Greywater management to improve water resilience.pptx

greywater management

1. GREY WATER MANAGEMENT Positive Action for Child and Earth Foundation New Delhi, India www.Childrensearth.org Make It Happen

2. Module: Grey Water Management Few Facts about the Water Crisis What is Greywater Hierarchy for handling Greywater Greywater Characteristics Requirements for GW recycling and reuse Options for reuse Technologies available for GW treatment Benefits & Impact of GW recycling Childrensearth.org

3. Facts about Water Use Childrensearth.org

4. Introduction Childrensearth.org L/P/D

5. Circular Water Economy Target hierarchy for handling Grey Water Based on the model of the Circular Economy Avoid Reduce Recycle and Reuse Discharge following treatment Childrensearth.org

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7. GW Characteristics GW is a source of water, energy and nutrients Childrensearth.org

8. Quality Requirements Hygienic safety No comfort loss Environmental tolerance Economic feasibility Childrensearth.org Requirements for GW recycling & reuse

9. Quality Requirements Hygienic safety Microbiological parameters for “service water” (treated GW) in accordance with EU-Guidelines for Bathing Waters : Total coliforms: < 100/ml E. coli: < 10/ml P. aeruginosa: < 1/ml (It is assumed that the bather has full body contact in this water and may occasionally swallow some of it and/or inhale aerosols, and will have no health risk, if the limit values are complied with) In comparison: E. coli in drinking water: 0/100 ml E. coli in bathing water (limit value): 1,000/100ml E. coli in recycled greywater (typical value): 0-10/100 ml Childrensearth.org

10. Quality Requirements No Comfort Loss Physical and chemical parameters which ensure an efficient treatment and storage of the treated greywater without any odours or clogging problems: BOD7 : < 5 mg/l O2 - Saturation: > 50 % UV-Transmission:(254 nm) > 60 % Turbidity: < 2 NTU* The Biochemical Oxygen Demand (BOD) and the oxygen saturation level are the most important quality criteria for the “storage capability” of the treated service water. Low turbidity will cause less depositions in the service water network and a high oxygen saturation will prevent the development of odours . NTU is Nephlometric Turbidity Unit Childrensearth.org

11. Quality Requirements Environment Tolerance Low specific energy demand: ideally < 1.5 kWh/m³ No use of chemicals UV disinfection instead of chlorination Childrensearth.org

12. Quality Requirements Economic Feasibility Investment (including all operational costs) should pay off within reasonable amortisation period Costs for the applied recycling technology should not exceed those for conventional system Lower operating costs can be achieved if high-quality system components are used with low system maintenance and energy demand Childrensearth.org

13. Technical Requirements A pre-treatment stage using self-cleaning sieves should be incorporated in all systems to remove coarse material (hair, lint, sand, metal and plastic parts). If kitchen GW is included in wastewater stream, it is recommended to install a combined grease and sediment trap Space requirement of about 0.1 Sq m per person is representative for biological systems used for GW treatment and primarily dependent on pollution load of GW (GW sources), needed buffer for GW and service water peak flows as well as on required service water quality Systems should be installed such that access to all system parts is possible at all times for maintenance Childrensearth.org Requirements for GW recycling & reuse

14. Installation Requirements Cross connection between potable and non-potable water networks must be checked prior to commissioning (dye test) Labelling of service water (non-potable) pipeworks and tapping points must be done to distinguish them from drinking water installations Backflow prevention arrangement to prevent undesirable reversal flow of non-potable water into drinking water network (open outlet) must be installed GW reuse systems must be provided with an automatic backup system, to ensure continuous supply of service water. Drinking water, rainwater or other water source of suitable quality can be used Childrensearth.org Requirements for GW recycling & reuse

15. Operational Requirements Energy input for GWM system should not exceed that for conventional wastewater treatment system. (This should be less than 2 kWh for treatment including distribution of one cu. m of service water) Use of chemicals for treatment, operation and maintenance should be avoided Low operation and maintenance expenditure System should be robust, able to take fluctuations; system components should be long-lasting Skilled knowledge needed for planning, installation as well as maintenance of GWM systems. Involving planners at early planning phase contributes significantly to cost savings Childrensearth.org Requirements for GW recycling & reuse

16. Maintenance Requirements When high-load GW flows (from kitchen and washing machines) are also considered for treatment, maintenance expenditure is expected to be slightly higher than when only low-load GW is reused In general, automatic and periodic cleaning of sieves/filters would provide for a low-maintenance and trouble-free operation An internet-based control/monitoring unit helps optimise system operation and reduces costs for maintenance and operation Childrensearth.org Requirements for GW recycling & reuse

17. Reuse option affects the choice of the treatment technology Indoor reuse: urinal and toilet flushing, cleaning, laundry Outdoor reuse: watering lawns and domestic gardens, street cleaning, washing vehicles, cooling towers, irrigation of agricultural areas and groundwater recharge Childrensearth.org Options for reuse of GW

18. Technologies for GW treatment Childrensearth.org

19. Technologies for GW treatment Childrensearth.org

20. Technologies for GW treatment Cost factors Total costs for a GWM system are usually allocated to: System technology Use dual piping system Installation costs Operating costs (energy, personnel costs, monitoring) Maintenance and repair costs As a rule, depending on drinking water availability, water costs and GW recycling technology used, amortisation period of less then 10 years can be achieved Childrensearth.org

21. Reuse option affects the choice of the treatment technology Indoor reuse: urinal and toilet flushing, cleaning, laundry Outdoor reuse: watering lawns and domestic gardens, street cleaning, washing vehicles, cooling towers, irrigation of agricultural areas and groundwater recharge Childrensearth.org Options for reuse of GW

22. Grey Wastewater generated from bathing, washing, general cleaning, kitchen, maintenance of livestock, as well as from community stand posts, wells, hand pumps and other institutional areas, etc contains only one-tenth of the nitrogen that blackwater does and significantly fewer pathogens. As a result, the organic content of greywater decomposes more rapidly than that of blackwater and thus, its treatment is easier. Conveyance systems – closed drains, small bore pipe system Childrensearth.org

23. Grey Details of existing conveyance systems, if any Quality of the greywater generated Availability of land for development of GW treatment facilities Estimated amount of greywater generated Details of greywater reuse and recharge, if any Length of additonal conveyance lines required Location of the proposed treatment unit Treatment technology proposed Treatment capacity of the unit ( litres /day) Amount of greywater proposed to be treated per day ( litres ) Childrensearth.org

24. GWM O&M of Recycling solution Installation of screens into the drains coming out of the discharge points Regular cleaning and removal of inorganic /unwanted materials from drains Maintenance of cleanliness and hygienic condition on the premises Removal of grit, dirt, plastic, paper, etc. from the drains where the school drain is connected to the main sewage drain Routine cleaning of the fi lter beds Servicing and overhauling of all the electro-mechanical devices (pumps, motor, blowers, light fi ttings , control panel, etc.) as per the schedule Checking of all the civil structures for leakages, and adoption of corrective actions Raking of screens in the screening chamber and disposal of screenings in an environmentally responsible manner, Replacement/replenishing of bio-media/culture as required Painting of the interior and exterior of the units as per the schedule Routine testing of effl uent parameters like Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), pH, Total Suspended Solids (TSS), Total Nitrogen (T-N) and Total Phosphorus (T-P), etc. prior to discharge and adoption of corrective measures in case permissible values are exceeded Childrensearth.org

25. GWM O&M of Conveyance system Cleaning/de-siltation of all the drainage lines, chambers, manholes, etc. Carrying out of minor repairs of the drainage lines like replacing broken sections, leakages in the lines and chambers, manhole covers, etc. Adoption of corrective measures at locations where frequent blockages are observed, if applicable. (e.g., installation of a screen upstream of sections Checking of the connections from toilets (black water), if any Periodic checking of whether the house drains are connected to an inspection chamber with a screen prior to connection to the public drains Childrensearth.org

26. Why Greywater recycling in Schools Currently 100% of all GW generated in schools is just mixed with toilet water and discharged into sewage, untreated. Light Greywater generated; easier to recycle; Huge volumes generated daily; Reuse for watering plants, cleaning, playgrounds, toilet flush; Land available to build constructed wetlands; Awareness among children & teachers; Huge measurable economic, social & environmental impact; Reduced water and electricity bills – Payback within 5 years; Reduced demand on freshwater for non-potable purposes; contributes to achieving most UN SDG’s As per several studies in India & abroad, GW generation rate in schools averages around 7 Litres/person/day. A school with 2000 children generates 14000 Litres GW/day; (14000 * 220 school days/ yr = 3.08 million Litres greywater/ yr ) Childrensearth.org

27. Horizontal Flow Constructed Wetlands Preferred solution - Horizontal Flow sub-surface constructed wetland (HFSSCW) using natural filters man-made systems; greywater recycling achieved through natural processes involving soil, vegetation, & microbial communities built on soft ground by digging trench pit of suitable dimension based on volume to be recycled, quality of influent GW, intermittent or continuous flow etc . (about 2m*1m*0.5m to recycle 1000 litres/day) water fed sub-surface; all filtration occurs below ground level - no stagnation, foul smell or mosquito breeding risk . Filter layers made of natural filters like different sized gravel & sand, coconut coir, moringa cake, burnt brick pieces, clay etc, beautified using aquatic plants able to tolerate fluctuations in hydraulic and organic load easy to integrate aesthetically into built environments; adaptable to variety of organic grey water characteristics natural bacteria and plants used & gravity is also taken into account during planning process Long life span of 15 yrs to 25 yrs , low maintenance, high efficiency & effectiveness, sustainable and scalable, low-cost, low O&M Childrensearth.org

28. Horizontal Flow Sub-Surface CW Front cross sectional view of HFSSCW Childrensearth.org

29. Horizontal Flow Sub-Surface CW How HFSSCW will look on completion Childrensearth.org

30. School Greywater Action Plan Awareness campaigns and activities for recycling greywater in public places and public institutions GW Action Plan submitted to a dozen reputed schools in Delhi – Greywater audit - site inspection to assess volume of GW, discharge points, preferred site for building solution etc School specific GW action plan with details on filter design & build, capacity and costs. When implemented to full capacity, will save 37 million litres of freshwater/ yr from a dozen schools in Delhi, India Childrensearth.org

31. Why need exposure through NASDaily Encourage and spur action by bulk producers of GW to recycle and reuse GW, thereby mitigating global water crisis Increase visibility and awareness about GW recycling, its benefits and urgency Childrensearth.org