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Lettinga Associates Foundation for Environmental Protection & Resource Conservation
Ecosan – some examples of multiple use of household wastewaterAdriaan Mels, Okke Braadbaart, Jules van Lier and Grietje Zeeman
Outline
SWITCH A bit of history on excreta reuse The constraints nowadays What are the recyclable components Examples (Jordan, Beijing, Lima, Sweden,
Netherlands)
Multiple use of municipal wastewater
Linear flow of conventional systems
Circular flow of Ecological Sanitation
SWITCH – Ecological sanitation
Adoption and performance of established (demo) projects
Fate and removal of micro pollutants Nutrient demand around a number of mega-cities Innovative transport systems Technical standards
Adoption and performance
Drivers (and barriers)
Performance (technology selection tool) Public health and environmental protection Resources (re)use Technical performance Financial performance User aspects (acceptance, noise, smell, vermin,
O&M) Robustness
Black water: handle with municipal organic waste
Urine
Grey water: local treatment and use for toilet flush, laundry, car wash, irrigation
Separate collection and use of flows
Urine: use as fertilizer
Distribution of nutrients
Nitrogen (13 g / cap.day)
80%
11%9%
Urine
Feces
Grey water
Phosphorous (2 g / cap.day)
53%
26%
21%
Potassium (4 g / cap.day)
70%
20%
10%
Volume = 1.4 l per day per person on average
Distribution of wastewater flows
Volumes (l / cap. per day)
91.3
34.8
1.5
Grey water
Toilet flush
Black water (urine and feces)
Total 127 l / cap per day (The Netherlands)
Grey water (2/3 of total wastewater) is relatively clean and can be treated locally
2000 2010 2020 2030 2040 2050 2060 20700
20
40
60
80
100
year
‘Available' phosphorus reserves (%)
2% growth
2.5% growth
3% growth
apatite
Source: Driver et al. (2001)
Global depletion of P reserves
Examples of multiple use approaches
Urine re-use in agriculture (Sweden, Peru)
Grey water reuse for toilet flushing and landscaping (Beijing, Netherlands)
Urine is stored for 6 months (to remove remaining pathogens) and is directly used in agriculture
Urine use in agriculture
PERU
OFFICIAL NAME: Republic of Peru CAPITAL: Lima AREA: 1,285,215 km2 COASTLINE: 2,414 kmESTIMATED 2005 POPULATION: 27,925,628
Residual water Latrine
AREA 1 - CENCA
• A pilot project with 55 dry ecological toilets in two human settlements (slums) at the East of Lima, called Los Topacios of Nievería and Casa Huerta la Campiña of Cajamarquilla
AREA 2 - ALTERNATIVA • A pilot project in Ciudad Nuevo Pachacutec in Ventanilla with the construction of:
- 17 water reservoirs of 1500 m3
- 837 public water taps
- 140 ecological toilets + green gardens + rabbits
Baño Ecológico
Sistema de tratamiento
Sistema de riego
AREA 2 - ALTERNATIVA
Fat Keeper
Wetland
No-mix toilet
Men urinal
Green garden
Rabbits
Why area matters for system performanceCENCA ALTERNATIVA
House property Inheritance Donation from government
Middle income (Soles/month) 340 530
NGO involvement after project finished
Yes No
Inhabitants selected sanitation technology
Yes No
Inhabitants designed their toilet
Yes No
Inhabitants paid for the toilet
Yes (only the 40%) No
Tap water Yes No
Toilets close to each other Yes No
Inhabitants manage the system
Yes No
Users identified with the system
Yes No
Brown water
Grey water
Evt. urine
Rain water70 - 100 l /cap. per day
Separate collection and treatment of grey water
Beijing, a rapidly growing city
02468
101214161820
1960 1970 1980 1990 2000 2010 2020 2030
Time
Po
pu
lati
on
(in
mil
lio
ns
)
Source: Bureau of Statistic of Beijing Municipality
… and a very water scarce city
Current water availability is < 300 m3 per capita per year Severe overexploitation groundwater The shortfall between water supply and demand is
estimated to be around 1.8 billion cubic meters by 2010
Wastewater reuse planning
Figure 1. Wastewater reuse planning for the Beijing central region (source: Jia et al., 2005)
Wastewater reuse planningCurrent situation of wastewater reclamation systems
in urban Beijing (note: this does not include wastewater reuse for agricultural irrigation and industrial reuse:
four centralized wastewater treatment plants for reclamation with total treatment capacity of 255,000 m3/day.
300 - 400 decentralized wastewater reclamation systems with treatment capacity of 50,000 – 60,000 m3/day
source: Water Saving Office,2006
‘Management regulation on the construction of wastewater reclamation facilities in Beijing’ (1987)In this regulation the Beijing Municipal Government
issued that: hotels with construction areas exceeding 20,000
m2 and all public buildings with construction areas
exceeding 30,000 m2 should build a decentralized reclamation facility.
As of 2001 also new residential areas exceeding 50,000 m2 fall under this regulation
Five cases presented (of 9 investigated)
BOBO Garden House Residential Area
Beijing Jiaotong University
Xin Bei Wei Hotel
Beiluchun Residential Area
Beijing Normal
University
Item Beijing Jiaotong
University
Beiluchun Residential
area
Beijing Normal
University
Xin Bei Wei Hotel
BOBO Garden House
Residential area
Established in 1993 1999 2001 2002 2003 Influent source Grey
wastewater Mixed
wastewater Mixed
wastewater Grey
wastewater Mixed
wastewater Main treatment technology
Activated sludge
Aerated Ceramic
Filter Activated
sludge
Contact oxidation + disinfection
Contact oxidation + Activated
sludge
Maximal reclamation capacity (m3/day)
200 640 720 120 1,200
Average reclamation (m3/day) 150 600 400 80 3001
Technologies and capacities
1 Another 700 m3 per day are treated and than discharged to the sewer system
Beijing Rainbow Hotel (max. 120 m3 / day)
Wastewater
Grid Bumper tankBiological
contact oxidation
reactorErect
sedimentation tank
Machine filtration
tank
Reclaimed water storage tank
Disinfector
Flocculater adding
machine
Reclaimed water
Buffer tank
Situated in relatively dry area Restrictions on use of ground water Uses approximately 550.000 m3/year municipal
effluent Aim: irrigation of golf courts and supply of water
systems of the park
Use of mixed wastewater in the Efteling, The Netherlands
Centralised wastewater harvesting
Irrigated agriculture accounts for almost 65% of all current water use
Irrigated agriculture water demand is expected to increase only slightly:
Generation of reclaimed wastewater is expected to increase drastically:
1998 863*106 m3
2020 890*106 m3
2001 73*106 m3
2020 265*106 m3
Case Study: Jordan
“It is mandatory that all treatment plant projects must include a fully designed and feasible reuse scheme”
Amman (170.000 m3 sewage/day)
As Samra WSP
Conveyance sewer (40 km)to Desert-WSP system
Conveyance pipeline (40 km)
“Khirbet As Samra” Waste Water Stabilisation Ponds
Actual situation: System loaded with 2 x design flow: HRT = 20 days
Current problems
- Effluent BOD: 150-200 mg/l- Little pathogen removal- Odour problems- High gas production in anaerobic ponds-Up to 15% of incoming wastewater evaporates- Concomitant salt increase
screensgrit
chamber
Raw sewage
high-rateanaerobictreatment
Existing stabilisation
ponds
sludgedryingbeds
Sludge
Research: Implementing anaerobic treatment before ponds
Treated effluent
Anaerobic treatment followed by stabilization ponds
DMW CORPORATION, Japan
Post treatment in pond systems, Bucaramanga, Colombia
Advantage:Combines storage and treatmentRelatively cheap when land is available
Cavalcanti et al. (2003) show that at an HRT of 10 days a removal of 99.99% of E-coli is achieved (i.e. compliance with WHO standards for unrestricted irrigation)
UASB Results “Sewage treatment”
Results two-stage pilot trials Middle East (Jordan):
COD Removal: up to 80% BOD Removal: up to 85%SS Removal: up to 80%Pathogen Removal:
- Coliforms: 70 - 90%- Helminth eggs: up to 100%
Potential CH4 production in Amman(at 170.000 m3 sewage/day): 17,500 m3/day
2 – 2.5 MW