14
Fig. B.7 Forecast of municipal waste arisings based B15on GDP growth
Fig, B,8 Projected future waste arisings by regionand by type B17
- viii -
LIST OF PLATES
Page No,
Plate 1 Waste disposal operation at Junk Bay landfill 16
Plate 2 Excavated material loaded onto a barge for 24delivery to reclamation sites. Only unsuitablematerials are disposed of by marine dumping
Plate 3 Lagoon used for the storage of PFA slurry at 27Tsang Tsui, West New Territories
Plate 4 Unloading of refuse from plastic wheeled bins 30(equipped with self closing lids) into arefuse collection vehicle
Plate 5 Automatic washing station at a refuse collection 30vehicle depot
Plate 6 Landfill gas monitoring at a purpose-built borehole 35
Plate 7 A low-rise building structure erected at the Gin 37Drinkers1 Bay landfill which is being restored inphases for passive recreation uses
Plate 8 Lai Chi Kok incinerator is scheduled to be closed 38down upon the full commissioning of Kowloon Baytransfer station in April 1990
Plate 9 Delivery of properly packaged asbestos waste to 39Junk Bay landfill for codisposal with municipalwaste
Plate 10 Artist's impression of the layout of Kowloon Bay 53transfer station
Plate 11 Schematic diagram of refuse transfer operation 53
Plate 12 Construction waste contains much useful materials 55such as timber and wood waste which should besegregated at source for reuse and recycling
Plate 13 Codisposal of dewatered sewage sludge at Shuen Wan 58landfill
Plate 14 Collection of dry muck-out livestock waste at the 59livestock waste collection point
Plate 15 PFA land reclamation trial at Siu Lang Shui 62
Plate 16 Baled waste paper intended for export to the 66neighbouring South-east Asian Countries
- ix -
- 1 -
CHAPTER 1 INTRODUCTION
The Waste Disposal Ordinance (Cap 354) requires the policy
Secretary, currently the Secretary for Planning, Environment and
Lands to prepare draft plans showing
a) the arrangements made or proposed to be made for the
collection and disposal of
i) all solid and semi-solid wastes other than
those which may be discharged into the
atmosphere as particulates or discharged into
water as solids suspended in effluents; and
ii) such other wastes, or classes of waste, as
may be prescribed; and
b) all existing and proposed waste .disposal sites and the
methods of waste disposal used or to be used at each site.
2* In preparing this plan the Secretary consulted the
Environmental Pollution Advisory Committee, the Urban Council and the
Regional Council. The draft plan was published for public comment
between 4 August and 18 September 1989,
3. The Governor in Council approved the plan on 12 December
1989.
CHAPTER 2 PLANNING OBJECTIVES AND THE SCOPE
BACKGROUND /
4. .Hong Kong is a rapdern c1 tywith a j>opu 1 ati onof 5.7
million, and has nearly two hundredthousandcommercialand
industrial establishments. Their daily activities generate a
substantial amount of municipal waste* togetherwith the booming
cons true t ion and reel araat ion act i yi ty, /I iye s. tock_ ...faralng_in_ the rura 1
areas» power generation and water and/waj5t_ewater treatment
operations, the total daily arisings of all kinds of waste amount to
nearly 88 thousand tonnes, around three-quarter of which is dredged
and excavated material associated with dredging and reclamation
activity (Appendix A)* The management of this large quantity of
wastes requires proper planning to ensure that there are adequate
collection and disposal arrangements, as well as to avoid adverse
environmental and public health consequences.
PLANNING OBJECTIVES
5. The principal objective of this plan, as specified in Part
II of the Waste Disposal Ordinance, is to describe the arrangements
made or proposed to be made for the collection and disposal of all
wastes falling within the ambit of the Ordinance, and to give details
of all existing and proposed waste disposal sites and disposal
methods* In doing this, consideration must be given not only to the
Government^ role in waste collection and disposal, but also to those
of -
(a) the Municipal Councils. These are by statute autonomous.
As waste collection authorities, they provide the great
majority of public waste collection services, and any plans
must enable them to provide such services in an efficient
and environmentally acceptable manner; and
(b) the private sector, which already provides a significant
variety of waste collection and disposal services. As with
the Municipal Councils, the private sector should be able
to develop efficient and environmentally acceptable
services.
PLAHNIHG HORIZON AND THE SCOPE
6. The planning horizon for this plan is 2001* The emphasis
is on arrangements for the collection and disposal of household,
commercial and industrial wastes, and the need to provide these
essential services in the face of the changing demands imposed by the
development of the community. The implementation of this plan is
subject to the availability of financial and manpower resources*
CHAPTER 3 INSTITUTIONAL ARRANGEMENTS AND FACILITIES FOR THECOLLECTION AND DISPOSAL OF WASTE
DIVISION OF RESPONSIBILITIES
7. As defined in the Waste Disposal Ordinance, the collection
authorities are the Urban Council and the Director of Environmental
Protection (DEP) in respect of the Urban Council area, and the
Regional Council and DEP in the Regional Council area. DEP is also
defined as the waste disposal authority for all classes of waste. In
discharging their duties and functions, the collection authorities
and the waste disposal authority are required to have regard to the
waste disposal plan.
WASTE COLLECTION
8. The collection of the bulk of Hong Kong's waste is carried
out either by the collection authorities or by private waste
collection and disposal contractors. Private waste collection and
disposal contractors provide a service completely independent of the
publicly-funded collection authorities wherever markets for such
services exist . They are also frequently engaged by government
departments to remove specific types of waste from facilities
operated by those departments* In some instances departments
themselves remove and dispose of wastes generated at facilities under
their control. Fig. 1 summarises the existing arrangement for the
collection and disposal of various types of waste. A more detailed
consideration of the arrangements for the collection of wastes is
best considered on an agency-by-agency rather than a type-by-type
basis.
COLLECTION AUTHORITIES
•9V " The majority of the waste collected jy_tlie_J[Irb_an. Council
*jjoljits (RCPs) under the Lr control. There are 309 RCPs in Hong Kong
and Kowloon and approximately 1970 in the New Territories operated by
the two Councils.
6 -
PUBLICLYCOLLECTED
WASTE
(4033 tpd)
PRIVATELYCOLLECTED
WASTE
(2373tpd)
CONSTRUCTIONWASTE
(6521 tpd)
Z
4S.PULVERISATION
PLANT
Site
Ash
MUNICIPALWASTE13187 tpd
82%
V
PulverisedWastes
V
LANDFILL
DIFFICULT + MARINECOLLECTED WASTE(260 tpd)
Sewage Sludge & Sewage
Works Screenings
Excrements!
Others
Note: This figure only shows those wastes which are collected for disposal atthe municipal waste disposal facilities (i.e. municipal incinerators,pulverisation plant'"or landfills).
Figure 1 Municipal waste arisings, collection anddisposal flow for 1988
Of the 309 RCPs in Hong Kong and Kowloon, 80 are within permanent,
purpose-built off-street buildings, 37 are temporary off-street
structures and 192 are ^temporary _on-_street: flimsy encJLpjsures. Of the
1970 in the New Territories and outlying islands approximately 650
are permanent, off-street structures and the remaining 1320 are
temporary off-street structures. Permanent RGPs are purpose-built
structures incorporating where §J2££oj?x
extract io
facilities. As suitable sites cannot always be made available by the
Government, temporary RCP's have to be provided for the convenience
of the public to deposit their refuse pending collection by the
Municipal Councils.
10. Broadly speaking, in areas where RCPs have been located, no
kerbside or door-to-door collection service is provided. Instead
local residents are required to deliver their wastes to the RCP
nearest to them to await collection by one of the refuse collection
vehicles (RCVs) operated by the executive arms of the two Councils
(ie: the Urban Services Department (USD) and the Regional Services
Department (RSD)). Permanent off-street RCPs are provided where
appropriate with an attendant and waste may be delivered to the RCP
within specified operating hours. The attendant is authorized to
reject waste not suitable for collection at a RCP. This system is
adopted to ensure that the wastes deposited are acceptable.
11. The majority of the wastes delivered to RCPs for collection
is household waste. However in the urban areas a sizeable proportion
of the waste may be classified as commercial as it is waste from
nearby shops, stalls, restaurants and offices. Such commercial waste
is accepted at a RCP provided it does not amount to more than 100
litres per day from each establishment. Amongst the household waste
delivered to RCPs is junk and bulky waste. Such wastes are only
accepted at major RCPs.
12. All RCPs are visited at least once a .day by a RCV,
wh ich piies a pr e de te,rmine d route according__to a Jixed schedule_.
When the vehicle is full the waste is hauled directly to a waste
treatment or disposal facility* J&CVs^range in size from 3 to 12
tonnes capacity and virtually all are JLapaJxLe. of compacting refuse as
it is collected. Volume reduction achieved by compaction ranges from
67% to 80%. Compaction capability usually extends to an ability to
crush and compact bulky household items such as furniture. Wherever
possible these items will be collected during the course of a normal
collection round. For bulky items that cannot be crushed (eg.
domestic electrical appliances such as fridges) a special collection
round has to be made with lorries*
13. Although collection from RCPs is the main mode of
collect-ion of household wastes by USD and RSD there are some
variations. In the Urban Council area, in areas of low density
housing, or in areas where it has not proved possible to locate an
RCP, a kerbside collection service is operated. Householders need
only deliver their waste in plastic bags to the kerbside from where
they are subsequently collected by a RCV at a predetermined time. In
the rural districts of the Regional Council area where the provision
of a properly constructed RCP is not justified, householders in the
area need only deliver their wastes in plastic bags to the refuse
bins provided at selected locations where the wastes are subsequently
collected by a RCV or the RSD special cleansing gang. In both the
Urban Council and Regional Council areas a block-to-block service is
provided within the curtilage of institutions and building complexes
constructed by both the public and private sector.
14. In addition to collecting waste from RCPs and housing
blocks, the USD/RSD also collects wastes from individual building
developments in accordance with the provisions laid down in the
Public Cleansing & Prevention of Nuisances Bylaws (Cap 132) by
agreement with the owner of the property and subject to such terms
and conditions as the two councils may think fit. The Building
(Refuse Storage Chambers and Chutes) Regulations 1984 stipulate,
among other things, the mandatory provision of refuse storage
chambers in new buildings (other than car parks, industrial
buildings, schools and churches) with an aggregate usable floor space2
of 1320M or more and the provision of vehicular access to a public2
RCV if the aggregate usable floor space is 13,200M or more in the
case of domestic and composite buildings. The corresponding criteria
for non-domestic buildings are 3960M and 39,600M respectively. The
UC was instrumental in introducing these regulations, which
effectively stopped the then ever-growing demand for more on-street
RCPs as building developers thereafter were to provide adequate
refuse storage space and vehicular access for public RCVs to collect
refuse within the curtilage of new building developments.
15* Special arrangements are made for the collection of wastes
on the outlying islands. On Lantau, in areas where there are
vehicular access roads, wastes which are delivered by householders in
plastic bags to RCPs and bin sites are collected by lorries, and most
of the waste is disposed of at the modular incinerator at Mui Wo.
The remaining wastes together with the bulky household items and
incinerator ashes are taken by a contracted barge service which also
transports refuse from Cheung Chau and Discovery Bay. The household
waste is taken to Kwai Chung incinerator and the bulky items are
taken to Pillar Point Valley landfill. A similar barge service is
also provided for Lamma and Peng Chau Islands. In isolated villages
on the islands, waste is presently disposed of by means of village
type incinerators which will be gradually phased out and replaced by
properly designed package type incinerators or by suitable collection
arrangements to the mainland.
16. In addition to the collection of household and commercial
waste as described above, the Urban Council and Regional Council also
provide services for the collection of
(/ Ca) street waste and litter, including beach litter;
,{/.''J(b)- carcasses of dead animals;
excremental waste; and
(d) clinical waste.
- 10 -
°r
mechanica 1 ly ) , empty Utter bins , and coUec J-ltjt ^
sweepings and litter are delivered to the nearest
refuse collection point and subsequently removed, along with other
wastes deposited there, by RCV and other transport. At those beaches
where vehicular access is difficult, the collected litter is disposed
of either by on-site burning or by burning in village type
incinerators. The litter collected from country parks : Jb j _the
J^sheries D§2artment:_ is also deliyejredjto ^
_RCP; for sub eflugnt jrjsmoya 1 by RCV, or to a barging point for
subsequent removal by a contract barge service.
18. The carcasses of dead dogs and cats left on the streets are
a special form of street waste. Animal carcasses, including dead
pigs and poultry, are collected by special USD or RSD removal gangs
using vehicles with a self-contained, steel-lined, rear compartment
allowing complete separation of the carcasses from the crew in the
driver's cab. They are then taken directly to a disposal facility.
19. The Urban Council and Regional Council provide collection
services for the following types of excrement a 1 waste -
(/ Oa) nightsoil; and
septic tank sludges.- ' ' ' ' '
20. A free nightsoil collection service is provided to premises
which have no flushing toilets. Most collection is carried out
manually but if vehicular access is possible mechanical collection
can be achieved using purpose-built tanker vehicles.
- 11 -
21. Pneumatic desludging of household septic tanks is carried
out on request but, unlike nightsoil, the service is not free of
charge. Charges are set to recover the cost of the service and the
latter is provided subject to the availability of vehicles and
manpower. Desludging of septic tanks installed at government
buildings (eg. public toilets) is carried out by USD and RSD.
Desludging of a few, large tanks (Imhoff tanks) is carried out by the
Electrical and Mechanical Services Department. Many private
households also rely on private contractors for desludging of septic
tanks.
22. A service for the collection of clinical waste is provided
by the Urban Council to those medical institutions which either do
not possess their own disposal facilities (usually in the form of
incinerators) or whose facilities are inadequate to the task. The
service is provided to both private and government establishments.
Most types of waste are collected and stored in black plastic bags
prior to removal to a designated collection point within the
institution. /Sharp objects such as syringe needles and scalpels are
first placed in cartons to reduce the danger of perforation of the-N,
bags and subsequent injury to personnel^.) The waste is collected in a
van similar to that used for animal carcasses and transported to a
disposal facility./ Amputated limbs and excised organs are placed in
boxes and collected in a special Mcemetary van11 prior to placement in
coffins and final disposal at Cape Collinson crematorium and the
Diamond Hill Crematorium. ;; 4 l
23. Notwithstanding the provision of a special collection
service some types of clinical waste are also mixed with ordinary
refuse and collected and removed during the normal USD or RSD refuse
collection* A 1982 survey of 74 government and private hospitals and
clinics revealed that( 15% of general ward waste was collected by the
special collection service but a similar amount of the same waste was
collected during the ordinary collection round. ) For theatre and
laboratory wastes the figures were 1270 collected by the special
collection service and 5% collected with ordinary refuse.
- 12 -
For maternity wastes the corresponding figures were 30% and 19%
respectively. Even amongst government hospitals there appears to be
a lack of consistency in the way the wastes are dealt with. For
example at Queen Mary Hospital, Tang Shiu Kin Hospital and Tsan Yuk
Hospital contaminated waste from treatment areas is removed by the
special collection service. Queen Mary Hospital and Tsan Yuk
Hospital also use the special collection service for the removal of
certain pharmaceutical and chemical wastes, but Kowloon Hospital and
Queen Elizabeth Hospital get rid of this waste via the normal refuse
collection service.
24, The survey of government and private hospitals and clinics
referred to above did not cover private doctors1 clinics and
surgeries. Waste generated at these clinics and surgeries is not
collected by a special collection service and inevitably finds its>-•••.•'
into £he ordinary cammer'cial refuse.
25. A limited collection service is provided for livestock
wastes through contractors employed by the Environmental Protection
Department. The collection service is intended mainly for the
collection of manure from dry muck-out and sludge arising from
treatment of wet muck out waste. Each collection point will consist
of a number of drums into which waste may be deposited.
26. The service is provided initially in the first few
livestock waste control areas such as the Tolo Harbour and Tolo
Channel Area and this will be. extended to tie in with the phased
implementation of the regulatory controls so that all livestock farms
have access to a collection point. Where road access is poor the
roads in question will be upgraded. Initially the waste will be
collected by a government contractor employed by the Environmental
Protection Department and delivered either to a landfill site or a
composting plant for disposal or treatment respectively.*
- 13 -
The cost of the collection service will initially be met by the
government but the subsidy will gradually be phased out so that it is
eventually borne by the farmers. It is possible that this will lead
to the eventual replacement of the government service by collection
arrangements organised by the farmers themselves.
PRIVATE SECTOR
27. Private waste collection and disposal enterprises in Hong
Kong are many and diverse. They range from individuals engaged by
householders in multi-storey buildings to collect refuse daily and °
deliver it to RCPs, to large modern waste disposal contractors who
collect industrial waste and deliver it to a final disposal point.
28. The private waste collection and disposal enterprises deal
with most types of waste generated in Hong Kong. Industrial wastes,
construction wastes, certain chemical wastes, pulverised fuel ash,
and condemned food are handled exclusively by the private sector.
Substantial amounts of commercial wastes are also collected by the
private sector. Household waste is collected mainly from those
private developments which do not have facilities and vehicular
access of the standard required by the collection authorities but for
which it would be impractical to send waste to a RCP.
29. Due to the diversity within the private sector it is
impossible toj nerali transportation
arrangements. Such arrangements are in any case worked out by
contracting parties. Suffice to say that a wide variety of
collection vehicles is employed, ranging from hand trolleys onto
which are loaded open baskets of waste, through general purpose vai«s
and trucks to purpose-built RCVs and tankers. Except in the case of
certain special types of waste (specifically certain categories of
dangerous goods defined in the Dangerous Goods Ordinance, Cap 295)
- 14 -
and notwithstanding provisions in the Public Cleansing and Prevention
of Nuisances Bylaws (Cap 132) which do offer some scope for control,
collection and transportation equipment and practices are seldomly
controlled. A measure of control is imposed in respect of those
specific collection services that the government contracts for.
These include the collection of sewage screenings and grit, sludges
from Imhoff tanks at government facilities, and secondary wastes.
Sewage works screenings and grit from screening plants operated by
the Electrical and Mechanical Services Department (EMSD) are
collected in 200 litre covered drums and removed by a contractor on a
flat bed lorry. Imhoff tanks in some government facilities are
desludged by EMSD and the sludge is also placed in 200 litre covered
drums which are removed on a flat-bed lorry by a private contractor.
Of the secondary wastes which comprise incinerator ash and pulverised
waste, incinerator ash is removed by EMSD in dumper trucks whereas
pulverised waste is removed from the Chai Wan pulverisation plant by
a contract barge service.
WASTE TREATMENT AND DISPOSAL
30. Excluding marine dumping sites there are nine major
facilities operated or controlled by the government at which waste is
treated or disposed of. These comprise five landfills, three
incinerators, and one temporary transfer facility (Chai Wan
pulverisation plant). Regionally, they are distributed as follows• :-
Hong Kong Island Kennedy Town Incinerator
Chai Wan Pulverisation Plant
•'•Kowlooii Lai Chi Kok Incinerator
Jordan Valley Landfill
New Territories Kwai Chung Incinerator
Junk Bay Stages I & II Landfills
Shuen Wan Landfill
Pillar Point Valley Landfill
The locations of these facilities are illustrated in Figure 2.
- 15 -
NGUANGDONG SHENG
JUNK BAY STAGE I
JUNK BAY STAGE
LEGEND:
A LANDFILL
• INCINERATOR
• PULVERISATIONPLANT
Figure 2 Location of existing waste treatment anddisposal facilities
31, A small modular incinerator (theoretical capacity 12
t.p.d.) at Mui Wo on Lantau Island is operated by EMSD to deal with
domestic refuse. A number of village-type incinerators are operated
by RSD in remote villages at the outlying islands for the destruction
of refuse* A new package type incinerator is also operated by RSD at
Kat 0 in North District. Other small incinerators are located at
hospitals for the destruction of clinical wastes, and at the Urban
Council abattoirs for the destruction of diseased animal remains.
The hospital and abattoir incinerators are designed for longer waste
residence times than municipal incinerators to ensure that complete
destruction of all combustible material is achieved.
- 16 -
Plate 1. Waste disposal operation at Junk Bay Landfill
32r. Most wastes are currently disposed of or treated at one of
the above nine major facilities. The manner in which wastes were
distributed amongst the different facilities in 1988, by broad type
and collecting agency, is set out in Table 1. The three
incinerators, Chai Wan pulverisation plant and Jordan Valley landfill
mainly receive waste collected by the collection authorities, the
bulk of which is household waste. Around six per cent of the waste
delivered to Kennedy Town and Lai Chi Kok incinerators is waste of a
commercial nature delivered by the private sector. Such deliveries
are made under a permit system. The purpose is to provide these
incinerators with a certain quantity of high calorific value waste
which, when mixed with domestic waste, helps produce a better burn
and thereby increases operating efficiency. For Kwai Chung
incinerator the intake of commercial waste is unnecessary.
- 17 -
Table 1. Waste intake (t.p*d.) at treatment and disposalfacilities in 1988
WasteFacility
Kennedy Town0 incineratorxLai Chi Kokincinerator
Kwai Chung, incineratorChai Wanpulverisationplant
Pillar PointValley landfill
Shuen Wanlandfill
Junk Bay Stage I5 landfillJunk Bay StageII landfill
Jordan Valleylandfill
^•Publiclycollected
500
443
861
490
375
419
245
700
Privately-collected
Industrial,Commercial,Household
76
22
425
253
1520
1747
10
Construc-tion
960
1157
4019
2373
294
Publicly-collected orcollected under contract
Difficultclinicalandmarine
28
125
106
1
Inciner-ator ash
208
262
130
Pulverisedwaste
374
Total
576
465
861
490
1996
1954
6526
4250
1005
Collected by USD and RSD; mainly household waste but including somecommercial and street waste.
Includes sewage screenings and sludge, excremental waste, condemned food,abattoir waste, clinical waste, and marine collected waste*
Plant A closed temporarily from Feb 1987 to Mar 1989 for retro-fitting withelectrostatic precipitators and hence the intake has reduced.
Chai Wan pulverisation plant was originally a composting plant which ceased toproduce compost in August 1987. It is now used as a temporary transfer facility.The total intake also includes waste by-passing the plant and directly off-loadedfor barge transfer to Junk Bay landfill.
Junk Bay Stage II landfill commenced operation for a short period of 2 weekstowards the end of 1988, and the waste intake figures relate to this period .
-. 18 -
33. The pattern of delivery of publicly-collected waste to the
incinerators, the pulverisation plant, and Jordan Valley landfill is
based primarily on the need to keep the transportation costs of the
collection authorities as low as possible. Thus Chai Wan
pulverisation plant receives the bulk of its intake from Eastern
district and Wan Chai whereas the main intakes for Kennedy Town
incinerator are from Central & Western and Southern districts.
Similarly in Kowloon, Lai Chi Kok incinerator obtains the bulk of its
intake from Kwun Tong, Wong Tai Sin, Kowloon City and Tsim Sha Tsui.
Kwai Chung incinerator takes large quantities from Kwai Chung and
Tsuen Wan, and it also takes substantial amounts from Sham Shui Po,
Mong Kok and Tsim Sha Tsui. The bulk of the publicly- collected
waste delivered to Jordan Valley landfill originates in Kwun Tong but
substantial quantities also come from every other district in
Kowloon.
34. As far as publicly-collected wastes are concerned the
remaining facilities are strategically located and serve easily
identified catchment areas in the New Territories. Thus Shuen Wan
landfill serves the north east New Territories and receives
publicly-collected waste arising in Sha Tin, Tai Po and North
districts. Pillar Point Valley landfill serves the western New
Territories and receives almost all its publicly-collected waste from
Tuen Mun and Yuen Long-* Junk Bay landfill (Stages I & II) serves the
south east New Territories and receives the majority of its publicly-
collected waste from Sai Kung.
35* Over 95% of all the waste collected by the private
sector is delivered to the four landfills in the New Territories*
Junk Bay landfill (Stages 1 & II) is the main destination for
privately-collected waste arising in Hong Kong and Kowloon but both
Shuen Wan and Pillar Point Valley take in small quantities from these
regions. Privately-collected wastes arising in the New Territories
- 19 -
are distributed to landfills mainly according to the catchment areas
in which they arise, but in addition to taking waste arising in the
south-east New Territories Junk Bay landfill (Stages I & II) also
receives a substantial amount of its privately- collected wastes from
Kwai Chung and Tsuen ¥an.
FINAL DISPOSAL FACILITIES
36. The final disposal facilities are the landfills. They are
operated by private contractors under the control of the Civil
Engineering Services Department* ...WasJbedellye
and compacted in layers.. Compact ion is achieved by using special
steel-wheeledcompactorvehicles which move to and fro acrossthe
surface of the refuse.The exposedsurface of thewaste iscovered—•-•• • ' ' iff"at the end of the working day^y a layer of fill (usually excavated
material). This helps to reduce nuisance and improve the visual
impact of the operation.
37. The characteristics of the five existing landfills, are
given in Table 2. The unit operating costs (which exclude the costs
of transportation, occasional capital works and terminal works) range
from $30/tonne to $60/tonne. The landfills at Shuen Wan and Junk Bay
Stages I/II are marine sites. That is, they have been constructed
next to the shore line. At these sites refuse is effectively being
used to reclaim parts of the sea bed and foreshore.
38. Although there is no indication in Table 2 of a maximum
operating capacity there is nevertheless a limit to the quantity of
waste that can be accepted each day. This limit is determined by the
capacity of the surrounding road network to cope with the RCV
traffic, the layout of the tipping area, and the capacity of site
equipment and machinery. None of the existing landfills is operating
at maximum capacity and the maximum operating limits have not yet
been tested.
- 20 -
Table 2. Operating characteristics of existing and committed finaldisposal facilities
Facility
Pillar Point Valley landfill(inclusive of extension)
Shuen Wan landfill(inclusive of extension)
Junk Bay Stage I landfill
Jordan Valley landfill
Junk Bay Stage II landfill
Junk Bay Stage III landfill
West New Territorieslandfill
North East New Territorieslandfill
Datecommissioned
/to becommissioned
1983
1974
1979
1986
1988
1992
1991
1994
Capacity(m. tonne)
5.3
7.0
10.0
1.0
5.0
7.0
57.0
37.0
Intakerate
in 1988(t.p.d.)
1996
1954
6526
1005
4250
n. app.
n. app.
n. app.
Remainingcapacity(m. tonnes)(as atNov '88)
3.64
2.00
1.57
0.51
5.0
7.0
57.0
37.0
NB ; n- app.m. tonnes
not applicable;million tonnes; t«p*d. = tonnes per day-
TREATMENT FACILITIES ~ INCINERATORS & TEMPORARY TRANSFER FACILITY
39* The three incinerator plants take in combustible waste and
reduce it to 21 to 28% of its original weight and 5 - Tl» of its
original volume by burning it. Bulky wastes, such as household
furniture, are shredded prior to loading in the furnaces*
- 21 -
40. Statistics relating to the operation of the incinerators
are presented in Table 3. The normal operating capacity of all three
plants combined is 2550 tonnes per day (t.p.d.). However Plant A at
Lai Chi Kok incinerator has been closed down while electrostatic
precipitators are installed. Hence operating capacity of the three
incinerators is now therefore only about 2000 t.p.d.
Table 3. Operating characteristics of existing waste treatment facilities
Facility
Kennedy Town incinerator
Lai Chi Kok incinerator
2 Station A
Station B
Kwai Chung incinerator
Chai Wan^pulverisationplant
Datecommissioned
1967
1969
1974
1978
1979
Throughputcapacity(t.p.d.)
650
550
450
900
480
Intakerate
in 1988(t.p.d.)
576
/
465
861
380
•r/*secondarywastes( byweight)
28
/
21
25
-
Operatingcost
($/ tonne)
112
)) 159)
100
94
Includes depreciation of vehicles, equipment, buildings and plant,cost of transportation and disposal of ash and cost of bargingpulverised waste to landfill but excludes all capital costs andcosts of transportation of waste to facilities and cost ofdisposal of pulverised waste at landfill.
Station A is closed for retro-fitting with electrostaticprecipitators and the operating cost is based on both stations inoperation, and includes the importation of electricity during thisperiod.
Chai Wan pulverisation plant was originally a composting plant whichceased to produce compost in August 1987 * It had an originalprocessing capacity of 480 tpd. The waste intake figure does notinclude waste by-passing the plant for direct off-Loading -to thebarge for transfer to Junk Bay landfill.
- 22 -
41. The incineration process is essentially self-sustaining,
with refuse used as fuel. However for start-up ignition it is
necessary to use fuel, oil. Additional quantities of fuel oil may
also have to be burned from time to time to assist the combustion
process, especially during the rainy season when the refuse is
particularly wet. The older incinerators at Kennedy Town and Lai Chi
Kok use significantly more fuel oil than that at Kwai Chung.
42. The Kwai Chung and Kennedy Town incinerators have the
capacity to recover energy from the refuse, as does Station A of the
Lai Chi Kok incinerator. Energy recovery is effected by the
conversion, in a boiler, of waste heat to steam and the use of the
steam to drive a turbine. In this way Kwai Chung incinerator
produces sufficient energy for its own needs and could export
electricity if a suitable recipient were located nearby. Station A
at Lai Chi Kok normally produces sufficient electricity to run the
whole plant (i.e. Stations A and B). Kennedy Town incinerator
produces sufficient steam to generate power for the whole plant.
Work was completed to modify the electricity supply system to make
full use of the available power. Surplus steam is also available for
export to the abattoir next door. Other resource recovery is limited
to the magnetic separation of ferrous metals from the incinerator
ash. However it has not been possible to find a commercial outlet
for the recovered product and hence utilization of the magnetic
separation unit is low.
43. The Ghai Wan pulverisation plant was originally a
composting plant designed to treat principally organic refuse so that
as much of the refuse as possible could be converted to compost by a
controlled process of biological degradation. When operating
normally degradation took place in enclosed fermentation chambers
where the refuse was held for approximately 72 hours. Prior to
entering these chambers the refuse was pulverised and screened to
obtain the desired particle size, and ferrous metals were removed by
magnetic separation. After fermentation, the compost went through a
further screening and separation process during which much unwanted
material, such as plastics and glass, was removed.
- 23 -
44. The plant had a designed process capacity of 480 tonnes per
day which could in theory produce 160 tonnes of compost, the
difference being due mainly to rejected material which would have to
be disposed of at a landfill, and a certain amount of moisture loss.
In practice the maximum throughput that could be achieved was 360
tonnes per day* At this rate the theoretical maximum rate of compost
production would be about 120 tonnes per day but this has never been
achieved simply because it has not proved possible to find a market
for the product. Although efforts were made in the past to ensure
the plant received mainly organic refuse (for example by requiring
RGVs serving markets to travel to Chai Wan to offload) the compost
produced was nevertheless of rather poor quality, consisting of a
considerable amount of granular particles of glass and plastics. The
poor quality, in particular, the heavy metal content which rendered
the product unsuitable for agricultural use, is thought to have been
a contributory factor in limiting demand. As a result of the poor
demand the only users of the produce were USD and RSD who used it for
landscaping purposes. Their requirement was for only approximately
10 t.p.d., or one sixteenth of the plant's capacity. Because of the
low demand compost production has now ceased completely and the
refuse is now simply pulverised then transferred by barge to the Junk
Bay Stage II landfill* The plant therefore acts as a simple transfer
facility.
MARINE PIMPING FACILITY
45. Dredged material is not suitable for disposal in
public dumps and since it is marine in origin the logical place
to dispose of it is in the sea. Dredged material may be
disposed of.at one of the three spoil grounds whose locations
are illustrated in Figure 3. Excavated muds and other soils not
suitable for disposal either at public dumps or at landfills are
also dumped at sea. Dumping at sea may be carried out only under the
terms and conditions of a licence issued by the Director of
Environmental Protection under the Dumping at Sea Act 1974 (Overseas
Territories) Order 1975.
- 24 -
GUANGDONG SHENG
gj Spoil Ground
r-~i Spoil GroundL..J (new alignment)
Figure 3 Location of spoil grounds for dumping ofdredged and excavated materials
Plate 2. Excavated material loaded onto a barge for delivery toreclamation sites. Only unsuitable materials aredisposed of by marine dumping
- 25 -
46. The potential environmental effects of the dumping of
dredged and excavated wastes at sea vary according to the nature of
the material dumped. For example soils dredged from polluted areas
such as typhoon shelters or those areas which receive substantial
discharges from land-based sources (e.g. Kai Tak nullah) may exert a
heavy oxygen demand on the waters into which they are dumped, and
introduce substantial amounts of persistent pollutants such as heavy
metals into the area of the dumping ground. However most of the
soils dumped at sea in Hong Kong are relatively clean and adverse
effects tend to be limited to the smothering effect on the sea bed.
The water quality at the three existing dumping sites is monitored
and the dumping appears to have had little or no effect upon either
the concentration of dissolved oxygen or water turbidity.
CO-DISPOSAL FACILITY
47. The majority of chemical wastes are now simply poured down
the nearest drain. For certain chemical wastes disposed of at
landfill there exists a voluntary system of control. If a waste
producer is in possession of a waste which he believes may be toxic
or hazardous he can contact the Environmental Protection Department
(EPD) for advice as to how to deal with it. Provided EPD is supplied
with sufficient information the waste producer will be advised as to
how and where the waste may be safely disposed of. If the waste is
suitable for codisposal, a permit will be issued to the waste
producer for taking the waste to the landfill at Junk Bay where it
will be buried or co-disposed with municipal waste in a manner
designed to ensure its eventual detoxification and/or neutralisation.
The types of chemical waste currently disposed of at Junk Bay
Landfill include asbestos, oily sludge, tannery off-cuts, oil-water
emulsions and inorganic compounds. In future, Pillar Point Valley
Landfill will also be used for the codisposal of asbestos waste, but
other existing landfills will not be considered for the codisposal of
chemical wastes other than asbestos.
- 26 -
RADIOACTIVE WASTE DISPOSAL
48. A variety of radioactive wastes are generated in Hong Kong.
The disposal of radioactive wastes is governed by the Radiation
Board, a statutory body established under the Radiation Ordinance
(Cap. 303). Since wastes which consist of sealed sources are
returned to the suppliers of those sources, the main concern is with
unsealed wastes. Some low level wastes (mainly from clinical
laboratories) are permitted to be disposed of as ordinary refuse and
sent to a refuse collection point in a thick thermal sealed bag. A
limit, which depends on the precise type of radioactive species in
question, is imposed on the amount of waste that can be disposed of
by this route each month. Other types of radioactive wastes are
either returned to the suppliers, encased or sealed for storage in an
underground chamber, or destroyed at designated incinerators or the
Kennedy Town Incinerator if the waste is suitable for combustion.
PFA AND FBA DISPOSAL
49. Although technically wastes, pulverised fuel ash (PFA) and
furnace bottom ash (FBA) are in fact products of some value. Upto
now Hong Kong Electric has been able to dispose of its PFA and FBA by
selling-the materials to two companies for use as a cement additive
and for use in the manufacture of cement blocks. China Light and
Power is also able to sell a proportion of the PFA it produces, and
all the FBA it produces, to companies involved in the production of
concrete blocks and tiles and cement. However due to the limited
market, and the considerable rate of production (over 0.8'million
tonnes in 1988) the company has had to use other means of disposalnotably -
a) disposal on land at a designated site in Hong Kong;
b) export to Macau and China for use in landfill} and
c) disposal to a lagoon.
- 27 -
50. Disposal to a lagoon is a relatively recent innovation in
Hong Kong. Lagoons have been constructed on the foreshore at Tsang
Tsui in the New Territories. PFA is mixed with seawater and pumped
into them as a slurry. It is allowed to settle and the decantrate is
then pumped back to the power station at Castle Peak for disposal
with the power station cooling water via a submarine outfall.
51 • The principal environmental problem associated with the
disposal of PFA on land is dust (generated both at the site and by
vehicles travelling to and from the site). Lagooning coupled with
delivery of PFA in slurry form solves the air pollution problem and
has the additional advantage that the PFA can be dug out of the
lagoons at a later date for re-use as and when requirements arise
and/or markets are identified.
Plate 3. Lagoon used for the storage of PFA slurry at Tsang Tsui,West New Territories
- 29 -
CHAPTER 4 PROPOSALS FOR IMPROVEMENT OF EXISTING ARRANGEMENTS
BACKGROUND
52. The main objective of the plan is to ensure adequate
arrangements for the collection and disposal of various classes of
waste in an environmentally satisfactory manner.
This chapter addresses environmental improvement measures which may
be adopted to overcome the problems and shortcomings identified with
existing practices. (Details of the environmental problems are
described in Appendix C)
WASTE COLLECTION
Household and commercial wastes
(a) Public sector
53. No major changes to the nature of the services provided by
the collection authorities are required. The Government supports the
Municipal Councils1 aim of providing efficient and environmentally
acceptable services for the collection of household and commercial
wastes, and will advise and assist the Councils in their efforts to
improve these services.
- 30 -
Plate 4. Unloading of refuse from plastic wheeled bins (equippedwith self-closing lids) into a refuse collection vehicle
Plate 5. Automatic washing station at a refuse collectionvehicle depot
- 31 -
(b) Private sector
54. The considerable environmental nuisances that are often
generated by private-sector arrangements for municipal waste
collection stem from the fact that the private sector is completely
uncontrolled. There is no authority or central employer with the
power to ensure that private collectors meet certain environmental
standards.
55. One possible means of ensuring that appropriate standards
are met would be to establish a system whereby any person wishing to
operate a collection service for household and commercial waste would
require a licence to do so. The licence could specify the types of
waste which it was permissible for the licensee to collect and could
also include conditions relating to such matters as the types of
vehicles to be used, the washing of vehicles, and the prevention of
littering. The objective of such a licensing scheme would be to
ensure the existence of a number of contractors capable of collecting
and transporting waste in an environmentally acceptable manner*
Waste producers would be free to engage any licensed collector to
collect and remove their waste. The emphasis of the scheme would be
on free competition within a controlled framework.
56. Provision exists within the Waste Disposal Ordinance for
the collection authorities to license the collection of certain types
of wastes. However the wording of the legislation is such that it
may not be suitable as a basis for the establishment of a licensing
system as described in the preceding paragraph. Even if it were,
there could be considerable administrative difficulties in setting up
- 32 -
such a system, not least the problems of inspection and enforcement.
Because of these potential difficulties it is not possible to make a
recommendation concerning licensing at this stage. It is therefore
proposed that the three collection authorities should jointly examine
the feasibility of establishing a licensing system for private
collectors of household and commercial waste.
Industrial and construction wastes
57. Under the provisions of the Waste Disposal Ordinance the
collection authorities are empowered to collect, inter alia, "trade
waste11, which means "waste from any trade, manufacture or business or
any waste building or civil engineering materials, but does not
include animal waste". They are also empowered to license the
collection of these wastes by private contractors.
In practice collection of these types of waste by the collection
authorities is limited to the collection of commercial waste
delivered to RCPs* None of the collection authorities collects
either building and civil engineering waste or waste from
manufacturing processes*
58* It is not considered that the collection and transportation
of either construction waste or general industrial waste need to be
controlled through a licensing system as the potential adverse
environmental impact of these activities is limited and the resources
that would have to be devoted to a licensing system cannot be
justified at the present time.
- 33- -
Clinical waste
59* Arrangements for the collection and disposal of clinical
wastes were studied in 1982 by consultants to the government. A
number of recommendations were made, aimed mainly at ensuring that
firm guidance on the segregation and handling of such wastes was
provided by the medical authorities and that standardised procedures
were followed consistently throughout all medical establishments,
especially those operated by the government. Despite this the
situation remains less than satisfactory. In particular there is a
need for consistency as to which wastes should be incinerated, which
should be removed under special arrangements, and which may be
discarded along with ordinary refuse. There is also a need to
establish procedures to ensure that waste from private doctors1
clinics is properly dealt with. It is therefore proposed that :-
a) the Hospital Services Department and the Department of
Health should re-examine, in conjunction with the
collection authorities, existing procedures for the
segregation, handling and subsequent collection of waste
from hospitals and clinics with a view to developing a code
of practice or directives to ensure consistency of
approach; and
b) a further study should be carried out of the nature and
extent of arisings of clinical wastes from private doctors1
clinics with a view to identifying a satisfactory means of
collecting and disposing of those wastes.
Other wastes
60. The remaining wastes requiring consideration are
"difficult11 (i.e. mainly organic and obnoxious) wastes and wastes
posing special problems such as chemical wastes, and PFA. It is
considered that in order to ensure that these wastes are collected
and transported safely and with minimal environmental impact a
licensing system needs to be established* It is proposed that this
should be done as a matter of priority.
- 34 -
61. For licensing purposes the wastes would be divided into two
categories namely "toxic and hazardous11 and "difficult and special".
Toxic and hazardous wastes would comprise mainly chemical wastes
requiring special handling. Special and difficult wastes would
comprise such materials as sludges, excremental waste, livestock
waste, animal carcasses, and PFA . Contractors wishing to carry any
waste falling into any of these categories would require a licence
from the relevant waste collection authority. For chemical wastes
the conditions would include a requirement that complete and detailed
records be kept of each load of waste collected and delivered for
disposal. It would also be necessary for the waste producer and the
operator of the disposal facility to keep copies of such records.
This "trip ticket system" would enable the waste collection authority
(DEP for chemical wastes) to monitor the fate of all chemical wastes
collected and disposed of in the territory. For wastes falling in
the "special and difficult" category licence conditions would not
need to be so rigorous as those for toxic and hazardous wastes. In
particular waste producers and collectors would probably need only to
keep a log of wastes collected and delivered for disposal.
WASTE DISPOSAL
Landfill
62. Odour at landfills arises both from vehicles delivering
refuse to the site and from the site itself. Odour from vehicles
delivering refuse to the site could be controlled in a number of
ways i-
(i) the waste may be fully containerised;
(ii) the vehicles should be cleaned regularly, both inside andout; and
(iii) leakage of leachate should be avoided.
The use of bulk transfer vehicles or vessels would allow
containerisation of large loads, coupled with the use of smaller RCVs
on collection rounds for delivery to refuse transfer stations. The
provision of vehicle washing facilities at the transfer stations will
help the waste collection and disposal authorities in their efforts
to improve the environmental standards of their operations.
- 35 -
63. The problem of odour generation by refuse deposited at
landfills is not severe, mainly because waste is collected and
delivered to landfills daily. This means the waste has little time
to produce malodorous decomposition products before being covered by
more-recently-collected waste. To ensure that the problem is
minimized, the area of the tipping face should be kept to the minimum
consistent with operational requirements and the refuse should be
well compacted and properly covered with earth.
64. As regards gas control, it is essential that all future
landfills should incorporate properly engineered gas control systems.
Such systems would include wells or sumps where gas would accumulate
together with some means of drawing the gas off. Where landfills can
be established close to industrial areas consideration should be
given at an early stage to the possibility of collecting the gas and
piping it to those areas for use as a fuel.
Plate 6. Landfill gasmonitoring ata purpose builtborehole
~purpose built
- 36 -
65. As rainfall in Hong Kong is high, leachate will always be a
problem wherever there is a possibility of the contamination of
groundwater, water courses or water bodies. As a general rule no
leachate should be allowed to escape from landfill sites into
groundwater or into water bodies which are subject to sensitive uses
(e.g. fish and shellfish culture, or recreation). In practice
leachate at inland sites can be properly controlled by lining sites
with an impermeable membrane and installing an appropriate collection
system prior to operation of the landfill. Leachate can then either
be collected and treated on site prior to disposal via long sea
outfalls or delivered for treatment at sewage works. At marine sites
(i.e. those sites where a part of the sea bed is reclaimed using
refuse) the problems are more complex. The use of synthetic liners
is not feasible unless all the underlying marine mud is excavated.
Work is currently under way in Hong Kong to assess the effectiveness
and feasibility of using natural liners such as bentonite/decomposed
granite mixture or marine mud for such sites.
661 One of the arguments against the use of landfills for waste
disposal is that the land utilised will be effectively sterilised for
many years after the site has been exhausted. Of particular concern
are
(i) the fact that gas is likely to be generated for 50 years or
more after the site is exhausted; and
(ii) the likelihood that due to differential settlement the land
will be unstable for many years after the site is
exhausted.
67. The problem of gas generation can be dealt with by the
prior establishment of a proper gas collection system. However if
venting points are necessary these could present an Impediment .'to any
planned after-use. Settlement problems cannot be completely'overcome
but it may be possible to reduce the adverse effects by ensuring that
waste undergoes as high a degree of compaction as possible at the
time that it is laid down* The in situ density achieved at Hong
- 37 -
Kong's landfills at present is about 0.9 t/m3. If differential
settlement is to be minimised and early use of landfills is to beo
achieved an in situ density of at least 1 t/m should be aimed at.
It would also help if landfills were to be completed and restored in
stages (so that one area of the site is being landscaped while
another is being filled). This would ensure that parts of the site
could be brought into use earlier rather than having to wait for the
whole site to be exhausted. Early cover can also help to reduce
leachate generation. Final cover of up to 2 m of good quality soil,
on top of a drainage layer and an impervious barrier, should be
provided and vegetated to reduce soil erosion and water penetration.
Gas control systems should also be installed to reduce gas migration
problems and the associated fire and asphyxiation hazards. These
measures would probably be sufficient to allow open space development
almost immediately after a site is exhausted and in the long run
might allow the construction of low-rise structures (one to two
storeys) on spread footings.
Plate 7. A low-rise building structure erected at the GinDrinkers' Bay landfill which is being restored in phasesfor passive recreation uses
- 38 -
68. In order to properly restore the completed landfills for
beneficial uses as well as to avoid gas migration problem, in
particular for those landfills located in the urban areas with new
housing and commercial developments in the neighbourhood, EPD is
developing a landfill restoration programme. The programme will
identify those landfills which require more urgent restoration works,
which may include the installation of properly engineered gas and
leachate control systems. The Government has already embarked on a
restoration programme for the Gin Drinkers' Bay and Sai Tso Wan
landfills which will eventually be developed by the Municipal
Councils for passive recreation uses.
Plate 8. Lai Chi Kok incinerator is scheduled to be closed downupon the full commissioning of Kowloon Bay transferstation in April 1990
Incinerators and temporary transfer facility
In view of the environmental problems caused by the
incinerators and the Chai Wan composting plant, these facilities will
be phased out in favour of purpose built refuse transfer stations
which will serve as a facility for the transfer of waste from small
refuse collection vehicles to bulk transfer vehicles and barges. The
waste will then be delivered to landfill sites located in remoter
areas of the territory. This approach is further discussed in
Chapter 5.
- 39 -
Codisposal facility
70. The current practice of codisposal of certain chemical
wastes with municipal waste is controlled through a permit system
administered by the Environmental Protection Department (EPD).
Due to the lack of alternative disposal methods, certain chemical
wastes such as oil-water mixtures, paint waste and organic chemical
residues which are recommended for chemical treatment or high
temperature incineration are now disposed of at landfills by
trenching in limited quantities. To improve the existing situation,
a chemical waste treatment centre will be developed. This is further
discussed in Chapter 5. At the same time, EPD has also commissioned
a consultancy to advise the government on the proper practices and
procedures in carrying out codisposal operations. The consultants
have also recommended certain guidelines on the types and amount of
chemical waste which can be safely codisposed. These recommended
guidelines and procedures will be implemented to reduce the
environmental impact of codisposal practices as well as for
operational safety.
Plate 9.
Delivery of properlypackaged asbestoswaste to Junk Baylandfill forcodisposal withmunicipal waste
- 40 -
Legislative controls
71« Mention has been made of the need to establish appropriate
licensing arrangements to ensure that private waste collectors
operate to acceptable environmental standards. Likewise, an
effective licensing system will also be required to regulate waste
disposal. While disposal of wastes at sea is adequately controlled
under the Dumping at Sea Act 1974 (Overseas Territories) Order 1975,
waste disposal on land is not adequately controlled and amendments to
existing legislative provisions will be required*
72* The existing framework for the control of waste disposal
facilities is provided for in section 16 of the Waste Disposal
Ordinance. Section 16(1) states that
"Subject to subsection (2) a person shall not use* or
permit to be used, any land for the disposal of waste
unless he has a licence from the Director [of Environmental
Protection] to use the land for that purpose»lf
Licences issued under section 16 may, by virtue of section 23, be
subject to such terms and conditions as the issuing authority thinks
fit, and can be cancelled If those terms and conditions are not
observed* While these provisions appear to be sufficient to control
operators of waste disposal facilities they suffer from two notable
deficiencies namely
(a) the uncertainty as to whether land used for the disposal of
waste includes land on which treatment facilities, such as
incinerator plants or transfer stations are operatedj and
(b) the fact that a list of exemptions in subsection (2)
includes land used by the Civil Engineering Services
Department for landfill purposes and unleased land In
respect of which a licence has been issued tinder section 5
of the Crown Land Ordinance (Cap 28)*
- 41 -
The effect of these deficiencies is to exclude all government-
operated facilities from the requirement to be licensed and, hence,
from effective and independent control over the environmental
standards to which they are operated. This is all the more
significant when one considers that government-operated facilities
are currently the only waste treatment and disposal facilities in
Hong Kong. It is therefore intended that section 16 be amended to
extend its application to government-operated or owned waste
treatment and disposal facilities and to clarify that a licence is
also required to operate any waste treatment facility. A suitable
system of inspection and notification will also need to be devised to
ensure that licence conditions are observed.
73. With respect to the disposal of certain classes of waste,
the Waste Disposal Ordinance has provisions for introducing
regulations to exercise tighter controls. The Waste Disposal
(Livestock Waste) Regulations 1988 have already been made for the
purpose of controlling the on-farm disposal of livestock waste in an
environmentally acceptable manner, with the controls being phased in
over a period of 9 years. Regulations are also proposed for
controlling the disposal of chemical waste* A trip ticket system
will be introduced to enable the authority to exercise 'cradle to
grave1 control whereby the movement of waste from the waste source to
the final disposal point is closely monitored.
- 43 -
CHAPTER 5 WASTE DISPOSAL STRATEGY
74. In developing the long-term waste disposal strategy, due
consideration has to be given to the increasing trends of waste
arisings as illustrated inFigure 4 (for details see Appendix B).
Various alternative options have been examined in Appendix D and the
strategy to be followed is outlined in the following paragraphs.
Emphasis has been placed on the disposal strategy for solid municipal
wastes* since they represent a major percentage of the total waste
arisings.
SOLID MUNICIPAL WASTES
75. Resource recovery, incineration and landfilling all have a
role to play in the disposal of household, commercial, industrial and
construction waste. Though composting is not an attractive option as
previously demonstrated by the Chai Wan Composting Plant, other
resource recovery methods could make a more significant contribution
and private sector participation should be encouraged and supported
as far as possible provided that the operation is financially and
economically viable. Incineration should not be ruled out as an
option though it is more expensive in comparison with landfilling and
there will be difficulties in siting new incinerators.
76. For the planning horizon up to 2001, the continued use of
landfill will be the major disposal option. The matters that remain
to be resolved are
(a) the role of incineration and refuse transfer in Hong Kong*s
waste disposal strategy;
(b) whether treatment facilities should be provided to handle
privately-collected waste; and
(c) the development of waste minimization, resource recovery
and recycling as an integral part of the waste disposal
strategy.
* Solid municipal wastes include household, commercial, industrial,construction, and marine collected wastes.
1988(22500 tpd)
2001(30000 tpd)
LEGEND :
Household waste + Marine collected waste
Commercial, Industrial £ Chemical wastes
Construction waste
Coal ash (FBA & PPA)
Difficult & other wastes
Difficult and other wastes Sewage and waterworks sludge; sewage worksscreenings; excremental, livestock andabattoir wastes? animal carcasses andcondemned food and clinical waste.
Figure 4 Quantities of waste by category in 1988 andestimates for 2001
- 45 -
77. To assist in resolving the first two points, a computer-
based planning tool known as the Waste Management Model (WMM) is
being used. The WMM is designed to provide an answer (or answers,
where input data are varied) to the following general problem :
"Given an expected pattern of waste production, the costs
of building and operating various treatment and disposal
facilities, and the costs of transporting wastes to those
facilities, what facilities should be built, where, when
and to what capacity?11
The WMM and its application are fully described in Appendix E.
Final disposal sites
78. From an original list of some 50 possible sites, the
Environmental Protection Department identified a total of 11 sites
with the potential for development into landfills. These are as
listed in Table 4. The locations of the 11 sites are illustrated in
Figure 5. None of the sites are in or near urban areas.
Table 4 Capacities and calculated life times of 11 potentialstrategic landfills and two potential incinerators*
Site
LandfillsJunk Bay SouthThree Fathoms CoveBay south of Flat ReefSite south ofWong Mau Hang Shan
Wong Mau Hang ShanNorth of Crown RidgeTin Shui WaiNim Wan SouthNira Wan NorthSiu Ho WanKau Sai Chau
IncineratorsPillar PointHa Mei Wan
Capacitym cubicmetres/t.p.d.
28292928
373810575734 .89
24002400
2Lifetime (years)
15161615
2021632321949
2525
capacity expressed in million cubic metres for landfills, andtonnes per day for incineratorslifetime calculated for landfills on the basis of a daily intakeof 5000 tpd
- 46 -
GUANGDONG SHENG WONOMAI
N
Figure 5 Potential sites for future solid waste disposalfacilities in Hong Kong under consideration in1983 study
79. Based on a costing study carried out in 1983, the estimated
cost per tonne-of waste disposed of at landfill ranged from $38 to
$75. The estimates take into account the construction, operation and
restoration costs but exclude costs of transportation. Three of the
sites in particular represent especially costly options as far as
construction, operation and restoration are concerned. The sites in
question are Three Fathoms Cove (Tolo Harbour), Bay South of Flat
Reef (Tolo Channel) and Kau Sai Chau (Sai Rung). All are marine
sites at environmentally sensitive locations and because of this
construction costs are especially high. Initial runs on the WMM
indicated that for these sites transportation costs would also be
very high and this, in conjunction with the high construction costs,
precluded them from further consideration.
- 47 -
80. Of the remaining eight sites three (Nim Wan North, Nim Wan
South and Tin Shui Wai) are located in the western New Territories,
three (Wong Mau Hang Shan, a site south of Wong Mau Hang Shan and the
site north of Crown Ridge) in the northern New Territories, and one
(Junk Bay South or Shek Miu Wan) in the south eastern New
Territories. The existing landfills are distributed in each of these
regions thus providing regional disposal facilities. There should be
at least three new landfills distributed on a regional basis for the
following reasons :-
(a) by 2001 daily municipal .waste arjLsinjg j ^ to
^amount tosome16^730tonnes. This quantity could not be
handled by one or two landfills simply because of the
strain that would be placed on the surrounding road network
and on the sites themselves;
(b) considerable increases in arisings are projected for the
western and north-eastern New Territories in particular and
it would therefore be sensible to provide a disposal
facility in each of these areas to help reduce transport
costs; and
(c) there will continue to be a need for a final disposal
facility in reasonable proximity to Hong Kong Island in
order to contain transport costs for wastes from the urban
area.
The sites have therefore been examined with a view to reducing the
number to one in the western New Territories and one in the north.
The adoption of Junk Bay South (or Shek Miu Wan) as a site for a
landfill is confirmed in the absence of any alternative in the south
eastern New Territories.
81. With regard to the western New Territories it has been
decided to exclude the site at Tin Shui Wai on the grounds that to
establish a landfill there could severely hamper planning for future
development in the Tin Shui Wai New Town area. In order to
facilitate the choice between Nim Wan South and Nim Wan North the
- 48 -
WMM has been used to assess the equivalent costs per tonne of refuse
disposed of. For this purpose the costs assessed were the costs of
constructing and operating the sites, and the costs of transporting
publicly-collected waste from the western New Territories catchment
area (Tsuen Wan, Tuen Mun, Yuen Long) for disposal at each of the
sites. The results indicate that the costs of establishing and
operating a landfill at Nim Wan South would be about 12%% less than
operating one at Nim Wan North. In addition the construction of a
site at Nim Wan North would entail the resumption and clearance of a
considerable number of properties and the displacement of many more
people than would a site at Nim Wan South. The preferred site for
the western New Territories is therefore Nim Wan South.
82. A comparison of the costs of operating the three potential
northern New Territories sites for the disposal of wastes arising in
the north east New Territories catchment area (i.e. wastes from Sha
Tin, Tai Po and Sheung Shui) has also been carried out. The results
indicate that the costs of waste disposal at Wong Mau Hang Shan and
south of Wong Mau Hang Shan would be virtually identical while the
cost of waste disposal at Crown Ridge would be marginally higher than
the costs at the other two sites. Further investigations revealed
that the Wong Mau Hang Shan site would have considerable advantages
over the remaining two sites in that it would involve less land
resumption and would be less disruptive for the local population.
Wong Mau Hang Shan has therefore been selected as the most feasible
landfill site in this area.
83. The list of potential landfill sites therefore reduces to :
Nim Wan South (West New Territories landfill - WENT),
Wong Mau Hang Shan (North-east New Territorieslandfill - NENT),
Shek Miu Wan (South-east New Territorieslandfill - SENT); and
Sin Ho Wan (Lantau).
The first three must be considered as firm sites because
they are regionally based. A landfill at Siu Ho Wan has not been
further considered because of its reduced strategic Importance* The
earliest possible date of commissioning of the WENT landfill is 1991
and that for NENTf 1993. SENT will not be commissioned until 1994*
- 49 ~
Strategy evaluation to arrive at a least-cost plan for waste disposal
84* Having identified the potential final disposal sites it is
necessary to decide upon the optimum provision of waste treatment
facilities that will enable costs to be kept to a minimum. The basic
treatment methods under consideration involve transfer stations and
incinerator plants* To be viable options both types of facility
would need to be located close to the centroids of waste arisings so
that their relatively high capital and operating costs are offset by
lower transport costs. Because of the need to comply with airport
height restrictions, to avoid sites in close proximity to residential
buildings, and to avoid areas where there is a high potential for
entrapment of pollutants, only two possible sites have been
identified where an incinerator could be constructed. These are at
Ha Mei Wan, Lamma Island and Pillar Point, Tuen Mun. Based on the
costing study in 1983, the estimated cost per tonne of refuse
processed which would be incurred by building a 2400 t.p.d.
incinerator with energy recovery at either site would be two to three
times as high as landfilling cost; this has included the
transportation and final disposal cost of incinerator ash produced.
Preliminary runs with the WMM indicated that the costs for the
transportation of waste which would be associated with the use of
either of these facilities would be large and consequently the
possibility of incineration as a treatment method has been excluded
from further consideration within the planning horizon of 2001 used
in this document.
85. The WMM has been used to investigate options for the future
provision of transfer stations in combination with the final disposal
facilities. {Waste transfer is a waste treatment technique that
effects virtually no reduction in waste mass and Is aimed primarily
at reducing the costs of transporting waste to a point of final
disposal. The cost advantage would be greater for those final
disposal sites located at a longer distance from the waste arisings
- 50 -
areas. The concept involves the construction of a number of
strategically - located transfer stations close to the centroids of
waste arisings. Vehicles which have collected waste from the points
of arisings deliver it to a transfer station where it is transferred,
with or without treatment, into a larger vehicle for haulage in bulk
to a final disposal facility. The large vehicle may be a lorry, if
road transport is utilised, or a barge if transport is to be by sea.
A transfer station may include facilities for the compaction of waste
to increase the payload of the bulk transfer vehicles. A further
advantage of using a transfer station to treat waste prior to final
disposal is that it provides the opportunity for waste to be
containerised prior to haulage to a final disposal site. This would
help to considerably reduce the problems of odour and leachate during
transportation. If direct discharge of waste to containers were to
be adopted odour would also be reduced at the transfer station
itself/I
86. Three waste management strategies, namely direct haul,
transfer facilities for public sector only^j and transfer facilities
for both public and private sectors have been examined. The results
show that the environmental benefits that would flow from providing
transfer facilities for both publicly- and privately-collected waste
are achievable at no greater cost to the public sector than would be
incurred by providing transfer facilities to deal with publicly-
collected wastes only. The private sector too would realise savings
compared with a system in which all privately-collected waste was
hauled directly to landfills. It is therefore proposed that the
capacity of transfer facilities should be planned to cater ultimately
for both publicly- and privately-collected waste in the medium to
long term and that this is achieved by approrpriate planning of
transfer station capacity.
- 51 -
Programme
87. To summarise, the proposed long-term plan for disposal of
municipal wastes is one based on strategically located regional
landfills together with a network of transfer stations constructed so
as to provide capacity for dealing with both publicly- and
privately-collected waste. This disposal strategy envisages the
closure of the Lai Chi Kok and Kennedy Town incinerators at the
earliest opportunity. Its major elements, incorporating the
preferred options and the chronology, are as follows :
Year Event
1989 „ Lai jChi_ Kqk_irijcu e£ator station B closed down upon
recornmissioning of station A
1990 Transfer station commissioned in Kowloon Bay; Jordan Vatley/
landfill and Lai Chi Kok incinerator station A then closed
down
1991 ChajL Wan . pulverisajii^ that the
development of a new transfer station on the same site may
begin
1991 .. WENT strategic landfill commissioned; Pillar Point Valley
- 92 landfill then closed down
Island East transfer station commissioned in Chai Wan;
Kennedy Town incinerator then, closed down
1993 , .................... NENT strategic landfill commissioned; Shuen Wan landfill
- 94 then closed down /x
Island West transfer station commissioned in Westerndistrict
Transfer station commissioned in Yuen Long/Tuen Mun
Transfer station commissioned in Sha Tin
SENT strategic landfill commissioned; Junk Bay/landfill
then closed down
1995 - Transfer stations commissioned in West Kowloon,
2001 Tai.Po and possibly North Point
Kwai Chung TSSInefafor will be closed down when the
transfer station in West Kowloon is commissioned
This table does not show temporary disposal facilities that will be
required as emergency backups whilst the main elements of the
disposal strategy are being developed.
- 52 -
88, The locations of the strategic landfills mentioned above
are illustrated in Figure 6. The locations of the proposed and
possible future transfer stations, also illustrated in Figure 6, are
as follows:
Transfer station Location
Island East, HKI
Island West, HKI
North Point, HKI*
Kowloon Bay
West Kowloon
Yuen Long/Tuen Mun
Sha Tin
Tai Po*
Site of the Chai Wan pulverisation
plant
Western reclamation or Mount Davis
Causeway Bay reclamation
Sheung Yee Rd/Cheung Yip St.
West Kowloon reclamation
(site not yet identified)
along Yuen Long - Tuen Mun corridor
Area 65B
Not yet identified
* possible future transfer stations
NGUANGDONG SHENG
Figure 6 . ..Proposed location. of. future refuse transfer'•' . " • • ' ' stations ;axid'Strategic landfills .
- 53 -
The Kowloon Bay transfer station has a capacity of 1800 tpd, while
the capacities of other transfer stations in the urban areas would be
around 1000 - 1800 tpd. The transfer stations in the NT regions
would have smaller capacities in the range of 500 - 800 tpd.
Plate 10. Artist's impression of the layout of Kowloon Baytransfer station
Plate 11. Schematic diagram of refuse transfer operation
CONSTRUCTION WASTES
89, Though the three strategic landfills have adequate capacity
for the projected waste arisings in the next 20 to 30 years, to cope
with the increasing volume of construction wastes, the following
measures should be adopted as far as practicable :-
(a) Waste Reduction
i) The buildipg industry to consider the reduction of
timber waste at source; reuse of suitable materials on
site; and segregating at source the undesirable waste
materials (such as paper, timber, plastic) from
building debris to increase the proportion of suitable
materials for land reclamation purposes*
ii) The provision of disincentives to dispose of inert
construction waste at landfills through charging.
(b) Maximized utilization at landfills
i) The provision of incentives in the Works Contract in
the use of suitable construction waste to substitute
imported borrow soft material as cover materials*
ii) The provision of a separate daily tipping face for the
disposal of the remaining fnon~usablef inert
construction waste where cover material would not be
required,
iii) Sorting of construction waste at landfills to
facilitate further reprocessing of useful materials.
(c) Adequate provision of public dumping sites
i) Provision of long-term public dumping sites .on a
• ' . , . ^ • '• ' • ; regional /sub-regional basis to, meet the continual
• •• •• ' requirement for /disposal of inert construction waste'
. • '"materials* The provision' of these;.facilities should'
, ' • • . . ' ; ; t i e in';with future long-term 'marine .reclamation '
developments, to be supplemented by barge reception
, . • • /facilities ,at strategic locations , for .onward .transfer'
to reclamation sites* ' '' • ' :
- 55 -
ii) Allocation of suitable areas at new reclamations for
the disposal of certain categories of the presently
marginal or 'out of specification1 materials, taking
into account environmental and site formation
considerations. Examples may include areas above
sea-level and/or areas behind seawall at marine
reclamations.
Plate 12. Construction waste contains much useful materialssuch as timber and wood waste which should besegregated at source for reuse and recycling
DREDGED AND EXCAVATED WASTES
90. The preferred option is marine dumping with control
exercised through the licensing system established under the Dumping
At Sea Act 1974 (Overseas Territories Order) 1975. There are three
existing spoil grounds for marine dumping. The site at Cheung Chau
has already been realigned to increase its capacity. In light of the
limited capacity of the existing sites and the increase in
reclamation activity, it is essential to examine alternative sites to
meet future disposal needs. Factors which would be taken into
account in the siting of new spoil grounds include the effects on
marine ecosystem, fisheries resources, human health and welfare,
shorelines and beaches, shipping lanes and existing uses of the
seafloor, as well as the available capacity and the distance of the
spoil grounds from the major sources of waste.
- 56 -
DIFFICULT WASTE
91. Landftiling has been and will continue to be adopted for
the disposal of a small fraction of difficult waste. However,
landfill is not the preferred option for certain difficult waste, for
example diseased animal carcasses and raw livestock manure.
Moreover, to conserve the landfill capacity for the disposal of the
rest of the solid municipal waste which is comparatively much greater
in volume, alternative disposal options will be the main elements of
the disposal strategy for difficult waste as outlined below.
Sewage sludge andwaterworks sludge
92. Landfill, incineration and sea dumping are identified as
possible options for the disposal of sewage sludge* A comparison of
the costs of these three options has indicated that for sludge
arising at treatment works which are in close proximity to moderately
deep water sea frontage, dumping at sea is about 60% cheaper than
dewatering followed by disposal at landfill, which is in turn about
half the cost of dewatering followed by incineration. On the basis
of this cost comparison and a subsequent detailed feasibility study
by consultants it has been concluded that action should be taken
immediately to arrange for the disposal at sea of all stabilised
sewage sludges generated at the Sha Tin Sewage Treatment Works, with
the option of extending this disposal plan at a later date to sludges
arising in Tai Po and North Districts. The position of the proposed
sludge disposal site is illustrated in Figure 7* Appropriate
berthing and loading facilities will be commissioned in Tolo Harbour
in early 1991.
930 As a safeguard against the possibility that the dumping
programme might, have adverse effects the government has established a
comprehensive environmental monitoring programme. *A major baseline
study of the physical, chemical and biological characteristics of the
area is currently being carried out. There will be a limited survey
in 1991 and further comprehensive surveys will be carried out in
subsequent years. The environmental effects will thus be monitored
regularly and a major review will be conducted after five years1
operation with a view to deciding whether dumping should be allowed
- 57 -
to continue and, if so, whether the quantities dumped may be
increased to include sludges from Tai Po and North districts,
GUANGDONG SHENG
( Sludge <f?tDisposalSite
P Environmental-/v Monitoring
Figure 7 Location of proposed sludge dumping ground
94, For sewage sludges arising in areas not in close proximity
to a suitable waterfront, disposal will have to be to landfill. The
sludge will first have to be dewatered and disposal carried out in
such a way that it will not produce operational difficulties at the
landfill or localised leachate, gas, and settlement problems. Prior
experimentation will be necessary to determine the best way of mixing
sludge with other refuse in order to avoid these problems.
- 58
Codisposal of dewatered sewage sludge at Shuen Wanlandfill
95. Since marine dumping is not seen as necessarily the best
long-term option for the disposal of sludges, and there is a need to
conserve landfill capacity, EPD is giving consideration to
alternative, recently developed processes for dealing with sludges
such as fluidised bed incineration, high efficiency filtration and
the production of oil from sludge.
96. Options for disposal of water works sludge are limited to
dumping at sea or discharge to coastal waters via a long sea outfall.
Since a decision has been made to dump Sha Tin's sewage sludge at sea
it is intended that Sha Tin's water treatment works sludge should be
disposed of in a similar manner. As with sewage sludges, the
possibility of disposing of alum sludge from Tai Po and North
districts in the same way will be reviewed at a later date.
Improved methods of dealing with water works sludges in other areas
have not yet been worked out, and this problem will need to be
addressed separately.
- 59 -
Livestock waste
97. Composting of raw manure for subsequent recycling as
fertilizer has been identified as the primary means of disposal. In
order to tie in with the phased implementation of the regulatory
control on livestock waste disposal, the existing capacity for
composting livestock waste has to be expanded according to the
following programme :
1990 Ngau Tarn Mei composting plant to be expanded to acapacity of 25 t.p.d.;
1991 50 t.p.d. consolidation site to be commissioned atSite A in the north east New Territories;
1991 50 t.p.d. consolidation site to be commissioned inthe south west New Territories;
1993 250 t.p.d. consolidation site to be commissioned inthe north west New Territories;
1993 100 t.p.d. consolidation site to be commissioned atSite B in the north east New Territories;
1995 20 t.p.d. consolidation site to be commissioned inthe south east New Territories;
1996 10 t.p.d. consolidation site to be commissioned inthe Islands District.
Plate 14. Collection of dry muck-out livestock waste at thelivestock waste collection point
- 60 -
Animal carcasses
98. Cremation is the preferred method for the disposal of
animal carcasses. The existing method of cremating dead animals at
the abattoir incinerators is not desirable because the abattoir
incinerators are designed to cater only for the destruction of any
diseased animals which are orginally intended for slaughter.
Consequently it would not be appropriate or possible to use the
abattoir incinerators for this purpose on a long term basis. It is
therefore proposed that a special cremator be constructed for the
disposal of animal carcasses. The small quantities, high temperature
and long residence times would ensure no significant air pollution.
The ash would be disposal of at landfill.
CLINICAL WASTE
99. Clinical waste should ideally be incinerated in
purpose-built incinerators in order to safeguard public health.
Incineration in municipal incinerators is not appropriate because of
the danger of incomplete combustion. All future planned hospitals,
whether in the public or private sector, should therefore incorporate
incinerators with adequate 'capacity to deal with the wastes produced.
The incinerators should be capable of achieving complete combustion
of material* It is recommended that for public and private hospitals
and. clinics whose incineration capacity is inadequate or cannot meet
the air emission standards,-the ..clinical waste should be collected
and disposed of at.a centralised facility, which could incorporate a
cremator'.for dealing with animal carcasses as mentioned earlier.
CHEMICAL WASTE ' , ' '. ' • ' ' . ' •
100. ' ' ' ''.'Most .chemical • wastes' require .treatment'before'disposal* , A
chemical waste treatment 'Centre will be 'developed.on Tsing Yi for
this purpose..'. Its location is shown' in. .Fig 8. The centre'will
incorporate physico-chemical' treatment processes, 'for aqueous, waste,: :
an oily waste recovery process, and a high temperature Incinerator.
- 61 -
101. The incinerator will deal with relatively small
quantities of waste (about 40 t.p.d.). It will be fitted with
up-to7date particle removing and gas cleaning equipment and will
incorporate a stack with a minimum height of 75 m. The intake will
be carefully controlled and this, together with the limited
quantities of waste to be dealt with and the presence of modern
pollution control technology will ensure that the plant gives rise to
no adverse environmental impact.
Reserved Site forChemical WasteTreatment Centre
Junk BayCodisposal Landfill
South East NTLandfill (futurecodisposal landfill)
Figure 8 Location of the Chemical Waste TreatmentCentre and the codisposal landfills
102, The residue generated from the treatment centre will have
to be disposed of at landfill. It is intended to codispose the
residue at Junk Bay Landfill (and the SENT landfill in the future).
Waste which does not require prior treatment , for example asbestos
waste and tannery offcuts* will be sent directly to the landfill for
codisposal*
- 62 -
RADIOACTIVE WASTE
103. Existing methods of disposal of radioactive wastes are
generally adequate. There is a possibility that some wastes
currently disposed of by storage underground could be dealt with by
codisposal at a landfill. This may allow for the establishment of a
smaller, purpose-built, long term storage chamber. A separate study
has been initiated to investigate these possibilities.
PFA & FBA
104. The preferred option for disposal of PFA and FBA is by sale
on a commercial basis, followed by lagooning if sale outlets cannot
be found. Use of PFA and FBA in land restoration and reclamation is
to be investigated as a possible long-term solution to the disposal
problem.
Plate 15. PFA land reclamation trial at Siu Lang Shiu
- 63 -
SUMMARY OF THE STRATEGY
105. In summary, with regard to the future waste disposal
strategy, the following conclusions have been reached :
i) for final disposal of solid municipal wastes, landfillcoupled with a network of transfer stations is theappropriate disposal option;
ii) construction waste should be reduced at source, and theunusable remainder sent to the public dumps forreclamation purposes or to the landfills for use as covermaterial as far as practicable;
iii) dredged and excavated soils should continue to be dumpedat sea with new marine dumping sites identified to meetthe future needs;
iv) sewage sludge should be disposed of partly at sea andpartly at landfill;
v) water works sludges should be disposed of at sea either bymarine dumping or long sea outfall;
vi) livestock waste should be composted for use as afertiliser as far as practicable;
vii) animal carcasses and clinical waste not incinerated athospitals should be destroyed in a purpose-builtincinerator;
viii) chemical wastes should be treated at a purpose-builtchemical waste treatment centre and residues should besubject to codisposal at landfills;
ix) radioactive waste should be stored at a purpose-built longterm storage chamber or possibly codisposed at landfills;and
x) PFA and FBA should be sold for re-use in buildingproducts, or lagooned for long term storage, while its usefor land restoration and reclamation should beinvestigated as a possible long-term disposal option.
106. The costs which will be incurred in constructing and
operating the proposed major waste management facilities as required
for (i), (vii) and (viii) have been estimated and are set out in
Appendix F.
- 65 -
CHAPTER 6 THE WAY FORWARD
PLANNING BEYOND 2001
107. Earlier chapters have examined the existing and future
arrangements for the collection and disposal of various classes of
waste. The growth in population and commercial and industrial
activities inevitably brings about an increasing volume of waste. Major
development schemes such as port development, urban renewal programmes
and other large scale reclamations exert additional pressures on the
scarce resources available for the disposal of municipal and other
wastes. New pollution control legislation and programmes will also
generate more sludges requiring disposal.
108. The emphasis so far in the Government's approach to waste
management has been to provide secure long term strategies for the
disposal of the growing quantity of wastes produced by our community,
together with provisions to prevent environmental problems associated
with waste collection and disposal. Strategies to limit the amount of
waste generated must now be developed, and the recovery and recycling of
wastes encouraged.
THE OPPORTUNITY TO MINIMIZE WASTE GENERATION
109. The more affluent a society becomes, the larger the per
capita waste generation* Excessive waste generation, apart from the
fact that valuable resources are wasted, also exacerbates the waste
disposal problem. To reverse the increasing trend of waste generation,
there is a need to educate the public and to encourage a change in
attitude towards waste generation. The industrial sector should also
make serious efforts in reducing waste generation by better housekeeping
and process control, suitable changes to their existing practices and
adoption of clean technology. The servicing and retail sectors should
also contribute by exerpising stricter control measures, for example,
restriction on the free distribution of plastic bags and tighter
stock-taking of those consumer products with limited shelf-life. The
use of environmentally desirable packagings for consumer products would
also contribute towards waste minimization and resource conservation. A
- 66 -
waste exchange scheme is also worth consideration by industry. The
scheme involves the exchange of waste materials and hence will maximize
the reuse of waste materials by various industries.
THE OPPORTUNITY TO PROMOTE RESOURCE RECOVERY
110. At present, recycling activity is mainly export-oriented as
most materials with recycling value are scavenged by scrap dealers for
export to other countries. There is already a substantial waste
recycling industry in Hong Kong. Over 1 million tonnes of wastes were
exported in 1988, which is equivalent to 24% of the total arisings of
municipal waste. This recycling activity generated nearly 2.2 billion
dollars in export earnings in 1988.
111. An export-oriented recycling activity is very much dependent
on the demand from overseas markets and is vulnerable to market forces
beyond our control. Any sudden collapse of the market for a particular
type of scavenged material would place a burden on the government to
identify alternative disposal outlets. Therefore, apart from close
monitoring of the extent of recycling activity, further opportunities to
recover wastes and to establish stable markets for recycling should be
explored and promoted.
Plate 16. Baled waste paper intended for export to the neighbouringSouth-east Asian Countries
- 67 -
112. The Environmental Protection Department has recognised that a
lot of the waste materials that are currently disposed of at landfills
may have comparatively low recovery value in commercial terms or may
require more elaborate reprocessing and marketing efforts for the
recycled products. It is the Government's intention, therefore, to
identify practicable measures to promote, facilitate and support waste
recovery and recycling schemes that have an overall beneficial effect on
waste management. The principles of Government support and assistance
being considered cover the following:-
giving preference and assistance in the establishment of
commercial recovery and recycling schemes that are able to
reduce the demand for waste disposal;
. giving favourable consideration in the procurement and
application of recycled products within Government;
increasing the effectiveness of the dissemination o*f
information on waste recovery and recycling to the industry;
and
increasing the relative recovery value of waste materials
through possible imposition of waste disposal fees on waste
producers.
113. It remains the Government's view that direct participation in
waste recovery and recycling activities is not appropriate for the
Government* With its greater degree of flexibility and marketing
ability, the private sector is better placed to embark on; resource
recovery ventures based on innovative technology. The support measures
being considered by the Government are mainly intended to complement the
industry which has the necessary knowhow and flexibility required for
viable recycling developments.
114* There is also scope for promoting a larger extent of waste
separation at source so as to facilitate waste recycling. However any
such arrangement would require more public participation and
cooperation, and education will be an essential component of any related
promotion campaign.
- 68 -
THE ROLE OF THE PRIVATE SECTOR
115. Although all Hong Kong's waste disposal and treatment
facilities are currently operated by the government this does not mean
that the private sector is necessarily to be excluded from operating
such facilities* The design, construction and operation of waste
disposal, and treatment facilities by the private sector, based on some
form of contractual arrangement with the government, would have a number
of potential advantages such as the transfer of professional experience,
provision of financial incentives for good management and greater
operational flexibility. It is therefore the government^ intention
that in future the possibility of private sector involvement in the
design, construction and operation of waste treatment and disposal
facilities be investigated whenever it is appropriate*
CHARGIHG POLICY
116. Currently, the government provides all waste treatment and
disposal facilities free of charge* In the case of-household waste,
householders are responsible only for the delivery of the waste to the
collection points for removal by the collection authorities and in most
circumstances the waste is delivered to the collection points by hired
contractors* In the case of commercial and industrial waste suitable
for disposal at landfills, waste producers are responsible only for the
cost of transporting their waste to the landfills* In the case of
chemical waste which is mainly discharged as liquid effluents, both
collection facilities (sewerage systems) and disposal facilities (sewage
treatment works) are provided free of charge* In the case of livestock
waste, the collection service is initially provided free of charge but
the subsidy will gradually be phased out so that the cost is eventually
borne by the farmers. In the case of dredged and excavated wastes, the
waste producers are responsible only for the cost of transporting the
wastes to the marine dumping sites, and the licence fees only cover the
administrative costs of the scheme.
- 69 -
117. As earlier discussed, transfer stations have a key role to
play in our future waste disposal strategy. Apart from the potential
cost savings and environmental benefits, the network of transfer
stations will also facilitate the even distribution of wastes to the
three strategic landfills (ie. North-east NT Landfill (NENT), West NT
Landfill (WENT) and South-east NT Landfill (SENT)). However, if full
costs are charged at the transfer stations for privately-collected
waste, private waste disposal contractors would have less incentive to
utilize the service of the transfer stations, preferring to send wastes
directly to the strategic landfills, which are provided free of charge.
This may lead to an uneven distribution of the waste at the three
landfills resulting in an early exhaustion of the capacity of the most
popular landfill, apart from the operational difficulty of coping with a
large number of small collection vehicles at a popular landfill. To
reduce the cost disincentive and to encourage the full utilization of "
transfer stations, there is a need to review the existing charging
arrangement which has a number of inconsistencies as outlined earlier.
LEGISLATIVE CONTROL
118. The Waste Disposal Ordinance has provisions for licensing of
waste collection and disposal services. However, the ordinance has
certain deficiencies which will have to be rectified by legislative
amendments. At the same time, certain provisions cannot be implemented
until the necessary regulations have been made. The major legislative
amendments will be «-
improving the legal definition of "waste";
reclassifying and defining various classes of waste to
facilitate the division of responsibilities between various
government departments and the municipal councils and for the
purpose of licensing control;
- 70 -
defining 'disposal' to ensure all parts of the waste
management chain beyond 'collections ie. reception,
treatment and interim storage as well as final disposal, are
controlled;
improving the existing licensing provisions with respect to
the collection and disposal of waste;
extending the licensing controls to cover all government
disposal operations;
imposing greater responsibility on waste producers to
assume the duty of care for certain classes of waste;
imposing stricter control on the import and export of waste.
- Al -
APPENDIX A
TYPES AND QUANTITIES OF CUREENT WASTE ARISINGS
WASTE TYPES
1.1 The types of waste with which this document is concerned,the agencies effecting their collection and transportation, and theexisting method of disposal adopted for each are summarised inTable A.I* In more detail the wastes are as follows.
Household waste
1.2 Household waste is waste generated by individual householdsin the course of their normal daily activities. It includes bulkyitems such as furniture and domestic appliances as well as the typeof material that normally finds its way into the average householdrubbish bin (e.g. food waste, paper, plastics). It is collected andtransported to a disposal point by the Urban Services Department(USD), the Regional Services Department (RSD) and by numerous privatecontractors. It is treated or disposed of at one of the territory'sincinerators, at the pulverisation plant at Chai Wan, or at one ofthe territory's landfills.
Street waste . . ' • , • • .• , • ' ' . .
1.3 Street waste is essentially dirt and litter collected as aresult of street cleansing activity by USD and RSD. It includeslitter from litter bins and from beaches and country parks. It isdisposed of in the same way as household waste.
Marine collected waste
1.4 Marine collected waste includes both marine floating wasteand waste collected from ocean going vessels moored in VictoriaHarbour and dwelling boats in typhoon shelters. Marine floatingwaste is essentially the marine equivalent of street waste. Marinecollected waste is collected in part by government-owned vesselsunder the control of the Marine Department and in part by privatecontractors. Opce collected the waste is delivered tq a marine wastereception point from where it is transported by contractor to alandfill for final disposal. Marine waste reception pointy arelocated in Kwun Toi*g, Kwai Tsing, Western and Causeway Bay.
- A2 -
Table A.I Estimated arislngs of waste types In 1988 (tonnes/day unless otherwise indicated)
1
2
3
4
5
6
7
8
9
10
11
12
Waste type
Household
Marine collected
Commercial
Industrial
Construction
Dredged & excavatedmaterials
"Difficult"
Sewage sludge
Water works sludge
Sewage works screenings
Excremental waste
Livestock waste
Animal carcasses
Abattoir waste
Condemned food
Chemical
Clinical
Pulverised fuel ash
Furnace bottom ash
Secondary
Incinerator ash
pulverised waste
Ar Is ings
4600a
19b
400
1400
6500
48800°
135d
4000
40
54e
2000f
6.58
35h
108
280
61
2600
380
480
380
Collecting Agency
USD/RSD/private
MD/contract
private
private
private
contract /private
EMSD/private
N.A.
contract
USD/RSD/contract /private
contract
USD/RSD/private
USD/private
private
private
USD/RSD/private
private
private
EMSD
CESD's contract
Existing Disposal Method
pulverisation/ incineration/ landfill
landfill
landfill
landfill
landfill
marine dump ing /pub lie dump
landfill/screening plants
discharge to water course/submarine outfall
landfill
landfill/sewage works/screening plants
composting/recycling/discharge to watercourse
cremation/ landfill/reprocessing
landfill/reprocessing
landfill/reprocessing
discharge to drains/landfill
landfill/incineration
lagooning/recycllng
recycling
landfill
landfill
Footnotes
ab
cd
includes some commercial and all street waste and junk and bulky waste;inludes 4 tonnes of refuse collected from ocean going vessels moored in Victoria Harbour anddwelling boats in typhoon shelters, the rest is marine floating waste.unit in m,/day, does not include quantity disposed of at public dump or reclamation;unit in m /day, 15% dry solid, does not include the small proportion which is sent to screeningplants by the private contractors.47» dry solids} mainly delivered to sewage works for digestion and therefore subsumed withinthe figure for sewage sludge (which is 15-35% dry solids), does not Include privately collectedsludge.a small fraction of dry mucked-out waste is currently collected by EPD contractor forcomposting, A very small proportion is also landfilled. During 1988, nearly 700 tonnes ofcompost was produced.does not include waste reprocessed by USD1sby-product plant or private contractors, nor wastecremated at the abattoir cremators.does not include waste reprocessed by the private contractjors nor the USD's by-product plantdoes not Include waste destroyed at hospitals Incineratorsj for government institutions this isestimated to be about 5 tonnes per day?
contract. « private contractor engaged by a government departmentprivate = private contractor operating entirely independently of the governmentN.A. = not applicable. •USD "as Urban Services DepartmentRSD = Regional Services DepartmentEPD s* Environmental Protection DepartmentCESD - Civil Engineering Services DepartmentEMSD = Electrical and Mechanical Services DepartmentMD w Marine Department • ' . • . ' . ' • • ' ' , • - . ' . " • • ' • ' , ' ' • • " ! . ' . . ' • . • . - . • . ' . ' • .
- A3 —
Commercial waste
1*5 Commercial waste is waste arising from all forms ofcommercial activity such as markets,, shops, restaurants and offices(but not factories). It is collected mainly by private wastedisposal contractors although a proportion is collected by USD andRSD. The proportion collected by the private sector is disposed ofmainly at landfill and the part collected by USD and RSD is disposedof in the same manner as for household waste.
Industrial waste
1-6 Industrial waste is waste arising from any industrialundertaking within the meaning of the Factories and IndustrialUndertakings Ordinance, Cap 59. It includes solid and semi-solidwaste from all the major industries such as the plastics and textilesindustries but excludes chemical wastes and for the purposes of thisreview wastes from the construction industry. Collection andtransportation of these wastes is carried out either by privatecontractors or by direct labour from the undertakings themselves.All such wastes are disposed of at landfills.
CenstrjjLCtIon waste
1.7 Construction waste is waste arising from building activity."It includes various types of building debris, timber, site clearancematerials and mixed soft materials but, for the purposes of thisreview, excludes material such as building rubble which is suitablefor disposal at public dumps* or reclamations. It also excludesexcavated materials produced during site formation which are disposedof either at public dumps or at sea, depending on the nature of thematerial in question. Collection and transportation of constructionwaste is carried out entirely by the private sector and all disposalis to landfill.
Dredged and excavated wastes
1.8 Dredged waste, normally termed 'spoil1, is waste producedas a result of dredging activity in the harbour or along thewaterfront area for purposes either of keeping navigation lanes clearor of constructing a major new facility (er.g* the new containerterminal at Kwai Chung). Excavated wastes comprise mainly completelydecomposed rock,, residual soils, aluvium and marine sand and mudsexcavated during large scale civil engineering works* The formermaterial is normally suitable for reclamation fill purposes anddisposed of at public dumps, and the remainder is usually suitablefor sea disposal together with spoil. Disposal at sea is controlledby licence under the Dumping at Sea Act 1974 (Overseas Territories)Order 1975.
* Public dumps are areas, Invariably located in reclamations, wherebuilding rubble and excavated materials suitable for use in landformation may be disposed ofv They are designated as such by theDirector of Civil Engineering Services.
— A4 —
Difficult waste
1.9 This category mainly comprises organic wastes which areespecially liable to putrefaction and for which special handling,treatment and disposal arrangements may have to be made. Individualwaste types falling within this category are
a) sludge from sewage treatment works: it is currentlydisposed of at landfills; transportation is carried out bythe private contractors, or direct labour from theElectrical and Mechanical Services Department (EMSD) if thetreatment works is government-operated; some wet sludgesare also sent to the screening plants;
b) water works sludge: this is sludge produced as a result ofthe treatment of water with alum to remove fine suspendedmatter; the resulting sludge is gelatinous", inert, andbasically inorganic; at present the arisings are mainlydischarged from water treatment works directly into watercourses;
c) screenings and grit from sewage screening and treatmentplants: these wastes are removed by a private contractorengaged by EMSD and delivered to landfill for disposal;
d) excremental waste; this consists of nightsoil and sludgefrom septic tanks and aqua privies; it is collected mainlyby USD and RSD. Some septic tanks operated by EMSD arede-sludged by a contractor, and some septic tanks arede-sludged privately. The wastes are delivered to landfillor to a number of sewage treatment works and screeningplants for treatment and/or digestion;
e) livestock waste: this is essentially faeces and urineproduced by livestock; at present it is mainly disposed ofsimply by hosing down into the nearest stream although someis composted and recycled to land or used as fertiliser forfish ponds;
f) animal carcasses: these comprise mainly cats and dogs whichhave died or been killed in the street, imported animalswhich arrive dead or which are killed or die in the depotor lairages and farm animals (chiefly chickens, pigs andcattle) which have died on the farm; cats and dogscollected by USD are cremated at the USD abattoirs;carcasses of cats, dogs, chickens, pigs and cattlecollected by RSD were formerly cremated but are nowdisposed of at landfill on a temporary basis; deadanimals unfit for human consumption are also reprocessed inthe by-product plants by USD, and otherwise cremated;
g) abattoir waste: this consists mainly of blood, dung,stomach contents and hair of animals slaughtered atabattoirs; the wastes from Urban Council-run abattoirs areremoved by USD and the wastes from privately-run abattoirsare removed by private contractors;' a11 such wastes areeither reprocessed at the by-product plant at the KennedyTown Abattoir, sold to private contractors for reprocessingor disposed of at landfills.
h) condemned food: this takes the form mainly of tinned orpackaged food or frozen meat which has passed its expirydate or has for some other reason become unfit for humanconsumption; it is disposed of to landfill or, in the caseof meat, by processing in the by-products plant at KennedyTown abattoir.
Chemical waste
1*10 This category encompasses a considerable variety of wastesof different chemical compositions. The major factors they have incommon are that they are toxic or hazardous. As such they need notbe solid or semi-solid and indeed include many liquid wastes such asacid and alkali wastes from the electroplating and printed circuitboard industries. At present it is suspected that only a very smallproportion of such wastes are properly disposed of, for example,asbestos and oily sludges disposed of at landfills. The vastmajority are almost certainly simply poured down the nearest drain.
Clinicalwaste
1.11 Clinical waste comprises offensive (eg. amputated limbs,excised organs), infectious (eg. soiled dressings), dangerous (eg.Pharmaceuticals and chemicals) or difficult (e.g. syringes) wastearising from medical and dental establishments or similar practice.Some of the wastes are disposed of at in-house incinerationfacilities; others are collected by USD under special arrangementsand disposed of at landfill; still others find their way intoordinary commercial refuse deposited at refuse collection points.They are then collected by USD and RSD on ordinary collection rounds.Some wastes from Queen Mary Hospital are transferred to Kennedy TownIncinerator by the Medical and Health Department.
Radioactive waste
1.12 Radioactive waste is essentially any waste containing orconsisting of a radioactive substance as defined in the RadiationOrdinance, Cap. 303. Its collection, transportation and disposal arecontrolled by the Radiation Board which is established under theRadiation Ordinance.
±-.13 Radioactive wastes of short half life are required to bestored at the site of origin for such a period of time as isnecessary to allow the radioactivity to decrease to a level which issufficiently low for the wastes to be disposed of safely as ordinaryrefuse. Wastes consisting of sealed sources of longer half life areusually returned to the manufacturer or supplier overseas for
- A6 -
disposal. Those which cannot be returned are stored in a secureunderground chamber managed by the Radiation Board. Encasing inconcrete may be required for some sources. Radioactive wastes whichcontain or consist of unsealed sources, or materials contaminated byunsealed sources, are disposed of locally. Very low level waste isdisposed of as ordinary refuse or, if liquid, poured down the nearestdrain. A small proportion is also disposed of at the landfill undercontrolled manner. The remainder is incinerated or encased inconcrete blocks or drums and stored in the secure undergroundchamber.
Pulverised fuel ash (PFA) and furnace bottom ash (FBA)
1.14. PFA and FBA are process-specific wastes arising from thecombustion of coal to generate power. The only producers of thesewastes in Hong Kong are the two utility companies namely China Lightand Power and Hong Kong Electric. The companies themselves makearrangements for the disposal of the wastes* At present disposalmethods include recycling and the deposit of the wastes in lagoons.
Secondary wastes
.1.15 Secondary wastes are wastes produced at waste treatmentfacilities. In Hong Kong the only secondary wastes requiringdisposal are ash from incinerators and pulverised waste from the ChaiWan pulverisation plant (upto mid 1987 the Chai Wan plant alsoproduced some compost for disposal). Incinerator ash is removed byEMSD while pulverised waste is removed by a contractor engaged byCESD. All the wastes are disposed of at landfills.
CURRENT WASTE ARISINGS
1.16 Table A.I also sets out the estimated arisings of waste bytype in 1988. The estimates have been
(a), derived from data collected by the Environmental ProtectionDepartment (EPD) during its twice-yearly survey of wastesdelivered to government-operated facilities;
(b) provided by government departments responsible for thecollection or disposal of specific types of waste (forexample, estimates of the arisings of sewage treatmentworks screenings and grit are provided by the Electricaland Mechanical Services Department); and
(c) provided by private enterprises (data relating to PFAarisings) or consultants (data relating to arisings ofchemical wastes).
- A7 -
1.17 Because the EPD survey is carried out at disposal pointsrather than sources of origin the data generated therefrom are likelyto lack resolution. Thus the figure for annual arisings of householdwaste includes street waste and some commercial waste which arecollected by USD and RSD and delivered to disposal points togetherwith household waste. It is not possible to provide an overallestimate of the quantity of radioactive waste disposed of in 1988because of the variation in the types of radiomiclides and the formof the waste disposed of-.
1*18 A detailed breakdown of the many types of chemical waste,and their estimated annual arisings, is given in Table A.2.
COMPOSITION OF HOUSEHOLD WASTE
1,19 It is noteworthy that household waste constitutes well overone-third the daily arisings of primary waste disposed of atlandfills or incinerators* It is therefore waste which is likely toloom large in any strategic planning* Because of this it isimportant to consider its composition and physical characteristics asthis could have a bearing on the waste disposal method or methodsfinally adopted*
1.20 The composition of household waste as determined fromsamples taken from municipal waste collection vehicles is presentedin Figure A.I The largest single fraction is putrescible matter,with paper and plastics constituting the second and third largestfractions respectively. The presence of the relatively largeputrescible fraction is reflected in the moisture content which, insurveys carried out in 1988, averaged 4070«
1*21 The information contained in Figure A*l is repeated in theform of a pie diagram in Figure A*2 along with profiles of domesticsolid waste from other cities and countries'. Although the data inthis figure must be interpreted with care (because the studies werecarried out at widely differing times) it would appear that HongKong's domestic waste.may;. be characterised £S. being, ; ljthe content of paper*, metals and glass but relatively high in Clasticand putrescibles (but not as high in putrescibles as domestic wastein Singapore, Sydney and Melbourne). The relatively low paper andmetals content is probably a reflection of the degree of recyclingthat takes place in Hong Kong* The relatively high proportion ofplastics and low proportion of glass probably reflect the extensiveuse of plastic bags and containers and the limited use of glassbottles* These characteristics could indicate that conventionalresource recovery methods for the treatment of Hong Kongfs domesticwaste may not be applicable*
- A8 -
Table A.2Estimated Current Axis ings of Chemical Wastes In Hong Kong In 1988.
Waste Type
Acid
Alkali
Copper containing waste solution Acidic spent PCB etchant
Alkaline spent PCBa etchant
Copper waste solution fromother factories
Zinc containing waste solution
Nickel containing waste solution
Other metal salts containing waste solution
Cyanide containing solution
Non-chromium bearing oxidizing agents
Chromium bearing oxidizing agents
Halogenated solvents
Non-halogenated solvents
Phenols and derivatives
Polymerization precursor and production waste
Mineral oil
Fuel oil
Oil/water mixtures
Pharmaceutical products
Mixed organic compounds
Mixed Inorganic compounds
Miscellaneous chemical waste
Interceptor & Treatment Plant sludge
Tank cleaning sludge
Tar, asphalt, bitumen and pitch
Tannery waste
Printing waste
Dyestuff wastes
Plating bath sludges
Paint wastes
Waste catalysts
MARPOL Annex Ib
MARPOL Annex IIC
Quantity(tpa)
20,400
36,400
8,400
5,400
140
13
125
1,200
110
10
55
1,400
1,600
2
40
5,600
50
12,200
1
130
70
30
40
1,000
140
400
90
70
10
650
4
5,000
500
Total (rounded) 101,000
PCB stands for printed circuit board
Prevention of Pollution from Ships (MARPOL Convention).
Chemical waste arising from the application of Annex 11 of MARPOL Convention*
- A9
35
"f 30
CO0
Publicly Collected Waste
ii Area
Urban
NT,
No. ofSamples
214
110
£\[ Urban Area
• NT.
Q±iCOOCLEOOcco0
COoCLEoO
CO
25
20
10UNCLASSIFIED
t -
Privately Collected Waste
35
30
| 25<4-.
20
15
10
Area
Urban
NT.
No. ofSamples
9286
\
UNCLASSIFIED
Figure A,1 Waste composition - waste collected inurban area and New Territories 1988
~ A10 -
20%47%
18%
Melbourne1985
34%
38%
18%
1% 3%
2% 4%
Singapore1987
31% 22%
11%
5%19%
Berlin1978
32%
5%
32%
36%
33%
26%
Sydney
1985
Tokyo1983
33%
28%
17%
4%
Hong Kong1988
10%
New York1984
16% 29%39%
18%
10% 11%
11%17%
14%5%
Switzerland1983
LEGENDS
!%v| Paper \ M V-^'" V
|§ § Putreaclblea
jffijjsll Leather , Rubber & Wood
S$$$S$§I Plastics
Birmingham Pnrjs
1974 1985
fe^?^ Metals
|§§§§§§ Fine Material
| ] Others
fegogo°| Plastics, Building Debris & Others
Figure A,2 Composition of domestic solid waste ina number of cities
- All -
GEOGRAPHICAL DISTRIBIITIOM OF WASTE^ ISIMGS1BELIVERED| TO LAND-BASEDFACILITIES
1*22 For the purposes of the waste arisings surveys Hong Kong isdivided into 19 Waste Arisings Districts (WADs) comprising 53 WasteArising Areas (WAAs). The boundaries of the WADs are shown inFigure A.3. The distribution of municipal waste arisings in 1988, byWAD and by type is given in Figure A*4* The variations between theregions reflect largely the relative differences in construction,development and industrial activity, and in population. Thus inKowloon and the New Territories construction waste forms a muchgreater proportion of the total waste arisings than it does in HongKong primarily because of the ongoing development in the new towns aswell as urban redevelopment.
EXTENT OF WASTE RECYCLING
1.23 As discussed earlier, the relatively low content of paperand metals in Hong Kong's domestic waste is probably a reflection ofactive recycling that takes place. Though it is difficult to findout the extent of recycling, in particular the in-house activity inindustrial establishments, the export statistics of recycled materialcould act as a go'od indicator. The past record clearly shows thatthe recycling activity is export-oriented. The volume and value ofexported materials over the last three years (1986-1988) aretabulated in Table A.3.
A12
Figure A.3 Boundaries of waste arising districts in Hong Kong
- A13
E «3 •§
I I 8LU
(D •.«
§ «
(g |
oCL
C CD O)
o ® § s
O)co
2-fr-id>
o
Jc cJta. •»•»
^ 5!
5 o
H C 6
= 11O * 5
CD
CO
c3
c0
? i £| i g
CD
pco
CO
coCO
LEGENDS
Household Waste Commercial Waste Industrial Waste
Construction Waste Difficult + Marine•••+. Clinical Wastes(Only include those wastes whichare delivered to landfill for disposal)
Figure A.4 Distribution of 1988 waste arisings by district
- A14 -
Table A<s3 Export of Waste Materials (From 1986 to 1988)(Extracted from HK Trade Statistics)
Categories ofWaste Materials
I) Wood & Paper
1) Wood (including sawdust)2) Paper
Sub total
II) Glass
Sub total
III) Plastics
1) Polyethylene2) Polystyrene and copolymers3) Polyvinyl chloride4) Other plastic products in the
form of waste and scrap5) Unhardened rubber
Sub total
IV) Ferrous Metal & Steel
1) Pig or cast iron2) Alloy steel3) Tin plate
Sub total
V) Non-ferrous Metal
1) Copper2) Brass and bronze3) Nickel4) Aluminium5) Lead6) Zinc7) Tin8) Magnesium9) Non ferrous metal ash and residues10) silver waste and sweepings11) Platlnium waste and sweepings12) Other base metals
Sub total
VI) Textile Fibre
1) Silk2) Cotton3) Man made fibres4) Wool/other animal hair (not pulled)5) Wool/other animal hair (pulled)6) Old clothing and other old textile
articles, rags, etc.
Sub total
Total
1986
Quantity(tonnes)
1,334503,033
504,367
822
3,907802
4,940686
150
10,485
5250,7831,170
251,958
7,82415,908
38721,3312,379
3324524131380.4885
49,374
3519,1441,12643729
6,206
26,977
843,983
Value( '000)
1,110259,139
260,249
397
8,5682,55310,4793,248
120
24,968
6216,798
855
217,659
60,647114,1495,143
139,7302,641
70682505
6,898173,53523,8696,944
534,813
78543,9022,2766,898512
10,778
65,151
1,103,237
1987
Quantity(tonnes)
416582,057
582,473
556
6,8205,5188,9581,106
449
22,851
63319,959
-
320,022
10,68422,292
52425,4533,3231096642
1,1982240,4762
64,677
6618,548
985542183
9,295
29,619
1,020,198
Value( '000)
343403,220
403,563
291
11,74511,12119,8953,051
405
46,217
38278,363
-
278,041
95,184189,8337,181
220,0334,251341
1,274440
7,320351,44647,34210,172
934,817
3,09944,0911,8029,1882,82421,037
82,041
1,745,330
1988
Quantity(tonnes)
10,327559,430
609,757
484
26,4139,26119,96910,520
137
66,300
628370,508
7
371,143
20,78229,069
26929,6312,5477375812
1,678360,1-
84,819
2915,737
691413
—4,082
20,952
1,153,455
Value( fOOO)
7,525471,631
479,156
351
60,20224,12750,86724,720
125
160,041
469500,533
15
501,017
246,855296,4008,822
348,0133,7541,8361,165119
7,12655,9605,968
-
976,018
1,89238,2981,5187,939_
7,174
56,821
2,173,404
- Bl -
APPENDIX B
PROJECTED FUTURE WASTE^ ARISINGS
2.1 While it is possible for most waste to be considered on atype-by-type basis, because of the overlap between collectionauthorities and the private sector and because of the lack of properrecords, household, commercial and industrial waste must beconsidered either as publicly-collected waste (i.e. waste collectedby the collection authorities and comprising mainly household waste)or privately-collected waste (i.e. waste collected by the privatesector and comprising mainly industrial and commercial wastes).
PUBLICLY-COLLECTED WASTE
2.2 The quantity of publicly-collected waste arising each yearsince 1974 is shown in Figure B.I, together with a plot of thepublicly-collected waste arisings per head of population. Both areclearly on a rising trend, but the quantity of waste arising per headof population is not expected to continue to increase ad infinitum.In Tokyo, arisings per head have levelled off at 0.9 Kg per day.Since Tokyo is an Asian city it is presumed that it may serve as areasonable model for Hong Kong. However, since the publicly-collected waste contains an element of commercial waste, and in lightof the general trend of increase as experienced in Singapore wherethe per capita generation rate of mixed waste (ie. household wasteand commercial trade waste) approaches 1*0 kg/day, the same figure of1.0 kg/head/day is chosen as the limit of growth.
2.3 The data on arisings per head of population per day havebeen fitted to a straight line by linear regression and the equationobtained used to obtain a projection, also shown in Fig B.I, offuture arisings per head, with the constraint that these should notexceed 1.0 Kg per day. Population projections obtained from theCensus and Statistics Department were combined with projectedarisings per head to obtain projections of total arisings ofpublicly-collected waste per day. These projections indicate that by2001 the daily arisings of publicly-collected waste will beapproximately 6230 tonnes.
PRIVATELY-COLLECTED MIXED WASTE
2.4 Data on past arisings of privately-collected household,commercial and industrial waste are presented in Figure B.2.Arisings per employee have been fitted to a straight line by linearregression and the resulting equation used to arrive at projectionsof future arisings per head. These have been combined withprojections of future employment in the manufacturing and businesssector, obtained from the Census and Statistics Department, toproduce a projection of the future total privately-collected arisingsof household, commercial and industrial waste. This projection,which does not include chemical wastes that by 2001,4840tonnes of privately-collected wastes will require disposal each day.
B2
T3ci
CD•s03
0
1O0J2r»
33
CL
O
I(83a
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
-
— _. - - " " -
Quantity ,.--"'
• f,--.'
J*^~*
*~*^f Arisings/head ^~--'~"'~""jc .— ~~ *"** ~"*
.r ^ * -V" ~""'"~Jig***** 'if. * -~ "*
x^x^#. -* -*" *" " * Average growth rate 3.3%
*
i • i • i • i ' i • i • i • i ' i f I • I . • l • i * i i
155
>>03
1.00 ?0CL03
0.75 "5.030u.
0.50 a
0.251974 1978 1982 1986 1990 1994 1998 2001
Year
Figure B.1 Forecast of publicly collected waste
6,000
•q£ 5,0000)
ra| 4,000CD
0
0 3,000
| 2,000
0
| 1,000O
0
1
By GDP/
X* ''
^By employee'
Quantity ^^^'^l A . .,-v^' •.---"By HistoricaL
y:^''~^~*~** Trend
y* Arisings/employee __^- -^* - " '_
- // " - ^j^——"*
"^ -5,- - "*"* * Average growth rate 5.8%
I ! I I I I I I ! I I !! I I ! I I I I I I I
979 1983 1987 1991 1995 1999 2001
3,0 S
Q2.0 fc
0.
0
1.0 |[E
LJJ
0OL
Year
Figure B,2 Forecast of privately collected waste
CONSTRUCTION WASTE
2-5 Past arisings of construction waste are presented in FigureB'.3. Since the 1986 T 1988 arisings include a substantial quantityof building debris which could be diverted to public dumps, the 1986- 1988 figures should be adjusted before using them as the basis forprojection. These figures have been fitted to a straight line bylinear regression and the resulting equation used to calculateprojections of construction waste arisings up to the year 2001*Based on this procedure, the projected construction waste arisings in2001 will be 5630 tonnes per day.
DREDGED AND EXCAVATED WASTES
2.6 The annual arisings of dredged and excavated wastes for thepast ten years are presented in Figure B.4. There is no clear trendand consequently the historic data cannot be used as a guide tofuture requirements-. An assessment of large scale developmentprojects to be carried out in the territory in the next few yearswhich are likely to produce large quantities of spoil requiringmarine disposal has, however, been made, ..Based on the assessment itis estimated that a minimum of 30 x 10 m of spoil requiring seadisposal will be generated from those committed reclamation projects*It is anticipated that a number of large scale reclamation projectswill be carried out in the next ten years, in particular thoseprojects arising from the Port & Airport development study (PADS),and this will result in a substantial increase in the arisings ofdredged and excavated wastes.
DIFFICULT WASTE
Sewage sludge ;
2.7 The large scale development of the New Territories in areaswhere the disposal of raw or primary^treated sewage would be at bestunacceptable and at worst impossible, has led to a considerableincrease in planned sewage treatment capacity* A number of newsewage treatment works will be built in the coming years, many ofwhich will provide secondary sewage treatment and will therefore giverise to sludges requiring disposal in far greater quantities than atpresent.
2-.8 The projected arisings of sewage treatment works sludgesare presented in Table B.I. The projections are based on the plannedprogramme for the construction of new treatment works and on theassumption that the works will operate at their design capacitieswhen commissioned. There will be some variation in the capacity ofthe plants to dewater the sludges produced'. Hence the variations inpercentage dry solids indicated in Table B<.1<- A review of the sewagestrategy is being conducted and this review may result in changes tothe future planned arrangements for sewage treatment and hence apossible increase or decrease in the sludge disposal requirement.
TJd.^*,&CO05
O
10O
wO
7,000 -i
6,000 -
5,000 -
4,000 -
3,000 -
2,000 -
1,000 -
linear regression to obtainprojected arisings for the period,from mid 1 990's onwards ..-•''
j_ _j _j_ | | i | f — | | | I H I I I H i I I I I I
1979 1983 1987 1991 1995 2001Year
Note: Projected Arisings based on past year figures whichare adjusted to exclude building debris.
Figure B.3 Forecast of construction waste
03
$,
CD,-
CO
OD5
"5.
3-'Q•D<D
HI
20
18
16
14
12
10
8
6
4
l • ; ' ; . . . . i .. n i T^ i r1978 1980 1982 1984
Year1986 1988
Figure B.4 Quantities of dredged and excavated materialdumped between 1978 and 1988 inclusive
- B5 -
Table Bsl Projected future arisings of sewage sludge (tonnes per day)
Year
1991
1996
2001
Source Areas
Sha Tin(157, d-.s-.)
133
171
208
Tai Po &Fan ling(30% d.s.)
84
103
103
Other(17%-35%d.s.)
70
249
249
Total
287
523
560
d.s. = dry solids
Water works sludge
2.9 Water works sludges are currently discharged either to coastalwaters via long sea outfalls or directly to water courses. They aretherefore not included in the waste monitoring programme. However it isconsidered that disposal of the sludges to water courses is notacceptable and in future some other means of disposal will have to befound* The rate of production of water works sludge in 1988 wasapproximately 4000 t.p.d'* Increases in water treatment works capacityare planned for the future and these will give rise to additionalquantities of sludge requiring disposal. Based on existing and plannedfuture capacity for water treatment the quantities of sludge that willrequire disposal in the future have been calculated and are presented inTable B'.
Table B»2 Projected future arisings of water works sludge(tonnes per day)
Year
1991
1996
2001
Source Area
Sha Tin(1% d.s.)
3,200
3,200
3,200
Tai Po & North(1% d.s.)
320
390
800
Other(1-6% d.s.)
1,500
2,450
2,550
Total
5,020
6,040
6,550
d.sv = dry solids
- B6 -
2,10 The present arisings of sewage works screenings and grit,which amount to 40 t.p.d* are equivalent to approximately 70 kg per1,000 m of daily flow. The current planned treatment capacity isfor an average dry weather flow of approximately 2.3 million m perday. This being so, the arisings of screenings and grit can beexpected to increase to 160 t.p.d. by the year 2001.
Excrement a 1 waste
2.11 Arisings of excremental waste are likely to increase in thecoming years as toilet facilities in rural recreational areas and invillage sites are improved and as greater emphasis is placed on theproper maintenance and regular desludging of septic tanks. Estimatesof increases in septic tank sludge arisings have been made up to 2001on the basis of planned septic tank construction in the NewTerritories and a collection rate of 80%. The estimates thusobtained are presented in Table B.3.
Table B<*3 Projected future arisings of septic tank sludge(tonnes per day; 4Z d«s«)
Year
1991
1996
2001
Source Area
Sha Tin
25
26
29
Tai Po &Fanling
46
48
53
Other
93
100
100
Total
164
174
182
Livestock waste
2*12 The disposal of livestock waste was brought under controlwith effect from 24 June 1988 through the provisions of the WasteDisposal Ordinance (Cap. 354). The effect of the implementation ofadequate control will be to stop livestock keepers (pig and poultryfarmers) from discharging untreated livestock waste into watercourses. Livestock keepers in certain (banned) areas will, beprohibited from keeping livestock* Those in other(controlled), areasintroduced in a phased manner will have to choose between ceasingoperation, treating, the wastes on site to an approved standard, orhaving them removed, treated and disposed of elsewhere in a propermanner* ' '•:••'•':'• '•-'"•;'.:•.'•••>.••:.'..;: • • • ' : , .•/ • • ' . ' • ' ' •/'/:':"". • • • ,: ' • • ' . • • • • • :
- B7 -
2.13 Four basic options for treating wastes are available to thefarmers. Briefly these are :
(a) Dry muck out - In this method faecal matter is removedbefore hosing out; faeces may be either fully composted,partially composted, or disposed of directly to the land asfertilizer or to fish farms; urine and washwater may bedischarged to a soakaway or further treated to provide aneffluent that can be discharged to a water course*
(b) Wet muck out - In this method faecal matter is not removedbefore hosing out and the hosed out slurry must becontained. There are three means of treatment and disposalof the slurry :
i) on-farm treatment giving rise to effluents which canbe disposed of to a water course and sludge whichmust be collected and disposed of elsewhere; and
ii) off-farm treatment - essentially as (i) but wastesmust be collected and treated centrally; and
iii) land application - the liquid manure can be disposedof directly to the land for agricultural orhorticultural purposes or to fish farms.
(c) Pig-on-litter - In this method, approximately 250 mm ofsawdust mixed with a special bacterial product is used asa bedding material for pig raising* The pig waste isabsorbed, decomposed and stabilized as it is evenlyspread and mixed with the bedding material by manualoperation and the movement of pigs*
(d) Hybrid system - This is basically a combination of thedry muck-out and wet muck-out methods whereby the feacalmatter is partially removed whilst the residual waste ishosed out for treatment.
2.14 The onus will be on the farmers to choose the appropriatedisposal method and there is therefore some uncertainty concerningthe quantities and types of waste that will need to be disposed of.However based on research carried out by consultants and by theEnvironmental Protection Department it is estimated that as a resultof the new restrictions 30% of the farmers will go out of business.Of those remaining it is estimated that approximately 7070 will choosethe dry muck out method and the remainder will choose the wet muckout method. It is not possible to say at present what proportion ofthe dry muck out waste would be fully composted and what proportionpartially composted as this will depend on whether a market for thecompost can be developed.
- B8 -
21. 15 It is Intended that controls on livestock waste be phasedin over a 9 year period from 1988. About one half of the wastearisings will be brought under control in the first three-year phaseand most of the remaining waste arisings will be brought undercontrol by the end of the second three-year phase. Bearing this inmind, and on the basis of the estimates of the proportions of farmersusing different treatment methods the projected livestock wastearisings up to the year 1996 have been assessed and are presented inTable B',4. The quantity produced in 1996 is presumed to representthe terminal rate of production.
Table B*4 Projected future arisings of livestock wastesrequiring collection and disposal (tonnes perday; 15X
Year
1988
1989
1990
1991
1992
1993
1994
1995
1996
Waste Type
Solids(dry muck out)
189
225
272
397
491
508
518
518
518
sludge(wet muck out)
14
15
18
26
33
34
35
35
35
d.sv = dry solids
- B9 -
Animal carcasses
2r«16 Since the populations of stray animals (chiefly dogs andcats) are kept under control the growth in the number of animalcarcasses requiring disposal is likely to be linked to the growth inthe human population and the propensity of that population to keeppets, the number of imported animals, and also to any changes in thelivestock rearing industry. It is not possible to make anyprediction concerning the former but the numbers of carcasses of pigsand poultry requiring disposal should be reduced by about 30% whenthe livestock waste control scheme is implemented. For planningpurposes it is presumed that the daily arisings will amount to around8 tonnes in 2001.
Abattoir waste
2.17 The arisings of abattoir waste are linked directly to theconsumption of fresh meat within the territory which in turn islinked to the size of the population* It is possible that as livingstandards rise even more fresh meat will be consumed daily and thegrowth in abattoir wastes will therefore exceed the rate of growth ofthe population. For planning purposes it is assumed that abattoirwaste arisings will no more than double in the next 15 years and thatin 2001 the daily arisings will be no more than 70 tonnes* It shouldbe noted that the estimate mainly relates to the quantity expected tobe disposed of at landfills*
Condemned food
2'. 18 There is no means of assessing likely future arisings ofcondemned food. Such arisings are likely to increase in the futureas more food is brought into the territory to service the needs ofthe increasing populations Possibly the rate of increase will exceedthe rate of population growth if, as a result of increasingaffluence, the per capita food consumption increases. For planningpurposes however it is assumed that the daily arisings will no morethan double over the next 15 years and therefore the amount requiringdisposal in 2001 will be no more than 30 t.pyd.
CHEMICAL WASTE
2.19 Prediction of future arisings of chemical wastes isextremely difficult because to do so means taking into account thelikely future expansion and/or contraction of each of thewaste-generating industries* Nevertheless consultants commissionedby the Environmental Protection Department have made an assessment offuture chemical waste arisings based on trends within the industries,movements in production rates, changes in employment patterns, andpurchases of raw materials* Their estimates of future chemical wastearisings upto 1997 are presented in Table B*5. The estimates do not,and c annot, take into account any possib1e technological developmentsthat might result in a change in either the quality orwaste produced.
- BIO -
Table B.5 Projected Ar is ings of Chemical Waste In 1992 &
Waste
Acid
Alkali
Copper containing waste Acidic spent PCBa etchant
solution Alkaline spent PCBa etchant
Copper waste solution fromother factories
Zinc containing waste solution
Nickel containing waste solution
Other metal salts containing waste solution
Cyanide containing solution
Non-chromium bearing oxidizing agents
Chromium bearing oxidizing agents
Halogenated solvents
Non-halogenated solvents
Phenols and derivatives
Polymerization precursor and production waste
Mineral oil
Fuel oil
Oil /water mixtures
Pharmaceutical products
Mixed organic compounds
Mixed inorganic compounds
Miscellaneous chemical waste
Interceptor & treatmnt Plant sludge
Tank cleaning sludge
Tar, asphalt, bitumen and pitch
Tannery waste
-., . - : Printing waste • .' : ' ' . ' . • : ': : ; : . ' : . ' " ' . . . ;.'•• • , .".'• " " , , : /• • " • , • . , • : • .
Dyestuff wastes
Plating bath sludges
: Paint wastes . ;.' ; ' . ; ;' : •.,''.;'' ' . : ' . • ' • ' • . ' ' • • '." ' "••' '' " ' • . • ;. •'••'-,'.."• ' ':' • "'•
Waste catalysts
: . ./Total";-;." ' . ; ' . ' ' . ' . . • • ' •/'• ' . ' '/'.' . • • • , ' • ' . • • ' "' . • : • ' . ' . ' . ' ; . " "::':;/ .;" - . ' ;, • . '
1997 (Units in tpa)
1992
22,000
42,000
) )) 19,000 )) )
150
13
140
1,300
130
11
59
1 , 700
1,800
2.2
42
5,700
51
13,000
1
140
74
32
42
1,000
140
400
•.', ' ' • • • • • • . -;" " 9 3 • ; " . • '-'
59
•••••••'••••,." 11 " ' ' / .'-
700
' . . ' . ' • ' • ' ; . . ' ',4;;,., - ' . • • ' . ' • ' ;
110,000
1997
25,000
50,000
25,000
160
14
160
1,400
160
12
68
2,000
2,100
2.4
44
5,900
53
13,000
1
150
78
35
44
1,000
150
400
94
52
12
750
•. • „ .- . 4 • . : • • ';.
130,000
PCB stands for Printed Circuit Board,
Notei All figures rounded up to 2 significant figures.No projections have been made for MARPOL arislngs due to the very wide range of possibilities•
- Bll -
CLINICAL WASTE
2.20 Estimation of future arisings of clinical waste isextremely difficult, partly because of a lack of historic data andpartly because of the difficulty of predicting the likely rate ofprovision of private medical facilities. It is the intention thatall new medical facilities should incorporate purpose-builtincinerators and this should obviate the need for any additionalcollection of clinical waste by the collection authorities. Howeverthere will probably be a growth in the number of private doctors1
surgeries and clinics which would not possess adequate waste disposalfacilities. To ensure an adequate safety margin in assessing wastedisposal needs it is assumed that clinical wastes requiring specialcollection in 2001 will be up to 10 tonnes per day.
RADIOACTIVE WASTE
2<.21 Like chemical wastes, prediction of future arisings ofradioactive wastes is very difficult because the generation of suchwastes depends very much upon developments in industry. Recentlyhowever the quantities of such wastes generated by industry have beendeclining as the waste-producing industries have themselves declined.There may be some increase in the rate of generation of radioactivewastes from medical establishments but broadly speaking the situationis unlikely to change greatly in future years.
PULVERISED FUEL ASH (PFA) AND FUENACE BOTTOM ASH (FBA)
2.22 The sole producers of PFA and FBA are the electric utilitycompanies. Projected future arisings of PFA and FBA are thusdependent on
(a) the growth in the demand for power in the territory; and
(b) the continued use of coal as fuel for the power stations.
Both Hong Kong Electric and China Light and Power have made acommitment to the continued long-term use of coal as a fuel for theirpower stations. They have produced their own projections of futureproduction of PFA and FBA based on their plans for increases ingenerating capacity and upon their own projections of growth in thedemand for power. Projections provided by both companies of thefuture production of PFA and FBA are presented in Figures B.5.Production of PFA by Hong Kong Electric is projected to rise toapproximately 400 Kilotonnes per year in 2001. The correspondingfigure for FBA is 100 Kilotonnes per year in 2001. Production of PFAand FBA by China Light and Power is projected to rise to 1030 and 114kilotonnes per year respectively in 2001. These projections are verybroad estimates and may be subject to variations. For China Lightand Power, projections for 1997 and subsequent years assume thedevelopment of new coal-fired power generation facilities in HongKong'.
B12
1,600 —i
1,400
1,200 —
PFAACTUAL PRODUCTION
FBAACTUAL PRODUCTION
Upper estimate
(+10%) ...
PFA
Jg 1,000 —
CDCLwc 800
•o
C/33O 600 —
,, Lower estimate(-10%)
400 —
200 —Upper estimate
(+10%)
FBA
Lower estimate(-10%)
i r r i i i I I
1985 1987 20011986 1988 1990 1992 1994 1996 1998 2000
Year
Note: Estimated arisings of PFA are conservative
Figure B.5 Projected total arisings of PFA and FBA
- B13 ,-•-
PROJECTED TOTAL DISPOSAL MQUIREMENTS FOR MUNICIPAL WASTE
2,23 Based on the foregoing (i.e. a direct extrapolation of pasttrends and/or best estimates of likely future arisings), if currentpatterns of waste disposal are maintained in the future this willgive rise, in 2001, to a land-based disposal capacity requirement ofapproximately 16730 tvp-.d'. This is the figure for projected futurearisings of household, commercial, industrial, construction andmarine collected wastes (grouped as municipal waste)*
CONTROL TOTAL FOR MUNICIPAL WASTE
2'. 24 The projected future arisings of publicly-collected waste(i*er« principally household waste but including street waste and somecommercial waste), privately-collected waste (i.e. commercial,industrial, and some household waste) and construction waste havebeen obtained by extrapolating past trends. ,,.The_J.mplicit: assumptionbehind these estimates there fore J s thaj:_ %^&rns_^of ^a.st.e generat ionwi 11 cont inue_ in ^ the future a long the .SMae J-lnesj-s JElHXj ^past. ThJ^s^as^sumption may well be unreasonable, especially forconstruction waste which is likely to depend,^cruciaTlylupAiilJEEk.economic activity of the territory and policy decisions made by thegovernment regarding such matters as public housingconstruction,urban redevelopment and new town development. In view of theuncertainty surrounding the estimates it is considered advisable tocheck the predictions against a control total derived by other means.
2-. 25 _It is weJJ._jdocquantity of wast£ .arisings is ejscrjLbaibJ.em s f §_funct^on_of^ asociety's wealth, as indicated by its gross domesticjgroduct_^GDP).Hong Kong is no exception. Figure B.6 is a plot against GDP of thecombined annual arisings of municipal waste'.
2.26 Thus if future GDP can be predicted with reasonableaccuracy this will provide a means of establishing a separate controltotal for future arisings of municipal waste'. Projections'of GDPgrowth rate are produced regularly by the C&SD for planning purposes.In the medium terra (upto 3 years) these are based on an econometricmodel and in the long term (upto 2006) on the projected increase inthe labour supply and the projected increase in productivity. Theformer is obtained from population projections and the latter from anexamination of trends of productivity in the different sectors of theeconomy.
2.27 The projected GDP growth rate is 6<.0% p.a. upto 1992, 5.6%for the period 1993 to 1996, 5.2% for the period 1997 to 2001, and4-.97* for the period 2002 to 2006. In order to draw comparison withthe projected arisings based on past trends as mentioned inpara. 2.23, the projection based on GDP growth is produced byexcluding all building debris from the arisings data. On this basis,a projection of future waste arisings has been obtained and ispresented in Figure B-. 7-.
B14 -
18 i-
16 -
14 -
coCD
I 1213
ca<oo£ 10<oO)c
"(0
8.1Q 6
Export quantity of waste
materials included in the total
84
4
88
87
Export quantity of wastematerials excluded from the total
60 100 140 180 220 260 3xlO
80 120 160 200 240
Current Year's Total GDP (HK$ million)
Figure B,6 The combined annual arisings of waste as a function of GDP
3!•- f*
3P3
~TIq
SaaI
- -S :: :o"O"JB,
i1SJ§/•
CDCOcr
1Q.O
0Otr
CQ0
Quantities of Municipal Solid Waste(thousand tonnes per day)
— L -0. ~i -i -A |\
CO O N) 4^ O) 00 O
O 00 ~~CD vw
g" S~| 51-* C Q. CD
|||| g _to co o o
O -3gTo^S<o co -- _^
m m O COO ^H 5> -n <Q=i ® eo"3 co"0 - § 0 ic . :co o ^2- —^ o> O"O
. . . . . . l.|i| 1 s~i1?®
" ''? c b ' S S - "2 2f CO* — *
ill S ~SJ o --.
fs -- D.§'-" ^
§• • • * • " " • • • •
,~. : . ..,
• i-
J i l l i
'">
co co oo ^r^'• ^ **s| %j& CO t^ j
o o ts> "°> ""*" o
C.TI » • fr*
^ ^ o? S-OPP CD• £> 0>
" "
xN^
'X'••-..x
'••...
'X.
- B16 -
The predicted quantity of municipal solid waste projected on thebasis of GDP growth is 18,560 t.p.d. in 2001. This projection,although it does not match closely with the projected estimate of16730 t.p.d. based on past trends, does provide a usefulcross-reference for future planning.
GEOGRAPHICAL DISTRIBUTION OF FUTURE WASTE ARISINGS
2»28 Projected increases in population and in manufacturing andcommercial sector employment have been obtained for each wastearising district and used to project future arisings of publicly- andprivately-collected waste in each districts The projected futurewaste arisings thus obtained, aggregated by region, are presented inpictorial form in Figure B.8. The projections indicate that therelative quantities of waste arisings in Hong Kong show a slightincrease over the planning period. However the relative quantitiesof wastes projected to be generated in the New Territories show amuch larger increase in the next decade, with a correspondingdecrease in the relative waste quantities in Kowloon. The projectedarisings of construction waste show further increases in 1991.However, a decrease is observed from the mid 1990fs onwards, sincevarious measures being pursued to reduce the quantity of inertconstruction waste requiring landfill disposal would likely bringabout such a decrease in the long ternr.
Bl?
HONG KONG ISLAND
,44%
18%18%
38%
47% 56% 54%
1988(2347 tonnes)
35% 22%
1991 1996
23%23%
2001
KOWLOON
18% 29%20%
29%
53%
1988(5790 tonnes)
NEW TERRITORIES
20%
37%
54%
1988(4744 tonnes)
Publicly Collected Waste
27%
36%37%
1996 2001
34% 30%
34%
34% 36%
1996
Privately Collected Waste
2001
Construction Waste(excluding buildingdebris for1996 and 2001)
Figure B.8 Projected future waste arisings by region and by type
- Cl -
APPENDIX C
ENVIRONMENTAL PROBLEMS
ENVIRONMENTAL PROBLEMS POSED BY EXISTING COLLECTION ARRANGEMENTS
3.1 Adverse environmental impacts associated with thecollection of waste, whether by the public or private sector, arisefrom
a) odour both from points where the waste accumulates prior tocollection and from vehicles used for collection;
b) non-containment of leachate at points where wasteaccumulates prior to collection and in vehicles used forcollection;
c) noise generated by the waste collection process;
d) dust generated by the waste collection process; and
e) littering along collection routes and at collection points*
3*2 In respect of the refuse collection services run by thecollection authorities the main problems are (a),(b) & (c).
3.3 For vehicles, the odour problem can be kept under controlby good housekeeping, specifically by ensuring that they areregularly and vigorously cleaned* At present the exterior of eachRCV is washed two or three times a week using high pressure waterjets, brushes and detergents, and plans are in hand to installautomatic drive-in/drive-out washing facilities at a number of depotsthroughout the territory which will allow almost daily washing* ForUSD vehicles the tailgate unit, body floor, and side panels insidethe body are washed 6 to 8 times a month. But for RSD vehicles theinterior and the tailgate unit are washed much less frequently, atbest once or twice a month and at worst only when a service or repairis required. As long as this is the case the problem of odour fromcollection vehicles will persist.
3.4. Permanent RCPs where appropriate incorporate facilities to.reduce the odour problem. These include activated carbon filters andvehicle exhaust extraction systems. They also include water pointsso that the walls and floor may be hosed down after every operation,and roller shutters which allow odour to be contained whenever the•RGP is not being used. Temporary RCPs on the other hand do not haveextraction systems, nor adequate washing facilities and are notenclosed. Consequently they remain a source of odour nuisance, _especially during the summer months. Washing down of temporary RCPsis carried out by street cleansing vehicles and where drainage - ^systems are inadequate this can result in blocked drains and pollutedstreets a n d gutters. ."••/, ".;••'" • • • . ' / ' • ' . . ' • ' . . ; • . . Y . : : . • • • . . " . . • • • . • • • ' . • • . •
C2 -
3.5 In the context of waste collection, ffleachatefl is the termused to describe water which has percolated through and/or beensqueezed from refuse. Leachate generation is particularly severewhen refuse which has become exceptionally wet (perhaps through beingleft exposed to rainwater) is loaded into RCVs. The problem ofleachate at RCPs can be kept under control by regular washing of theRCP. The greater problem concerns leachate in vehicles which may bedeposited on the road anywhere along a vehicle's route if it is notproperly contained.
3.6 All RCVs operated by the collection authorities haveprovision for leachate storage, either by original design within theloading hopper and underbody runoff tanks, or by subsequentmodification* USD and RSD staff are under instructions to drain offleachate at each RCP immediately after loading has been completed,and at the final disposal site. Spillage in the street may occur ifthe sump is not drained prior to embarking on a journey, if the sealson the vehicle are poor, or if drivers do not handle the vehicleswith the specific objective of avoiding leachate spillage. A furtherproblem is that drain pipes on the leachate sumps are liable tobecome blocked so that leachate spillage may occur even if goodoperating practices are adopted.
3.7 For purpose-built RCVs the means of controlling theleachate problem lies in adequate staff training and procurement ofvehicles with effective seals and appropriately designed leachatesumps incorporating trouble-free drains.
3.8 Noise is associated with all traffic movements and theoperation of virtually all machinery. The collection andtransportation of refuse is no exception. Noise generation is one ofthe factors taken into account by the collection authorities whenprocuring vehicles and every effort is made to ensure vehicles do notgive rise to a noise nuisance.
3*9 In the private sector, odour, leachate, noise, dust,, andlittering are all significant problems. However because the privatesector generally collects waste from premises with their own storagefacilities, and because this generally means collecting large numbersof loads of relatively small quantities, the problems that arise tendto be associated more with collection vehicles and practices thanwith storage prior to collection*
3.10 The majority of vehicles used in the private sector forwaste collection are not designed for handling waste in anenvironmentally acceptable manner. The vehicles usually have nomeans of leachate containment and where waste collected consists ofsubstantial amounts of putrescible material leachate spillage l salways a serious environmental nuisance, especially during the rainyseason. Because the vehicles are frequently not enclosed they oftenleave a trail of litter along the routes which they ply» Generally,little effort is made to ensure that vehicles used are notexcessively noisy.
- C3 -
ENVTRONMEOTAL PROBLEMS ASSOCIATED WITH WASTE TREATMENT AND DISPOSALFACILITIES
Landfills
3.11 Generally the existing landfills suffer from the followingenvironmental problems, although not every site suffers from all ofthem -
(a) inadequate odour control;
(b) inadequate gas control;
(c) inadequate leachate control; and
(d) differential settlement.
(a) Odour
3*12 Odour from refuse is inevitably associated with any wastedisposal facility* At landfills it arises from two sources namelyvehicles delivering refuse to the site and the site itself * In HongKong these problems are experienced at every site but at JordanValley the problem of odour from the site itself has be.en broughtpartially under control by ensuring
a) that a cover of inert fill is spread on the refuse two orthree times a day instead of only at the end of the day;and
b) that the refuse is disposed of in narrow tipping bays andlaid in relatively thin layers so that it can be wellcontrolled and compacted and the area of the tipping facekept to a minimum*
There is, however, no gas control and gas is also an odour source.At the other landfills cover- is provided only at the end of the dayand the practice of using narrow bays and tipping in thin layers isnot followed.
(b) Gas
3%,13 Gas is produced by all landfills containing organic waste.It is the result of the biological decomposition of refuse andconsists mainly of methane and carbon dioxide, generally in theproportions 50 - 60% to 50 — 40%.' The gas is flammable and, undercertain conditions, explosive* Depending on the quantities of tracecontaminants, particularly those of sulphur compounds, it may also bemalodorous*
~ C4 -
3.14 At Hong Kong landfills, arrangements to vent the landfillgas have been made by inserting into the waste cell a number ofperforated pipes through which the gas may escape into the open air*There are two major problems associated with dealing with landfillgas in this manner namely : -
a) the pipes tend to become blocked, bent or broken by naturalmovement of the landfill so that their efficiency as gascollectors is greatly reduced, with the result that gaswhich is unable to escape moves sideways or downwards intothe surrounding soils and escapes through fissures innearby rock faces; and
b) when moderately efficient gas collection does take placepotentially explosive conditions are created in a zone atthe mouth of the venting pipe where the gas mixes with air.
This practice is not acceptable environmentally and has now beendiscontinued, and action is in hand to evaluate alternativearrangements at selected sites. The construction of any newlandfills must incorporate adequate gas collection systems.
(c) Leachate
3<*15 In the context of landfills, leachate is the term used todescribe water which has permeated through the waste cell. It is asolution and suspension of inorganic salts and the products ofdecomposition of the refuse* Its precise composition depends largelyon the nature of "tie wastes placed in the landfill, and theconditions of decomposition (e*g* whether aerobic or anaerobic,mesophilic or thermophilic). It is a potentially highly pollutingsubstance as it may contain salts of heavy metals in solution and mayexhibit both a high biochemical and a high chemical oxygen demand.Of particular concern is its potential to pollute groundwatersupplies*
3.16 In Hong Kong leachate collection systems are installed onlyat the inland landfills, that is Jordan Valley and Pillar PointValley* Each of these landfills possesses a network of collectingdrains-. At Pillar Point Valley the leachate passes into the seweragesystem, from which it is discharged into the Urmston Road waters* JVt^Jordan Valley it passes into the foul sewerage system and is "eventually discharged into Victoria Harbour via the Kwun Tong^ IliBSl"?!??! and submarine outfall* At the marine sites (that is,at *§huen Wan and Junk Bay Stage I) there has in the past been littleattempt to control leachate flow and disposal. At Shuen Wan thereare a number of sumps in which leachate is collected before soakingaway through an earth bund into Tolo Harbour* JkL. Junk .Jay.- these- is,np , deslgned sump and .leachate tends to pond and accumulate in variousRljaSfisJt>JBhind.tfce. sea wall* It then" permeates through the sea wall ;
bS*£Jthe^^ This situation is "environmentallyundesirable, particularly at Shuen Wan where the leachate dischargesinto the serai-enclosed waters of Tolo Harbour* However in accordance
- C5 -
with the original project scope action is now in hand to construct apermanent sea wall around the landfill, behind which will beinstalled leachate interception drains. The leachate will becollected and pumped to Tai Po sewage treatment works for treatmentprior to disposal. For all future landfills, whether at inland ormarine sites, the possible need to incorporate leachate containmentand treatment systems will be addressed in a comprehensiveenvironmental impact assessment.
(d) Differential settlement
3.17 All landfills suffer to a greater or lesser extent fromsettlement caused by the weight of the upper layers of materialgradually compacting the lower layers, and by the decomposition ofrefuse within the waste cell. At a landfill site at Gin Drinkers1
Bay which was formerly operated as a completely %conj plled opendump, settlement ranging from 0.3 m to 3 m has been recorded overperiods ranging from 21 to 66 months, long after the tip had beenclosed. In addition, differential settlement occurs when the degreeof compaction or the composition of the lower layers of refuse is notuniforms This leads to an uneven ground surface and tends to damageany installed services, utilities or building structures* Clearlydifferential settlement of this nature greatly reduces the usefulnessof the site once the landfill has been completed.
3.18 Other problems that might be expected at landfills aregenerally of little significance in Hong Kong* Four of the existingfive sites are in relatively remote areas so noise is not usually aproblem-. Pests and vermin are kept well under control by thepractice of covering the refuse with inert fill and by regularspraying with pesticides and rodenticides* Bird nuisance problemsare minimal.
Municipal incinerators
3'. 19 Due to their locations, the existing municipal incineratorsrepresent aserious source of air pollution in the urban area and ahealth risk to those living or working nearby. The major concern isnot the more conventional pollutants they emit, such as particulates,chlorine, carbon monoxide and oxides of. sulphur and nitrogen,although these too represent a problem; the major concern is thatthey emit, also, from time to time, quantities Qf .jLlgfiix toxIicT'"substances such as dioxins and heavy metals which,even in tracequantities, represent a serious health hazard.
3.20 Whilst it is possible to minimise the emission of the moreconventional pollutants by standard air pollution control technology(at a cost), this is not the case with the toxic substancesmentioned. To eliminate the toxic emissions would require either therebuilding of the present incinerators so as to incorporate the verylatest hijgh^tempewture emission control technology (at vast expense)or to remove the, materials that give rise to the toxic substancesbefore they are burnt'., This latter option is not practicable,however, as it would entail sorting all of the refuse by hand priorto incineration to remove the offending materials, which includebatteries, PVC products, spilled or packaged insecticides, etc.Neither option is therefore realistic'.
- G6 -
3^21 This is not to say that all municipal incinerators would beunacceptable from an air pollution point of view. An incineratorthat is well designed, maintained and operated and which is situatedin a well ventilated area reasonably remote from major centres ofpopulation or agriculture would not pose significant air pollutionproblems. The present municipal incinerators, however, do notsatisfy all of these criteria and pose a definite health risk. Theincinerators at Kennedy Town and Lai Chi Kok are of particularconcern as their plumes often impinge upon residential properties.The Kwai Chung incinerator, being more modern and slightly bettersituated, is of relatively less concern but is also not acceptablefrom an air pollution point of view*
3-22 Although the more serious air pollution problems from thepresent incinerators are intractable, action has been taken at leastto reduce the level of particulates emitted by installingelectrostatic precipitators to the chimneys of the incinerators.Precipitators are already fitted to the Kennedy Town and Kwai Chungincinerators as well as Station A of the Lai Chi Kok incinerator.The effect of the precipitators when correctly operated andmaintained is to significantly reduce the quantities of particulatematter emitted, thereby greatly reducing the visible pollution fromthe incinerators* The only practical way to overcome the moreserious air pollution problems, however, is to phase out the existingincinerators.
Chai Wan. piilverisatioiJi plant
3f*23 Environmentally the main problems with the plant in bothits past and present use are odour and scattering of refuse by thewind during barge loading* The sources of odour are the refusereception chamber and the barge onto which refuse is loaded. Thebest way to overcome the problems would be to containerise the wasteprior to loading onto the barge.
- Dl -
APPENDIX D
EVALUATION OF ALTEHNATIVE DISPOSAL OPTIONS
4-1 For convenience the discussion of future possiblearrangements for the treatment and disposal of wastes will be dividedinto a discussion of methods to be used for municipal waste which iscurrently disposed of mainly to landfill, difficult waste, and otherwastes for which special arrangements are made (dredged and excavatedsoils, PFA and FBA, and chemical wastes)'*
MUNICIPAL WASTES
4.2 Options for dealing with the arisings of municipal waste(which includes mainly household, commercial,industrial andconstruction waste) may be divided into those entailing treatmentand those entailing disposal. Treatment methods are characterised bythe fact that after processing there will always remain some wasteresidue requiring disposal-. Treatment processes include
a) all resource recovery methods;
b) incineration; and
c) transfer.
Disposal methods are those methods entailing the final disposal ofwastes and are restricted to
a) landfill 5
b) dumping at sea; and
c) discharge to coastal waters down long sea outfalls (for afew wastes only).
4.3 The divisions between these two categories are not hard andfast. Incineration, for example, is effectively a disposal method.for 70%.of its waste intake since this proportion of the intake isdischarged to the atmosphere after combustion. Landfill, on theother hand, has the potential to operate as a resource recoverymethod if gas generated within the waste cell is collected and used.
Treatment methods • • ' • . • • " • • ; . • • • ' •'•• ' . • : ' • " . • . ' . • ' . " ' . '''; . /;:'' ' - " • : : . " • . . • ' ' • .
(a) Resource recovery
4.4 Resource recovery is here taken to mean the processing ofparts of the waste stream to yield re-usable products such as energy,
~ D2 -
fuel or specific materials. It should not be confused withrecycling, which is taken to be the separate collection andprocessing of specific waste types for rapid sale or re-use (e.g.collection of aluminium beverage cans and subsequent export ofaluminium metal). The complexity of resource recovery methods rangesfrom composting, which involves a relatively simple technique for thestabilisation of organic refuse by bacteria, through processes whichare aimed at the production of fuels from refuse, to full scaleresource recovery which involves the separation and processing ofvarious fractions of the waste stream to produce usable products. Inthe context of planning for waste disposal in Hong Kong, resourcerecovery methods suffer from a number of disadvantages as follows
(i) they usually require substantial investment in plant andmachinery and tend to be expensive;
(ii) they may involve processes which have not yet beenadequately proven; one potentially attractive resourcerecovery method is pyrolysis (the thermal decomposition oforganic material in the absence of oxygen to produce liquidor gaseous fuels) but unfortunately most pyrolysisprocesses appear to have been tested only on a laboratoryor small pilots-plant scale; experience on near-commercialscale is very limited and certainly not sufficient to beable to recommend the method for treatment of Hong Kong'swaste;
(iii) the viability of resource recovery methods depends uponuses or markets being found for the materials recovered;experience with the Ghai Wan composting plant has shown howdifficult it can be to ensure that the product recovered ismarketable; and
(iv) invariably with resource recovery processes, a substantialresidue of waste remains which still has to be finallydisposed of; the amount requiring final disposal may beexpected to range from 20 to 40% of the intake but ifattempts to find markets for the products fail, up to 100%of the intake may require final disposal; the ChaiWan composting plant is again a case in point.
4.5 Perhaps the most important of the above disadvantages are(i) and (iii)y Resource recovery methods are in fact littledifferent from any manufacturing process'* They involve theprocessing of a raw material (waste) to produce products (e»g.metals, compost, liquid and gaseous fuels) for which outlets have tobe found. To reduce the costs of the recovery processes the productsneed to be marketed and sold. Otherwise the recovery process willhave no significant advantage over straightforward disposaltechniques. If the public sector were to adopt resource recovery asa means of waste treatment the cost to the community would be likelyto depend upon the efficiency with which the plants were operated andthe skill with which the products were marketed and sold.
- D3 -
Marketing and selling of products recovered from waste are not areasin which the public sector has any great expertise* This, coupledwith the other disadvantages of resource recovery methods leads tothe conclusion that such methods should only be adopted by the publicsector if
(i) any financial costs are likely to be outweighed by socialand environmental benefits;
(ii) there are good arguments for developing the technology atpublic expense; or
(iii) there is some strategic value in the recovery of a specifictype of wastes
In the context of Hong Kong only one waste type, livestock waste,justifies public sector involvement in resource recovery methods.
4v6 Although public sector involvement in waste treatmentprocesses based on resource recovery is considered to be unwise, thisdoes not mean that proposals from the private sector to set uptreatment facilities based on resource recovery would be discouraged.On the contrary such private sector initiatives are to be welcomedand, as far as is practicable, supported'.
(b) Incineration
4'. 7 Incineration is a method of treating and disposing of wastematerials by controlled combustion* It includes an element ofresource recovery in that waste heat is frequently harnessed to allowthe generation of electricity. However its primary purpose is thedestruction of waste. Globally it is probably second only tolandfill as a method of waste treatment and disposal. In Hong Kongit is the method used for the treatment of approximately 38% ofcurrent domestic waste arisings.
4'.8 On the technical and environmental side incinerationsuffers from a number of disadvantages as a method of waste treatmentand disposal. These are as follows :~
(i) it is limited to combustible wastes so that a suitablerepository still has to be found for non-combustiblewastes;
(ii) it does not dispose of waste completely; a residueconstituting 21 ~ 28% dry weight of the refuse burned, and5-7% of the volume, remains to be disposed of afterincineration; and
- D4 -
(iii) it has the potential to be a major cause of air pollution.
4.9 Against the disadvantages there are a number of advantagesnamely :-
(i) a relatively small area of land is utilised;
(ii) when the facility reaches the end of its useful life thelanduse of the site is not restricted as it is in the caseof a landfill; (a similar plant or other replacementfacility would, however, have to be provided elsewhere);
(iii) it offers a means of recovering energy from waste by usingthe refuse as a fuel for an electricity generating system;
(iv) it offers a. means of recovering certain materials (e.g.ferrous metals) from waste with relative ease; and
(v) notwithstanding the fact that a residue remains to bedisposed of after the waste has been incinerated, thereduction in volume (approximately 9470) and the qualitativechange in the nature of the material requiring finaldisposal, mean that scarce landfill resources can beconserved and the waste can be more easily dealt with.
4*10 The most significant of the disadvantages is the potentialfor air pollution. Measures that could be taken to reduce thepollution problem significantly fall into two broad categoriesnamely -
(i) those aimed at reducing the quantity of pollutants emittedfrom the plant; and
(ii) those aimed at ensuring sufficient dispersal of pollutantsso that receptors are not adversely affected; such measurescan include siting of the facility as well as design.
4<. 11 The measures in category (i) include the installation ofelectrostatic precipitators to remove particulate matter and theinstallation of tfgas scrubbing1' equipment which aims to removepolluting gases. Gas scrubbing in particular is expensive and thetechnology is at a relatively early stage of development. In bothcases, but especially in the case of gas scrubbers, furtherquantities of wastes may be produced which require subsequentdisposal. Two out of the three Hong Kong incinerators possesselectrostatic precipitators (the exception is Lai Chi Kok whereelectrostatic precipitators have been fitted to station A only).None possesses gas scrubbing equipments The efficiency of theelectrostatic precipitators is generally in the range 94 to 99%.
- D5 -
4-. 12 Enhanced dispersion and dilution of pollutants can beachieved by ensuring incinerators are built in areas where there isusually good air movement and little potential for emissions tobecome trapped close to ground level, and by building tall stacks.Unfortunately Hong Kong offers few opportunities for pollution fromincinerators to be ameliorated in this manner. Much of the landsuitable for constructing incinerators is in valleys where airpollutants are likely to be trapped. Over much of the remainder is aproliferation of high rise housing on which any effluent plume from astack of 75 m or less is likely to impinge. Given the topography andbuilding construction in Hong Kong it has been suggested thatincinerator stacks should be as much as 200 m in height. Over muchof Kowloon however, such a stack height would fall foul of airportflight path height restrictions which, over the Kowloon peninsula,range from about 45 m above PD to about 120 m above PD. Conceivablysuitable sites could be found in the New Territories butconstruction of an incinerator at a site remote from the centre ofwaste arisings would result in considerably increased transportationcosts.
4.13 To summarise, the advantages that incineration has to offeras a method of waste disposal mean that it must be seriouslyconsidered* However if it is to be used as a method of wastedisposal in Hong Kong in the future, steps must be taken to ensurethat the environmental impact is minimised. This would probablymean, at the very least, installing both electrostatic precipitatorsand gas scrubbing equipment. In addition it may be necessary toconstruct unusually high stacks to ensure adequate dispersal anddilution of flue gases and, possibly, to construct incinerators onlyin remote areas. The cost implications of these measures are suchthat if other alternatives are available they are likely, in mostinstances, to be preferred.
(c) Transfer
4*14 Waste transfer is a waste treatment technique that effectsvirtuallyno reduction Inwastemass andis aimed primarily atreducing the costs of transporting waste to a point of finaldisposal. The concept involves the construction of a number ofstrategically - located transfer stations close to the centroids ofwaste arisings. Vehicles which have collected waste from the pointof arising deliver it to a transfer station where it is transferred,with or without treatment, into a larger vehicle for haulage in bulkto a final disposal facility. The large vehicle may be a lorry, ifroad transport is utilised, or a barge if transport is to be by sea.A transfer station may include facilities for the compaction of wasteto increase the payload of the bulk transfer vehicles. A furtheradvantage of using a transfer station to treat waste prior to finaldisposal is that it provides the opportunity for waste to becontainerised prior to haulage to a final disposal site. This wouldhelp to reduce considerably the problem of odour and drippingleachate during transportation. If direct discharge of waste tocontainers were to be adopted odour would also be reduced at thetransfer station itself'.
- D6 -
4'. 15 Transfer stations, like any other waste treatment ordisposal facility, have the potential for generating a number ofadverse environmental impacts. These include
(i) traffic congestion;(ii) noise from generated traffic;(iii) plant operation noise;(iv) odour;(v) dust;(vi) polluted washwater and leachate production, and(vii) litter.
The effects of these impacts can be reduced or eliminated byappropriate preventative and/or curative action. Proper planning andconsideration of road capacities should ensure that a transferstation is not located in such a position,,, or constructed to such asize, as to give rise to significant traffic congestion. Plant andtraffic noise can be kept to a minimum by ensuring that all vehiclesand machinery are properly silenced and the plant is constructedaccording to stringent noise control standards* Dust can be kept toa minimum by ensuring that the plant is enclosed and that suitablebarriers (such as rubber curtains) exist to prevent dust from thetransfer operation escaping to the outside and causing a nuisance.Regular water spraying can also be carried out to keep dust levelsdown. Polluted washwater can be dealt with by provision ofappropriate drain connections to a foul sewer. Litter and fallingrefuse could be kept under control by good housekeeping and byrefusing to accept waste from private sector waste collectionvehicles in which refuse was not properly contained. (Any suchvehicles refused entry would have to go to a landfill to dispose ofthe waste. Appropriate enforcement measures would have to beimplemented to ensure the waste was not dumped illegally).
4,16 The biggest potential problem with a refuse transferstation is probably that of odour. To control odour it would benecessary to operate a fully enclosed plant possibly with appropriateodour extraction systems'. It would also be necessary to ensure thatvehicles arriving at or leaving the plant were not themselves a causefor complaint. This would mean requiring that all vehicles be washedregularly, both inside and out, and that all vehicles used for thecollection of waste be of such a construction that the waste isproperly enclosed. Apart from steps taken to control odour at sourcethe most effective way to reduce the impact of odour would be toensure the stations are not located close to residential areas.Other potential problems include bird nuisance and proliferation ofvermin-* The former does not appear to be a problem in Hong Kongwhile efforts should be made to keep the latter under control by goodhousekeeping and conducting regular pest eradication exercise.
4* 17 Whether or not transfer stations are adopted as a method ofwaste treatment In Hong Kong depends upon
(i) whether incineration is a viable option; and
(ii) what the final disposal method is likely to be and wherethe final disposal sites are likely to be located.
Disposalmethods
4.18 A means of final disposal of waste will always be necessaryno matter what treatment and disposal strategy is adopted. Ifresource recovery or incineration were to be adopted there would haveto be some way of getting rid of the residues remaining aftertreatment. For certain wastes, such as construction wastes, there ~\/are few treatment options available and some means of final disposal .) :will always be necessary to cater for these. - •'
<a) Landfill
4.19 The two main advantages of landfill as a means of finaldisposal are
(i) that it can be used for almost every type of waste; and
(ii) that it is relatively cheap.
4.20 The main problems associated with the use of landfill as ameans of final waste disposal have already been described in AppendixC in relation to existing Hong Kong landfills. If advantage is to betaken of the relatively low cost of landfill as a disposal method itis important that steps should be taken to reduce odour to anacceptable level and contain and control any gas or leachategenerated. It is also important to ensure that the land can be putto reasonably productive use shortly- af t erJuh&_jsi.tei s exhausted.
4.21 To summarise, the continued use of landfill as an optionfor disposal of Hong Kong's waste is feasible and desirable. Howeverany future landfills established must include measures to ensure thatodour and uneven settlement are minimised and gas and leachateproduction are properly controlled. The cost of including thesemeasures need to be considered when formulating a definitive wastedisposal strategy.
(b) Dumping at sea
4.22 Dumping of waste at sea is a very simple method ofdisposal as it involves little or no treatment of the waste.
D8 -
In practice, however, it can be considered acceptable only for alimited number of waste types. Any waste which might float (e.g.domestic waste with paper and plastics, building wastes containingwood) cannot be dumped at sea because of the aesthetic effects andthe navigational hazards that would arise. Neither can waste whichwould sink, but which would introduce significant quantities of toxicsubstances into the marine environment'. Sea dumping is, in effect,suitable only for the disposal of :-
(a) material that sinks, is non-toxic and will not present ahazard to shipping; and
(b) material that is non-toxic and will dissolve and dispersereadily in sea water.
In other words sea dumping is a feasible disposal option only forsludges, excavated and dredged soils and certain soluble chemicals.
(c) Discharge to coastal waters
4.23 This method of disposal involves the pumping of wastes downpipelines running from the point of arising on shore to a distanceup to several kilometres off shore. It can only be used forsemi-solid or liquid wastes. In the context of the waste disposalplan this means sewage and water works sludges and chemical wasteswhich happen to be liquids or sludges. These wastes are consideredin later paragraphs.
4.24 To summarise, it is concluded that for municipal wastesdisposed of by the public sector only those treatment and disposalmethods which do not incorporate a substantial element of resourcerecovery should be adopted* For household, commercial and industrialwaste, this effectively means that treatment is limited toincineration and/or transfer, and final disposal to disposal at alandfill. Construction waste, is not suitable for treatment byincineration or transfer'. Nor is it suitable for final disposal bydumping at sea. It is clear therefore that for the majority of HongKong's waste the only feasible final disposal method is disposal tolandfill. Incineration and transfer may also be used to conservelandfill resources and/or reduce transportation costs , the precisebalance of facilities depending up the balance of costs and' ' ' '
DIFFICULT WASTE
4.25 For the "difficult" waste,, possible treatment and disposalmethods are somewhat more varied* It therefore needs to beconsidered on a type-by-type basis.
- D9 -
Sewage sludge
4.26 Options available for the treatment or disposal of sewagesludge are
(i) landfill;
(ii) sea dumping;
(iii) discharge down a long sea outfall;
(iv) incineration; and
(v) use as a fertiliser.
4<v27 Discharge down a long sea outfall has to be ruled outbecause of the likely impact of a large amount of sewage sludge onnearshore coastal waters. Use of sewage sludge as a fertiliser wouldnot be appropriate for Hong Kong mainly because
(a) the relatively limited amount of land under agriculturecould not absorb a sufficient quantity of the sludgeproduced; and
(b) the vegetable growers in Hong Kong typically need amultiplicity of fertilisers for different vegetables grownin different seasons and sewage sludge would not be a goodfertiliser for use in this context'.
There is also the potential problem of contamination of soils byheavy metals, some of which are found in relatively highconcentrations in Hong Kong's sewage sludge. This leaves landfill,incineration and sea dumping as possible disposal options.
4.28 A comparison of the costs of these three options hasindicated that for sludge arising at treatment works which are inclose proximity to moderately deep water sea frontage, dumping at seais about 60% cheaper than dewatering followed by disposal atlandfill, which is in turn about half the cost of dewatering followedby incineration. On the basis of this cost comparison and asubsequent detailed feasibility study by consultants it has beenconcluded that action should be taken immediately to arrange for thedisposal at sea of all stabilised sewage sludges generated at the ShaTin Sewage Treatment Works, with the option of extending thisdisposal plan at a later date to sludges arising in Tai Po and NorthDistricts.
4'.29 Disposal of sludge at sea is not without environmentalproblems* Possible adverse effects include promotion of algalblooms, deoxygenation of the water column, increased turbidity,smothering of the sea bed and accumulation of persistent pollutants(such as heavy metals and some non-degradable organic compounds) inmarine food chains* However the site selected as the dumping ground
- DIG -
has good dispersal characteristics and there is no reason to believethat the assimilative and dispersive capacity of the area will beexceeded by the dumping of sludge at the quantities proposed. As asafeguard against the possibility that the dumping programme mighthave adverse effects the government has established a comprehensiveenvironmental monitoring programme. A major baseline study of thephysical, chemical and biological characteristics of the area iscurrently being carried out. There will be a limited survey in 1991and further comprehensive surveys will be carried out in subsequentyearsv The environmental effects will thus be monitored regularlyand a major review will be conducted after five years1 operation witha view to deciding whether dumping should be allowed to continue and,if so, whether the quantities dumped could be increased so thatsludges from Tai Po and North districts could be included.
4.30 For sewage sludges arising in areas not in close proximityto a suitable waterfront, disposal will have to be to landfill. Thesludge will first have to be dewatered and disposal carried out insuch a way that it will not produce operational difficulties at thelandfill or localised leachate, gas, and settlement problems. Priorexperimentation will be necessary to determine the best way of mixingsludge with other refuse in order to avoid these problems.
Water works sludge
4.31 Water works sludge is completely different in characterfrom sewage sludge. It arises from the use of alum as a coagulant toremove fine silt, chemical residues and organic material frompotentially potable water and is consequently a gelatinous,relatively inert and incombustible material with a very low (1%)solids content and low concentrations of organic material. Itcontains relatively high concentration of aluminium, iron andmanganese.
4.32 Options for disposal of water works sludge are limited todumping at sea or discharge to coastal waters via a long sea outfall*Since a decision has been made to dump Sha Tin's sewage sludge at seait Is Intended that Sha Tin's water works sludge should be disposedof in a similar manner. As with sewage sludges, the possibility ofdisposing of alum sludge from Tai Po and North districts In the sameway will be reviewed at a later date. Improved methods of dealingwith water works sludges In other areas have not yet been worked out.This problem will need to be addressed separately.
Sewage treatment works screenings and grit ;: , • • •
4.33 These wastes are currently disposed of at landfill. Thequantities Involved are very small In comparison with the quantitiesof other wastes that will continue to require disposal to landfilland it is therefore not proposed that future arrangements fordisposal should differ froro those now employed*.
- Dll -
Excrestental waste
4.34 These wastes are presently mainly delivered to sewagetreatment works for treatment and digestions They therefore are, andwill continue to be, disposed of by whatever method is used forsewage treatment works sludges. In particular excremental wastesdelivered to Sha Tin sewage treatment works for digestion willeventually be disposed of at sea.
Livestock waste
4*.35 When livestock waste is brought under control arisingsrequiring disposal will be in two forms namely sludge and raw manure.However the installation by farmers of facilities for the dewateringof sludge and the deposit of the sludge at a government collectionpoint is likely to be cheaper than having the raw sludge collectedand removed by a contractor. It is therefore anticipated that mostof the sludge would be removed by the government's collectionservice. In view of the relatively small quantities of arisings ofsludge that are projected compared with those of dry muck out wasteand the fact that the moisture content of the two types of waste willbe roughly the same (8570) it would be sensible to dispose of the twotypes of waste together and disposal options are considered on thisbasis.
4 .36 The options for disposal are :-
i) digestion at sewage treatment works with sewage sludges;
ii) disposal to land (i.e. used as a fertiliser);
iii) disposal at landfill;
iv) disposal at sea; and
v) incinerations
Incineration has to be discounted because it is too expensive.Disposal at sea would not be economic on its own but following thedecision to construct facilities for the disposal of Sha Tin's sewagetreatment works sludge at sea it may well be feasible to dispose ofsome livestock waste by this route also, provided it is stablisedfirst, Further consideration has still to be given to thispossibility, and to the possibility of disposing of the wastes bydigestion at sewage treatment works. Disposal at landfill is alsopossible subject to appropriate loading rates being worked out.Research into this latter aspect is currently being conducted by theEnvironmental Protection Department.
- D12 -
4.37 Notwithstanding the fact that other options are feasiblethe preferred option for disposal of livestock wastes is to land, byuse as a fertiliser- For use as fertiliser the wastes will have tobe composted (although farmers following the wet muck out method whodo not wish to use the government collection service mightconceivably dispose of some sludge by direct application to land).The choice of composting as a means of disposal has the added benefitthat the process involves stabilisation of the waste, which would benecessary if outlets for compost could not be found and landfill ordumping at sea had to be adopted.
4.38 The possibility of the government being involved in thecomposting of livestock waste appears to run counter to the generalprinciple that the public sector should not adopt treatment ordisposal methods which result in the production of a material thatneeds to be marketed and sold as a commercial product* However inthis particular instance government involvement is justified. Thecontrol of livestock waste disposal is essential. Livestock wastehas considerable potential as a recovered resource in the form ofcompost as fertiliser. Yet it is unlikely that individual farmerswould have the necessary expertise to develop appropriate compostingtechniques or to develop the necessary market for the product. Bytaking the lead the government may be able
(i) to control the waste;
(ii) to recover a valuable resource; and
(iii) to develop a means of waste recovery that will enablefarmers to recover some of the costs of waste control.
4*39 There remains the possibility however that outlets forcomposted manure will not be found and all the waste, whether fullyor partially composted, will need to be disposed of to landfill*
.Condemned goods,, abattoir- waste and animal carcasses
4.40 For those condemned goods which are in a packaged orIncombustible form (e.g. tinned food), landfill is the only feasiblemethod of disposal. For those condemned goods which are not packagedand which give rise to a health risk (e,g. thawed meat), incinerationis preferable but incineration in this context means cremation i.e*incineration in a long residence time combustion chamber.Incineration in an incinerator designed for refuse would not beappropriate because the relatively short residence time would be1ikely to lead to incomplet e combus t ion * Cremation is a1so requiredfor animal carcasses* At present bad meat and a proportion of theanimal carcasses are cremated at the incinerator at KennedyTown abattoir. Carcasses collected by the Regional ServicesDepartment are disposed of at landfills*
- D13 -
The latter method of disposal is not satisfactory and carries healthrisks as well as being generally offensive^ It is currently carriedout only on a temporary basis. On the other hand the abattoirincinerators were designed to cater only for the destruction of anydiseased animals brought in for slaughter and were not intended toserve as a general facility for the disposal of carcasses of farmanimals and pets. Consequently it would not be appropriate orpossible to use the abattoir incinerators for this purpose on a longterm basis.
4.41 Reprocessing at by-product plant is also a possible option,in particular for the large arising of abattoir waste. Abattoirwaste which cannot be economically reprocessed is difficult to handledue partly to its offensive nature. Incineration is feasible butspecial arrangements would be required to allow some dewatering priorto incineration and to facilitate handling* In view of therelatively small quantities of waste generated such facilities cannotbe justified and disposal to landfill is therefore the mostappropriate option for the future.
OTHER WASTES
Dredged and excavated wastes
4 .42 There are only two alternatives for the disposal of thesewastes viz :
(i) landfill; and
(ii) disposal at sea.
Very large quantities of these materials are produced each yearwhich, if disposed of to landfill, would result in a greatlyaccelerated depletion of landfill capacity and considerable leachateproblems. In addition, as much of the material is dredged from thesea bed, transferring it to land would serve little useful purposebut would incur substantial additional expense. The preferred optionfor disposal of these wastes is therefore marine dumping.
Clinical waste
4.43 Clinical waste should ideally be incinerated inpurpose-built incinerators in order to safeguard public health*Incineration in municipal incinerators is not appropriate because ofthe danger of incomplete combustion* All future planned hospitals,whether in the public or private sector> should therefore incorporateincinerators with adequate capacity to deal with the wastes produced.The incinerators should be capable of achieving complete combustionof material. It is recommended that for public and private hospitalsand clinics whose incineration capacity is inadequate, the clinicalwaste should be collected and disposed of at a centralised facility,which could incorporate a cremator for handling animal carcasses*'Facility1 in this context could mean a single plant with combustionchambers designed for different waste or designed to operate undervarying conditions'.
- D14 -
Chemical waste
4.44 A wide variety of chemical wastes are generated in HongKong and it is difficult, if not impossible, to recommend a singledisposal method that would be suitable for all of them* Broadly theoptions are as follows
i) dumping at sea, uncontained;
ii) dumping at sea, contained;
iii) disposal to containment site on land;
iv) codisposal at ordinary landfill;
v) recovery and reuse;
vi) chemical treatment prior to disposal at landfill; and
vii) high temperature incinerations
4.45 Straightforward dumping at sea is unacceptable because itwould mean the direct introduction of toxic material into the marineenvironment and would be no improvement on the present situation.Option (ii) might be a possibility for some chemical wastes. Thewastes could be sealed in impermeable, corrosion-proof and shockproofcontainers and dumped off the edge of the continental shelf. Thisoption would be extremely expensive and would always carry the dangerthat containers could be dispersed from the original dump sites byocean currents into areas where they could pose a hazard tonavigation or fishing-. In addition if containers were to leak itwould be impossible to control the resultant pollution.
4*46 Option (iii), disposal to a containment site on land, wouldinvolve placement of the wastes in a specially-designed site isolatedfrom the environment by liners and an impervious cover. This isessentially a method of waste storage and little degradation of thewaste could be expected to take place'-. The site would requirelong-term monitoring, maintenance and supervision, and stringentsecurity to keep members of the public away; In all probability thesite could never be put to any beneficial use once the disposalcapacity was exhausted-*. This is therefore not a preferred option.
4.47 Codisposal to landfill is feasible* This would involve thedisposal of chemical wastes at ordinary landfills receiving municipalwastes. At a codisposal site various natural physical, chemical andbiological processes act to detoxify the chemical wastes so that theimpact on the environment is practically the same as that of alandfill receiving only municipal wastes. The problem withcodisposal is that adequate detoxification depends on mixing a smallvolume of hazardous waste with a large volume of municipal waste*
- D15
There is also the added problem that different types of chemicalwaste would need to be kept well separated from each other at thecodisposal site, further reducing codisposal capacity. Because ofthese problems it has been decided that codisposal should not beadopted as a general solution for the disposal of all hazardouswastes but should only be used for the disposal of wastes for whichother means of disposal (e.g. recovery and reuse; chemical treatment,incineration) are inappropriate.
4.48 Recovery and re-use of some chemicals, chemical treatmentof others and incineration of others are feasible. In view of theneed to conserve codisposal capacity it has been decided to establisha chemical waste treatment centre on Tsing Yi Island incorporatingall these treatment methods. After treatment there would remain aneed to dispose of residues. These would be disposed of at landfillsby mixing with municipal waste. Studies are now in hand to establishthe mixing ratios necessary to obtain the complete attenuation of anychemical wastes deposited at a codisposal site.
Radioactive waste
4.49 Existing methods of disposal of radioactive wastes aregenerally adequate. There is a possibility that some wastescurrently disposed of by storage underground could be dealt with bycodisposal at a landfills This may allow for the establishment of asmaller, purpose-built, long term storage chamber. A separate studyhas been initiated to investigate these possibilities.
PFA and FBA
4.50 In addition to the current methods of disposal of PFA andFBA (ive. lagooningy and sale on a commercial basis) the otheroptions for disposal are
(a) disposal at sea;
(b) land restoration (for example, old quarry); and
(c). reclamation'.
Disposal at sea is not a favoured option for three reasons. First, aproportion of PFA consists of vitrified, hollow spheres which willfloat and which may hence produce a problem of pollution of surficialwaters Second, when deposited in bulk in seawater physico-chemicalreactions lead to the formation of amorphous "concrete11 lumps.
- D16 -
If these were to accumulate on the sea bed they could present anavigational and fishing hazard. Third, PFA and FBA are relativelyrich in concentrations of potentially toxic heavy metals. Deposit ofthese in a concentrated manner on the sea bed may pose a threat tomarine life and, through possible concentration through the foodchain, a threat to public health.
4.51 Land restoration and reclamation are potentially usefulmethods of disposal but it is as yet unclear whether they are bothfeasible and practical. Studies are currently under way to examineboth feasibility and practicality.
4.52 Existing methods of disposal are proven. Lagooning issuccessful and will continue to be used in the future. Sale of PFAand FBA on a commercial basis is the preferred option but it isquestionable whether sufficient outlets can be found to accommodatethe projected future increase in production.
4.53 To summarise, the preferred option for disposal of PFA andFBA is sale on a commercial basis, followed by lagooning if saleoutlets cannot be found. Use of PFA and FBA in land restoration andreclamation is to be investigated as a possible long-term solution tothe disposal problem^
- El -
APPENDIX E
THE WASTE MANAGEMENT MODEL (WMM)
5'. 1 The Waste Management Model (WMM) is a computer-basedplanning aid employed to develop a cost effective waste managementplan-*
5*2 The WMM consists of the following interactivesub-models/data bases:
(a) Waste arisings sub-model: calculates all existing andprojected future waste arisings by type and geographicalarea.
(b) Transport network sub-model: calculates average journeytimes and distances between waste sources, treatmentplants, disposal facilities, vehicle depots etc. using asimplified principal road network; different road networksfor different planning years, based on existing developmentplans, are stored in the sub-modelv
(c) Transport cost sub-model: calculates transport costsassociated with various transport methods and equipmentusing output from the transport network sub-model and dataon the capital and operating costs of waste-collectionvehicles, including barges and private contractors'vehicles.
(d) Facility cost data base: contains cost data for theconstruction of existing and potential facilities (e.g.incinerators, landfill sites, transfer stations) and theiroperation at a number of feasible capacities.
(e) Allocation sub-model: allocates wastes to facilities atminimum cost, either in total or, if required, at minimumcost to a specific sector (e.g. Urban Council and RegionalCouncil costs, private contractor costs).
(f) Strategy assessment sub-model: summarises the costimplications of a particular strategy for each of theagencies involved in waste management (USD, RSD, EMSD,CESD, private sector etc*).
(g) Plan evaluation sub-model: evaluates the total costs ofthe selected strategies over the full planning period.
5t3. it should be noted that in order for the computations to becarried out it is necessary for the user to specify which facilitiesare available and also to define the time period under study. Anoutline of the way a run on the model is conducted in order to arriveat a costing for a particular strategy will make this clearer.
- E2 -
5-. 4 The user first defines the time scale over which thecalculations are to be made, say 15 years, and divides the time scaleinto a number of shorter time periods (say, 2 years each) to allowfor more flexibility in strategy selection. He also selects thetype(s) of waste under consideration and one of a number of forecastsfor future population and employment in Hong Kong, on the basis ofwhich projections of future waste arisings are to be calculated. Themodel then computes the quantities of wastes of the selected typethat are predicted to arise in each of the selected time periods fora number of pre-defined source areas, based on the forecastpopulation and employment statistics*
5.5 The user then specifies, for each time period, the existingand potential facilities (i.e. transfer stations, other treatmentplants, final disposal sites and refuse collection vehicle depots).The model calculates the costs of transporting each type of wastefrom source areas and facilities to each destination by theappropriate means of transport* Also calculated are the costs ofprocessing or disposing of waste at each specified facility, takinginto account both capital and operating costs'. The model thencalculates, for each time period, how best to assign wastes from thesource areas to the facilities available so as to minimise the costto one or more sectors.
5.6 The user must then assess the configuration proposed by themodel* In doing so he will wish to consider the feasibility of theproposed configuration, especially in relation to possibleenvironmental impacts'. He may also wish to investigate how therecommended configuration would change if the economic and financialvariables were altered (evg. population and employment projections,transport costs).
5.7 The user may also assess other strategies by changing thespecifications of facilities available in each time period. Forexample he may alter the maximum or minimum treatment capacity of anincinerator or transfer station. ¥hen a number of other strategieshave been assessed, and comparisons made, the user eventually arrivesat a strategy which is cost-effective, feasible and environmentallyacceptable, the costs of which are relatively insensitive to moderatevariations in the assumptions. (It must be emphasised however thatthe costs of the different strategies generated by the model areprimarily for comparative purposes and cannot be considered asaccurate predictions of the actual costs for any particularstrategy),
5*8 The WMM has been employed in examining options for thefuture provision of transfer stations in combination with the finaldisposal facilities-. Restrictions applying to the modelling exerciseare :-
(a) Projections of future waste arisings - Projections offuture population on a geographical basis (i.e. district bydistrict) are at present available only upto the year 2001.
- E3 -
Consequently It has not been possible to compute detaileddistrict-by-dlstrict projections of waste arisings after2001 on which to base provision of treatment facilities.The model has therefore been used to examine options fordealing with Hong Kong's waste only upto 2001.
(b) Site availability - Firm sites for transfer stations havenot been identified in all areas where they might berequired. For options which involve the construction oftransfer stations in areas where sites have not beenidentified it has been necessary to presume that sites inthe general area will be found at some time in the future.
(c) Site capacity - The difficulty of obtaining suitable sitesmeans that there is only limited flexibility as to thecapacities of the treatment facilities and the timing oftheir construction* Capacity is limited by site size androad access, and the timing of construction is determinedas much by when the site becomes available as by theprojected need for additional capacity.
- Fl -
APPENDIX F
ESTIMATED CAPITAL AND RECURRENT COSTS OF PROPOSED MAJORWASTE MANAGEMENT FACILITIES
ProjectCapital Cost
$ million
AverageRecurrent Cost$ million p*a«
Kowloon Bay Transfer Station 152 35
Island East Transfer Station 183 38
Island West Transfer Station 106 19
Shatin Transfer Station 82 19
Yuen Long Transfer Station 60 15
West Kowloon Transfer Station 144 20
West New Territories Landfill 1308 35
North-east New Territories Landfi l l 1407 35
South-east New Territories Landfi l l 1364 35
Chemical Waste Treatment Centre 410C
Centralised Incineration Facility
for Special Wastes
2.4
Total 4830 664
Footnote :
a'\inclusive of capital cost repayment over a 15 year period
