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 '''A Leach Fieldleach field, or drainage field, is a network of perforated pipes that are laid in underground gravel-filled trenches to dissipate the effluent froma from a water-based Collection and Storage/Treatment or (Semi-) Centralized Treatment technology.'''

Effluent Pre-settled effluent is fed into a piping system (distribution box which directs and several parallel channels) that distributes the flow into several parallel channelsthe subsurface soil for absorption and subsequent treatment. A small dosing or pressurized distribution system releases the pressurized effluent into the Leach Field on a timer (usually 3 may be installed to 4 times a day). This ensures ensure that the whole length of the Leach Field leach field is utilized and that aerobic conditions are allowed to recover between dosings. Such a dosing system releases the pressurized effluent into the leach field with a timer (usually 3 to 4 times a day). ===Design Considerations=== Each trench is 0.3 to 1.5m 5 m deep and 0.3 to 1m 1 m wide. The bottom of each trench is filled with about 15cm 15 cm of clean rock and a perforated distribution pipe is laid overtopon top. More rock covers is placed to cover the pipe so that it is completely surrounded. The A layer of geotextile fabric is placed on the rock is covered with a layer of geotextile fabric to prevent small particles from plugging the pipe. A final layer of sand and/or topsoil covers the fabric and fills the trench to the ground level. The pipe should be placed 15cm from at least 15 cm beneath the surface to prevent effluent from surfacing. The trenches should be dug no longer than 20m 20 m in length and at least 1 to 2m 2 m apart. To prevent contamination, a leach field should be located at least 30 m away from any drinking water source. A leach field should be laid out such thatit will not interfere with a future sewer connection. The collection technology which precedes the leach field (e.g., Septic Tank, S.9) should be equipped with a sewer connection so that if, or when, the leach field needs to be replaced, the changeover can be done with minimal disruption.

- Can be used for the combined treatment and disposal of blackwater and greywater. <br> effluent- Has a long lifespan of 20 or more years (depending on conditions). <br> - Low to moderate maintenance requirements if operating without mechanical equipment- Relatively low capital cost, costs; low operating cost. costs| con=- Requires expert design and construction. <br> - Requires a large area (on a per person basis). <br> - Not all parts and materials may be locally available locally. <br> - Requires a large area <br>- Pretreatment Primary treatment is required to prevent clogging. <br> - May negatively affect soil and groundwater properties.

===AdequacyAppropriateness=== Leach Fields fields require a large area and unsaturated soil with good absorptive capacity to effectively dissipate the effluent. To prevent contaminationDue to potential oversaturation of the soil, a Leach Field should be located 30m away from a drinking water supply. Leach leach fields are not appropriate for dense urban areas. They can be used in almost every temperature, although there may be problems with pooling effluent in areas where the ground freezes. Homeowners who have a Leach Field leach field must be aware of how it works and what of their maintenance responsibilities are. Trees and deep-rooted plants should be kept away from the Leach Field leach field as they can crack and disturb the tile bed.

===Health Aspects/Acceptance===Since the technology is underground and requires little attention, users will rarely come in contact with the effluent and, therefore, it has no health risk. The leach field must be kept as far away as possible (at least 30 m) from any potentialpotable water source to avoid contamination.

Since the ===Operation & Maintenance=== A leach field will become clogged over time, although this may take 20 or more years, if a well-maintained and well-functioning primary treatment technology is underground and it requires little attentionin place. Effectively, a leach field should require minimal maintenance; however, if the system stops working efficiently, users will rarely come in contact with the effluent pipes should be cleaned and/or removed and so it replaced. To maintain the leach field, there should pose be no health riskplants or trees on it. The Leach Field must There should also be kept as far away as possible from (>30m) any potential potable water sources to avoid contaminationno heavy traffic above it because this could crush the pipes or compact the soil.

* CritesMorel, RA. and TchobanoglousDiener, GS. (19982006). Greywater Management in Low and Middle-Income Countries. Review of Different Treatment Systems for Households or Neighbourhoods. Eawag (Department Sandec), Dübendorf, CH.:Available at: [http://bookswww.googlesandec.com/books/about/Small_and_decentralized_wastewater_managch sandec.html?id=yx9SAAAAMAAJ Small and Decentralized Wastewater Management Systemsch]. WCB and McGraw-Hill, New York, USA. pp 905–927.

* Polprasert, C. and Rajput, VSV. S. (1982). [http://docs.watsan.net/Scanned_PDF_Files/Class_Code_3_Sanitation/323.2-82SE-884.pdf Environmental Sanitation Reviews: Septic Tank and Septic Systems]. Environmental Sanitation Information Center, AIT, Bangkok, ThailandTH.

* [http://wwwU.epaS.gov USEPA] EPA (1980). [http://www.epa.gov/nrmrl/pubs/625180012Design Manual.html Design manual- on-site wastewater treatment Onsite Wastewater Treatment and disposal systemsDisposal Systems. EPA-625/1-80-012]. Office of Research and Development, Municipal U.S. Environmental Research LaboratoryProtection Agency, Cincinnati, OhioOH, US.:Available at: [http://www.epa.gov epa.gov]