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4.7 Greywater treatment Learning objectives: Get familiar with various treatment options and with the application of various processes Can we remove all.

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Presentation on theme: "4.7 Greywater treatment Learning objectives: Get familiar with various treatment options and with the application of various processes Can we remove all."— Presentation transcript:

1 4.7 Greywater treatment Learning objectives: Get familiar with various treatment options and with the application of various processes Can we remove all the pathogens and heavy metals? What is in the sludge? constructed wetland, gardening, wastewater pond, biol. treatment, membrane- technology Greywater (shower, washing, cleaning, etc.) irrigation, groundwater recharge or direct reuse

2 Application of processes Jan-Olof Drangert, Linköping university, Sweden Physical Chemical Biological B A E D F G BOD, suspended solids BOD, nitrogen, pathogens phosphorus, pathogens, metals C

3 Overview of possible technical options Treatment:Possible technical solutions for greywater: Physical (SS and BOD-levels) Screen, grease trap, septic tank, sedimentation pond Biological I (BOD-level reduction) ABR, anaerobic filter, UASB, soil filters, reactive filters, trickling/bio-filter, stabilisation pond, sub- surface wetlands, irrigation Biological II (N & pathogen reduction) Nitrification-denitrification in wetland or sandfilter, maturation pond, crop production, mulch beds, overland flow Chemical (P, pathogen, metal removal) soil filters, reactive filters, precipitation pond, irrigation Sludge management Thickeners, centrifuge, sieve, fermentation, lime, drainage bed, reed beds, composting, lime stabilisation Karin Tonderski, Linköping univeristy, Sweden

4 Screens and grease traps Organics from kitchen pipe sorted out in a plastic screen Jan-Olof Drangert, Linköping university, Sweden screen Over- flow

5 Sedimentation pond Karin Tonderski, Linköping university, Sweden

6 Sediment Birds eye view Sediment Simple septic tank Scum layer Jan-Olof Drangert, Linköping university, Sweden

7 Anaerobic pond CH 4, CO 2 scum layer sludge Karin Tonderski, Linköping university, Sweden

8 Anaerobic baffled reactor Off-plot system Anaerobic Baffled Reactor (ABR) Pedro Kraemer, BORDA, India

9 Anaerobic Filter (off-plot biogas system) Courtesy of Pedro Kraemer, BORDA, India

10 UASB Reactor Jan-Olof Drangert, Linköping university biogas Air pump

11 o2o2 o2o2 o2o2 o2o2 Horizontal subsurface flow wetlands Influent Main filter filled with graded gravel and sand Cross distribution trench Cross collection trench Outlet shaft Internal water level Effluent Collection and drainage pipe Courtesy of Roshan Shrestha, UN-Habitat, Nepal

12 Construction of horizontal flow wetlands Karin Tonderski, Linköping university, Sweden

13 Soil filters – leachfield or mound systems Jan-Olof Drangert, Linköping university, Sweden

14 Trickling filter Jan-Olof Drangert, Linköping university, Sweden

15 o2o2 o2o2 o2o2 o2o2 Vertical flow subsurface wetland Influent Main filter filled with graded gravel and sand Effluent Collection and drainage pipe Courtesy of Roshan Shrestha, UN-Habitat, Nepal (revised)

16 Biofilter with nozzle distribution Wetland Total area 100 m 2 Courtesy of Thor-Axel Stenström, SMI, Sweden Biofilter and wetland for greywater treatment

17 Common problems in soil filters 1. Overloading (suspended solids, high BOD, water) 2. Uneven distribution (over surface, over clay) 3. Failure in drainage (waterlogging, roots) 4. Wrong choice of sand and gravel (texture, mineral particle shape) Jan-Olof Drangert, Linkoping university, Sweden

18 Improved distribution using controlled clogging Geotextile unit Pre- treatment in sedimentation tank 0.6 m in sand 3 m in silt 10 m Courtesy of Peter Ridderstolpe, WRS. Sweden

19 kitchen Cajete de acolchado Wash room Bath Registro de división de flujos Bird´s eye view of a mulch bed system for a single house Distribution boxes Mulch beds Courtesy of Kim Andersson, Colombia

20 Mulch bed filter 3-10 litres of greywater per m 2 per day Depth max. 40 cm Mulch from garden Entrance with stones Greywater pipe from household Courtesy of Kim Andersson, Colombia

21 Wetland irrigation and overland flow Karin Tonderski, Linköping university, Sweden

22 Extensive Intensive Sorption and irrigation systems - Drain mulch basin - Swales & resorption trenches - Wetland irrigation (overland flow & sub- surface flow, and impounding wetlands) Aerobic biofilters and energy Rapid infiltration systems Soil filters: - Infiltration (open, covered submerged - Sandfilters Artificial filter media: - Indrän, infiltra etc. Biofilter reactors - Trickling filter - Bio-rotors Revised from P. Ridderstolpe, WRS, Uppsala

23 Removal rate of microorganisms in various wastewater treatments (log units) ProcessBacteriaHelminthsVirusesCysts Primary sedimentation: Plain Chemically assisted UASB1-2 Activated sludge Sub-surface flow wetland Aerated lagoon Slow sand filtration/infiltration Disinfection Waste stabilization pond Large variations in practice due to quality of management Sources: WHO, 2006 and Jimenez et al., 2010

24 E: Treatment of sludge - All treatment processes produce sludge, be it much or little -Choice of treatment according to kind of reuse - We need to de-toxify our chemical society New limits on organics proposed under Option 3 from EU (2008) PAH6 mg/kg dry matter PCB0.8 mg/kg dry matter PCDD/F100 ng ITEQ/kg dry matter LAS5 g/kg dry matter NPE450 mg/kg dry matter Limits Cd Cr Cu Hg Ni Pb Zn Old ,100- 1, ,200 2,500- 4,000 New Source: EU, 2008

25 Start from the end ! (centralised example) Our thinking is now on global challenges as well as on local wishes for system performance and status percolating effluent water Dried sludge itself We decide what quality we would like the final products to have. Jan-Olof Drangert, Linköping university, Sweden Sludge drying bed CO 2 & methane gases

26 Pathogen reductions achieved by selected health-protection measures Control measure Reduction (log units) Comments Wastewater treatment 1-4Usually achieved reduction but depends on type and functionality of the treatment system Drip irrigation: - low-growing - high-growing 2424 Root crops and crops such as lettuce that grow just above but partially in contact with soil. Crops such as tomatoes and fruit trees not in contact. Pathogen die-off0.5-2 per day Die-off on crop surfaces between last irrigation and consumption, depends on sunshine, crop type etc. Crop-washing: - with water - disinfection Washing salad crops, vegetables and fruit with: clean water. Weak disinfectant and rinsing in clean water. Produce peeling Produce cooking Fruits, cabbage, root crops. Immersion in boiling or close-to-boiling water. Source: Bos, R., Carr, R. and Keraita, B

27 Environmental and Human health hazards Pathogenic microorganismsChemical compounds Num- bers A few hundreds: handfull unknown added each year 100,000 man-made; Hundreds new man-made added each year Expo- sure In food, by skin penetration, insect bites, in aerosols. - In food, by skin penetration, on skin, in aerosols. Water bodies, soil accumulation Dose- response One up to millions; a few to millions needed for infection Nano- to microgrammes; small amounts that may accumulate. Vulne- rable Humans but not environment. Mainly children & elderly Both humans and environment. All, but particularly babies Barriers Wash hands & veggies, no finger in mouth, heat food, etc Only biodegradable, caution with medicines, effluents to soil Jan-Olof Drangert, Linköping university, Sweden

28 Principle: Organic other solid waste Stormwater sewage Industrial household wastewater Black toilet water greywater Faeces urine Summary of strategies to improve wastewater treatment and nutrient use in agriculture and energy production Jan-Olof Drangert, Linköping University, Sweden


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