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Industrial Wastewater
1
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Industrial Wastewater
The water or liquid carriedwaste from an industrial processThese
wastes may result from
any process or activity ofindustry, manufacture, trade
orbusiness, from the developmentof any natural resource, or
from
animal operations such asfeedlots, poultry houses, ordairies
The term includes contaminatedstorm water and leachate fromsolid
waste facilities
Waste material (solid, gas orliquid) generated by acommercial,
industrial ornonresidential activity
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What is pollution?
Pollution means
!changesin thephysical, chemical and biological characteristics
of
air, land and water
harmsfor the human and other living species, and,!degradationof
the ecosystems
"""the undesirable state of the natural environment being
contaminated with harmful substances as a consequence of
human
activities
#or e$ample, Water Pollution refers to contaminantsin
aquatic
ecosystems (streams, la%es, etc) which render them un&t for
a
particular use"
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Pollutants can reach:
1" 'ir
" Water
" *olid waste
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Water standards:
Drinkable
Recreation:swimming, fshing.
Irrigation
Water impurities may or may not be harmful+ it depends on
The amounts and nature of these impurities,
The ne$t use to which the water will be put, and
The tolerance of these impurities for the ne$t use"
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Types and characteristics of wastewaters:
Contaminants Reason for importance
Physical suspended solids They can lead to the development
ofsludge deposits"
Chemical biodegradable
organics
When discharged untreated to theenvironment, they lead to the
depletion of
natural o$ygen resources"
Nutrients If discharged, they can lead to waterpollution"
a!ardous ecause of their characteristics(e"g",to$icity,
-ammability) are dangerousfor human health and the environment"
ea"y metals They can negatively impact uponbiological waste
treatment processes"
Dissol"ed inorganic solids They are result of water use, and
mayhave to be removed if the wastewater is to
be reused"
#iological pathogens .ommunicable diseases can betransmitted by
the pathogenic organism in
wastewater"
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Water standards
Industrial e$uent standards
Parameter %e&ico a '() b Canada c
*otal suspendedsolids, +mgl-
1/0 1/
#D/, +mgl- 0 /2 1/
p /310 234 2310"/
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What is BOD?
y de&nition, 56 is the quantity of o$ygen required for the
stabili7ation
of the o$idi7able organic matter present over / days
of incubation at 0o
.+ that can be e$plained as a measure of the
o$ygen required by microbes to degrade a sample of e8uent"
The organic content of the water can be estimated by the 56"
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Biochemical Oxygen Demand (BOD)
Definition: The amount of dissolved oxygen utilized by microbes
for
the biochemical oxidation of organic (carbonaceous BOD) and
inorganic (autotrophic or nitrogenous BOD)
The 56 test was developed in 1409s" This is a &ve day test
that
measures the amount of 5consumed in a wastewater sample by
a mi$ed population of heterotrophic bacteria in the dar% at
0o
. 56 of wastewater is typically 1103::0 mg;< and must be
reduced to 0 mg;< for discharge
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56 = 6i> 6f P
where6i= initial dissolved 5concentration
6f= &nal or /3day dissolved 5concentration
P = volumetric fraction of wastewater
?$ample / ml wastewater is added to a 00 ml 56 -as%
P = / = 0"012 6i= @ mg;< 6f= mg; = /4 mg;< 0"012
5$idation is usually 2030A complete after / days
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Total Organic Carbon (TOC)
TOC is measured using a TOC analyzer The sample is combusted
and
organic carbon !uantified using infrared detection
.hemical 5$ygen 6emand (.56)
.56 is measured following digestion at high temperature with
strong o$idant such as chromic acid, or sulfuric
acid;potassium
dichromate" The chromate ion reacts with the .56 producing a
color that is measured"
If .56 BB than 56 what does this meanC
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Why should we minimize the use of water?
Water is such an important part of many manufacturing
processes that we must consider ?8uent Treatment as a
part of the main process because of the great amount
always involved"
Water is abstracted from aquifers and rivers, treated and
supply to industries and homes for diDerent uses+ used
water is supposed to be treated and discharged again into
the rivers" Eost of the times, this water returns to its
natural environment but unfortunately, with a greater
heat content or with some substances added"
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Why should we minimize the use ofwater?
It is also important to minimi7e use of water because of several
reasons
#resh water is often scarce" Figh costs involved operating
e8uent
treatment plants"
6iGcult to separate all the elements that pollute water"
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Industrial pollution problems
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Industrial pollution problems:
The main pollution problems are related to
Increasing use of water for agriculture"
The increase of aqueous e8uent to receiving water"
Population growth" Industrial products and services"
The mental, technical, &nancial, regulatory and
institutional barriers
to implement preventive modern technologies"
R0('1*(:
Ecosystems decline.
Industrialization social costs.
The increase of human diseases"
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Tier 1
The petroleum industry
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The Petroleum Industry:
.rude oil re&ning operations involve e$tracting useful
petroleum
products from crude oil" .rude oil contains fractions of
napthas,
gasoline, gas oils, diesel fuel, asphalt, Het fuel and
lubrication fuels"
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The Petroleum Industry:
Production wastes in the petroleum industry can be grouped
broadlyinto classes
Wastes related to drilling including chemical additives
treatment
and disposal of oil drilling wastes ta%es place either on or oD
thedrilling site"
Wastes related to oil production, primarily produced water
The volume of produced water e$ceeds the volume of drilled
wastes"
If environmental quality standards are not e$ceeded the
remaindermay be discharged to surface waters" The maHority of
producedwater is disposed of underground through inHection wells
and it ispermitted under "*" ?P' control programs"
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What is refinery effluent?
Petroleum re&neries use large volumes of water in their
processes"
The wastewater contains ha7ardous chemicals
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Refinery wastes:
?missions from re&neries include
*ulphur o$ides
Jitrogen o$ides
en7ene, toluene and $ylene
K5.
Wastewater containing 56 levels
Feavy metals
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Pollution )ppro&imate 2uantities
Cooling systems "/3/ mof wastewater generated per ton of
crude"
Polluted wastewater
56 1/03/0 mg;l
.56 003200 mg;l
phenol 0300 mg;l
oil 100300 mg;l (desalted water)
oil /000 mg;l in tan% bottom
ben7ene 13100 mg;lheavy metals 0"13100 mg;l
(olid waste andsludge
to / %g per ton of crude (@0 A should be considered as ha7ardous
wastebecause of the heavy metals and to$ic organic presence)"
3C emissions 0"/ to 2 %g;ton of crude"
thers emissions
TL (en7ene, Toluene and Lylene) 0"/ to 2 g;ton of crude*ulphur
o$ides 0"30"2 %g;ton of crudeJitrogen o$ides 0"00230"/ %g;ton of
crude
Wastes enerated:
(Pollution Prevention and Abatement Handbook World Bank
Group)
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Prorams for reducin pollution
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!o"ernment prorams for reducinpollution:
#or sustainable development, governmental pollution
prevention
programs can best counteract the pressure to invest in Mend
of
pipeN pollution solutions by demonstrating the economic and
environmental bene&ts of a source reduction approach,
ma%ingtechnical information available and providing technical
assistance"
?P' has been wor%ing with industry and government
representing
environmental, community and wor% force issues to prevent
pollution at the source prior to Mend of pipeN treatment"
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!o"ernment prorams for reducinpollution:
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Prorams for reducin pollution:
Eanufacturers could implement a variety of
improved management procedures
that would aid pollution reduction
Environmental audits" Identify (inventory) and correct problems
(strategies
to achieve reductions) that generate wastes"
Regular preventive maintenance" Inspection, maintenance and
replacement of equipment"
Material handling and storage" ?missions of ha7ardous material
must be
avoided" There should be labels of all containers and &rst
aid
recommendations"
Employee training" Well informed employees are better able to
ma%e
valuable waste reduction suggestion"
Operating manual and record eeping" Oood facility
documentation
process procedures, control parameters, ha7ards and operator
responsibilities" Tier 1
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#n"ironmental prorams:
*ome industries may see no diDerence between end of pipe
pollution control and
a front end pollution prevention control"
The importance is that those industries may not go beyond the
&rst stage of waste
reduction"
's the environmental concern deepens, industries have to move
further up the
production chain
?nd of pipe solution to wastes and pollutants+ and later
Internal process modi&cations to reduce emissions and
wastes, and
eventually
edesign products to achieve a ma$imum level of recycling of
raw
materials and minimi7ation of wastes after the products are
used"
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$ome measurements to sa"e water:
4eep water e$uent streams separated.
Reuse water as close to source as possible.
Recycling whene"er it is possible.
#etter control o5 usage with automated systems.
Checking and control o5 leaks.
6hen buying new e7uipment, e"aluate water8e9ciency
models including accessories.
Reducing the 7uantities o5 chemicals so that the amount o5
dilution water will be reduced.
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Reusin water:
It is not only possible but necessary to reuse wastewater of a
process
stream before it leaves the plant accomplished by piping,
diluting
or treating some of the e8uents before using them again"
*ome plants are now using closed systems, so that there are
nowater discharges"
Qero discharges has been practiced in locations where water
is
scarce, and may involve technologies for removing suspended
and
dissolved solids"
.omplete deminerali7ation is relatively e$pensive, however, in
somecases wastewater discharges can be reduced signi&cantly
with
other less e$pensive technologies"
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Treatment processes
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#%pectations of a water treatment proram:
The e$pectations from a water treatment program should be
integrated to include all aspects of the program, from the
proposal
through to the implementation stages"
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Treatment Proram
's we will see in the ne$t diagram, the e$pectations that agood
treatment program should give us are listed below
5verview of a new or e$istent problem"
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Treatment Proram
New orProblem(ystem
Plant(tudy
1ab(tudy
ProposalImplementProgram
ollow8up
New Product*echnology
*ystemundercontrol
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Wastewater treatment processes:
Wastes are generated by every industrial enterprise, and this
wastescan either be liquids or solids"
Wastewater treatment can be divided into three stages
!. "rimary treatmentthat uses physical operations to remove
free
oil and;or suspended solids"
#. $econdary treatmentto remove dissolved contaminants
through chemical or biological action, and
%. Tertiary treatmentfor the removal of residual
contaminants"
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$eparation order
This list shows how separation is carried out
Primary treatment
*edimentation
'eration
*econdary treatment
Tertiary treatment
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Treatments&
Primary treatmentprepares the wastewater for biological
treatment"
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Treatments&
The tertiary treatmentremove speci&c residuals" y
<ration,suspended colloidal solids can be removed+ adsorption
removesorganics by granular activated carbon (O'.)+ and
chemicalo$idation also removes organic compounds"
Tertiary systems have to treat great amounts of wastewater,
sothey are e$pensive"
When streams rich in heavy metals, pesticides or other
substancesthat may pass through primary treatment and inhibit
biologicaltreatment are present, in-plant treatmentsare
necessary"
Precipitation, activated carbon adsorption, chemical o$idation,
air orsteam stripping, wet air o$idation, ion e$change, reverse
osmosisare some of the methods useful when in3plant treatments are
to beused"
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The tertiary treatment&
Tertiary treatment is a polishing step" Its importance is that
rather
than have to &nd solutions at the end of pipe, where primary
and
secondary treatments are used to, it is possible to minimi7e
some
to$ics or ha7ardous components in the process before they
are
combined with other less Mha7ardousN"
iological treatment usually produces a 90;09 e8uent with no
more
than 0 mg;l suspended solids and 0 mg;l 56"
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Tertiary treatment
Fowever, river -ows have decreased owing to drought conditions"
In these
circumstances, new limits are imposed on the quality of the
&nal e8uent"
The treatment processes beyond the secondary treatment to
achieve the
required limits inthe processare well %nown as tertiary
treatments"
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In plant treatment
efore end of pipe wastewater treatment, a program of waste
minimi7ation
should be initiated"
!. Recirculation" In the paper board industry, white water from
a paper
machine can be put through a save all to remove the pulp and
&ber
and recycled to various points in the process"#. $egregation"
.lean streams are separated for direct discharge"
%. &isposal" In many cases, the total discharge 56 and
suspended
solids can be reduced by removal of residue in semidry state
for
disposal"
'. Reduction" The use of automatic cutoDs can reduce the
wastewatervolume"
(. $ubstitution" The substitution of chemical additives of a
lower
pollutional eDect in processing operations"
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"
Tier 1
Wastewater treatment processes:
Process selection
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'iure () *onceptual treatment proram fororanic and to%ic
industrial wastewater
Tier 1
rganicstreams
(treams containing
hea"y metals
%ineralstreams
(ource control
igure ;.
07uali!ation
Neutrali!ationilgrease remo"al
(uspended solids
#iological treatment
inal disposal
#iodegradable"olatile
*o&ic andor
nonbiodegradable
To de&ne the wastewater treatment problems, a preliminary
analysis should be carried out
#or wastewaters containing nonto$ic organics, process design
criteria can be obtained from lab
studies"
(Eckenfelder, 2000)
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$ource treatment:
*ource reduction is any activity that reduces or eliminates
the
generation of ha7ardous wastes at the source
The fundamental goal is to enact changes in consumption, use
and
waste generation patterns associated with products
Tier 1
goal
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$ource treatment:
*ource treatments involves diDerent de&nitions of source
reduction,
but the general consensus appears to be that include any
in3plant
actions to reduce the quantity or the to$icity of the waste at
the
source"
?$amples include equipment modi&cation, design and
operations
changes of the process and products and substitution of raw
materials"
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'iure +) ,aboratory studies for hea"ymetals-"olatile oranics
Tier 1
Prioritypollutants
scan and
bioassay
ed
batch
reactor
1ong8term
biodegradation
Priority
pollutants
scan and
bioassay
07uali!ed
sample
)ir or steam
strippingChemical
o&idation
reduction
Precipitation
(ource
treatment
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'iure .) Treatment of to%ic wastewater:In/plant treatment
Tier 1
Ion
e&change
iltration
Precipitation
&idation
reduction
Polymeric
resins
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0ethods for suspended solids remo"al
Sedimentationis the more common technique in wastewater
treatment because it involves little mechanical equipment and it
is
very stable to operate" Fowever, there are some situations
where
-otation is a better choice"
Flotationis a good technique for solids removal when the
density diDerence between water and the solids is marginal, or
thesolids have a high fat or oil content"
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0ethods for suspended solids remo"al
Coagulationis employed for removal of waste materials in
suspended or colloidal form" .olloids are particles within the
si7e
range of 1 nm to 0"1 nm, do not settle out on standing and can
not
be removed by conventional physical treatment processes"
Precipitation.In the water treatment, the precipitation
process
is used for softening (removal of the hardness caused by
calcium
and magnesium) and removal of iron and manganese"
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'lotation:
6issolved air -otation, which is a common technique" This
technique
basically consists on inHecting an aqueous stream containing
dissolved air into the wastewater " The dissolved air forms
bubbles when it comes out of solution and carries
suspendedparticles, which tend to concentrate at the bubble
wastewater
interface, to the surface, where they form an emulsion"
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'lotation:
Tier 1
Oeneral diagram for -otation methods
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*oaulation:
Paperboards wastes can be eDectively coagulated with low
dosages
of alum" *ilica or polyelectrolyte will aid in the formation of
a rapid
settling -oc"
Wastes that contain emulsi&ed oil can also be clari&ed
bycoagulation"
#or eDective coagulation, al%alinity should &rst be added, "
'fter
addition of al%ali and coagulant, a rapid mi$ing is
recommended"
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1ea"y 0etals Remo"al:
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0)3= %0*)1( R0%3)1 *0CN1
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The Bioloical Treatment
Tier 1
In>uent
wastewater
Physical and
chemical treatment#iodegradable
igh
strength
)naerobic
treatment
Discharge P)C*Inhibitory
Nondegradable
5raction
Polished
e$uent
Dispersed
growth system
Complete mi&
system
Readily
degradable
Nitrogenremo"al
re7uiredi&ed
ow system
(elector
system Polished
e$uent
igh
strength
=es =es
=es
=es
=es
=es=es
No
No
No
No No No
No
(Eckenfelder, 2000)
)hen biological
treatment is
needed+ there
are several
options
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The bioloical treatment: typical operatinparameters and
dimensions
Tier 1
Treatmentmethod
Mode of operationDegree oftreatment
Land requirements Equipment Remarks
Lagoon
Intermittent or continuous
discharge; facultative or
anaerobic
IntermediateEarth dug; 10-60 days
retention
Odor control
frequently required
ctivated
lagoons
!om"letely mi#ed or facultative
continuous basins
$igh in summer;
less in %inter
Earth basin& '-16 ft
dee"& '-16 acres(
)million gal(d*
+ier-mounted or
floating surface
aerators or
subsurface diffusers
,olids se"aration in
lagoon; "eriodic
de%atering and sludge
removal
ctivated
sludge
!om"letely mi#ed or "lug flo%;
sludge recycle
.0/ removal oforganics
Earth or concretebasin; 1"0 ft dee";
2000-320000ft3()million gal(d*
4iffused or
mechanical
aerators; clarifier
for sludge
se"aration and
recycle
E#cess sludge
de%atered and
dis"osed of
5ricling filter!ontinuous a""lication; may
em"loy effluent recycle
Intermediate or
high& de"ending on
loading
2-1700 ft ()milliongal(d*
+lastic "acing 0-
70 ft dee"
+retreatment before
+O58 or activated
sludge "lant
9:! ultistage continuous Intermediate or high +lastic diss,olids
se"aration
required
naerobic
!om"lete mi# %ith recycle;
u"flo% or do%nflo% filter&
fluidiacre*
luminum irrigation
"i"e and s"ray
no
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2d"anced wastewater treatments
'dvanced wastewater treatment is de&ned as the processes
that remove more
pollutants from wastewater than the conventional treatments"
This term
may be applied usually as tertiary treatment, but most of their
goals are to
remove nitrogen, phosphorus, and suspended solids"
'dvanced treatments include .hemical coagulation of
wastewater
Oranular media <ers
ltra<ration
Jano<ration
Wedge3wire screens
Eicroscreening
6iatomaceous earth <ers
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Tier 1
3olume and disposal reduction
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3olume reduction
Kolume reduction can be used to reduce treatment cost and to
reduce handling and disposal costs for residues remaining
after
treatment" Kolume reduction can be accomplished by using a
variety of methods
euse of treated wastewater and wastes
Treatment modi&cations to reduce solid residues
*egregated treatments to reduce ha7ardous waste mi$tures
Incineration to reduce waste volume and to render a
ha7ardous
waste nonha7ardous"
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Reduction of waste production and disposal"olumes
$imple dewatering the sludge is discharged into a series of
tan%s
and allowed to settle" Top water can then be decanted" This
method reduce the volume of sludge for disposal"
/omposting the material is mechanically turned at intervals,
force
aerated and often contained in a building where heat losses,
odor
and water content can be controlled"
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&igestion is the slow degeneration of the organic content
of
sludge by obligate anaerobic bacteria to simpler compounds3
carbon dio$ide, water and anions (nitrate, sulphate,
phosphate)"
6igestion is one of the few sludge treatment processes in which
a
signi&cant reduction of pathogens is possible"
The digestor gas produced is 2/30A methane, 03:A carbon
dio$ide, and traces of sulphur compounds" The collected gas
is
burnt in a boiler to %eep the digestor warm and the e$cess put
to
further heating or power generation purposes"
Tier 1
Reduction of waste production and disposal"olumes
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Reduction of waste production and disposal"olumes
Incineration its main advantages lie in the complete destruction
of
organic compounds, the ash being inert and usually less than
/A
of the original sludge volume"
Eost incinerators are of the -uidi7ed bed variety"
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2 waste manaement diaram&
6astedisposal
6aste
treatment
6aste
recycle
'pgrade
operation
Redesign
process
(ubstituteraw material
Increasing 0?ecti"eness
o5 waste management
