Changes

<!{|style="float: left;"|{{Language-- table at top of page with logo, picture, Application level, Management level, and input-output tables -->box|english_link=Anaerobic_Filter|french_link=Filtre_Anaérobie|spanish_link=Filtro_Anaerobico|hindi_link=coming soon|malayalam_link=coming soon|tamil_link=coming soon | korean_link=coming soon chinese_link=Coming soon | indonesian_link=Coming soon | japanese_link=Coming soon }}|}

sys1=[[Blackwater Treatment System with Infiltration|56]]|sys2=[[Blackwater Treatment System with SewerageEffluent Transport|67]]|

ApplHousehold=XXX|

ManHousehold=XXX|

Input1=Blackwater|Input2=GreywaterBrownwater|Input3=Greywater| Input4= |Input5=|Output1=Faecal SludgeEffluent|Output2=Effluent Sludge | Output3= | Output4= | Output5=|english_link=Anaerobic_Filter|french_link=Filtre_Anaérobie|spanish_link=Filtro_Anaerobico

|[[Image:Anaerobic_filter.png |right|300px500px]]

[[Image:Icon_anaerobic_filter.png |right|80px]]'''An anaerobic filter is a fixed----bed biological reactor with one or more filtration chambers in series. As wastewater flows through the filter, particles are trapped and organic matter is degraded by the active biomass that is attached to the surface of the filter material.'''

[[Image:Icon_anaerobic_filter.png |right|95px]]<br>'''An Anaerobic Filter is a fixed-bed biological reactor. As wastewater flows through the filterWith this technology, particles are trapped suspended solids and organic matter BOD removal can be as high as 90%, but is degraded by the biomass that typically between 50% and 80%. Nitrogen removal is attached to the filter materiallimited and normally does not exceed 15% in terms of total nitrogen (TN).'''

This technology consists ===Design Considerations=== Pre- and primary treatment is essential to remove solids and garbage that may clog the filter. The majority of settleable solids are removed in a sedimentation tank chamber in front of the anaerobic filter. Small-scale, stand-alone units typically have an integrated settling compartment, but primary sedimentation can also take place in a separate [[Settler]] (T.1) or another preceding technology (e.g., existing [[Septic Tank]]s) followed by one or more filter chambers. Filter material commonly used includes gravel, crushed rocks, cinder, or specially formed plastic pieces. Typical filter material sizes range from 12 to 55mm Designs without a settling compartment (as shown in diameterT. Ideally, the material will provide between 90 to 300m2 of surface area per 1m3 4) are of reactor volume. By providing a large surface area particular interest for (Semi-) Centralized Treatment plants that combine the bacterial massanaerobic filter with other technologies, there is increased contact between such as the organic matter and the active biomass that effectively degrades it[[Anaerobic Baffled Reactor (ABR)| Anaerobic Baffled Reactor (ABR)]] (ABR, T.3).

The Anaerobic Filter can be filters are usually operated in either upflow or downflow mode. The upflow mode is recommended because there is less risk that the fixed biomass will be washed out. The water level should cover the filter media by at least 0.3m 3 m to guarantee an even flow regime. The hydraulic retention time (HRT) is the most important design parameter influencing filter performance. An HRT of 12 to 36 hours is recommended. The ideal filter should have a large surface area for bacteria to grow, with pores large enough to prevent clogging. The surface area ensures increased contact between the organic matter and the attached biomass that effectively degrades it. Ideally, the material should provide between 90 to 300 m2 of surface area per m3 of occupied reactor volume. Typical filter material sizes range from 12 to 55 mm in diameter. Materials commonly used include gravel, crushed rocks or bricks, cinder, pumice, or specially formed plastic pieces, depending on local availability.

Studies have shown that The connection between the HRT is the most important design parameter influencing filter performance. An HRT of 0chambers can be designed either with vertical pipes or baffles.5 Accessibility to 1.5 days is a typical and recommended. A maximum surface-loading all chambers (i.e. flow per areathrough access ports) rate of 2is necessary for maintenance.8m/d has proven to The tank should be suitable. Suspended solids and BOD removal can be as high as 85% vented to 90% but is typically between 50% and 80%. Nitrogen removal is limited allow for controlled release of odorous and normally does not exceed 15% in terms of total nitrogen (TN)potentially harmful gases.

- Resistant to organic and hydraulic shock loads. <br> - No electrical energy is required. <br> - Can be built and repaired with locally available materials. Low operating costs <br> - Long service life. <br> - High reduction of BOD and solids <br>- Low sludge production; the sludge is stabilized <br>- Moderate capital costs, moderate operating costs depending on emptying; area requirement (can be lowered depending on number of users. built underground) <br> - High reduction of BOD and solids. | con=- Requires constant source expert design and construction <br>- Low reduction of water. pathogens and nutrients <br> - Effluent and sludge require secondary further treatment and/or appropriate discharge. <br> - Low reduction Risk of pathogens clogging, depending on pre- and nutrients. primary treatment <br> - Requires expert design Removing and construction. <br> - Long start up time.cleaning the clogged filter media is cumbersome

==Adequacy=Appropriateness=== This technology is easily adaptable and can be applied at the household level or a , in small neighbourhood (refer to Technology Information Sheet T2: Anaerobic Filter for information about applying an Anaerobic Filter at the community level). An Anaerobic Filter can be designed for a single house neighbourhoods or a group of houses that are using a lot of water for clothes washing, showering, and toilet flushingeven in bigger catchment areas. It is only most appropriate if water use is high, ensuring that the supply where a relatively constant amount of wastewater blackwater and greywater is constantgenerated. The Anaerobic Filter will not operate at full capacity for six to nine months after installation because of the long start up time required for the anaerobic biomass to stabilize. Therefore, the Anaerobic Filter technology should not filter can be used when for secondary treatment, to reduce the need organic loading rate for a subsequent aerobic treatment technology is immediate. Once working at full capacity it is a stable technology that requires little attention. The Anaerobic Filter should be watertight but it should still not be constructed in areas with high groundwater tables or where there is frequent flooding. Depending on land availability and the hydraulic gradient of the sewer (if applicable)step, the Anaerobic Filter can be built above or below groundfor polishing. It can be installed in every type of climate, although the efficiency will be affected in colder climates. ==Health Aspects/Acceptance== Because the Anaerobic Filter unit is underground, users do not come in contact with the influent or effluent. Infectious organisms are not sufficiently removed, so the effluent should be further treated or discharged properly. The effluent, despite treatment, will still have a strong odour and care should be taken to design and locate the facility such that odours do not bother community members. To prevent the release of potentially harmful gases, the Anaerobic Filters should be vented. The desludging of the filter is hazardous and appropriate safety precautions should be taken. ==Maintenance==

Active bacteria must This technology is suitable for areas where land may be added to start up limited since the Anaerobic Filter. The active bacteria can come from sludge from a septic tank that has been sprayed onto the filter material. The flow should be gradually increased over time, is most commonly installed underground and the filter should be working at maximum capacity within six to nine monthsrequires a small area. With time, the solids will clog the pores of the filter. As well, the growing bacterial mass will become too thick and will break off and clog pores. A sedimentation tank before the filter Accessibility by vacuum truck is required to prevent the majority of settleable solids from entering the unitimportant for desludging. Some clogging increases the ability Anaerobic filters can be installed in every type of the filter to retain solids. When climate, although the efficiency of the filter decreases, it must be cleanedis lower in colder climates. Running the system in reverse mode to dislodge accumulated biomass They are not efficient at removing nutrients and particles cleans the filterspathogens. Alternatively, Depending on the filter material can , however, complete removal of worm eggs may be removed and cleanedachieved. The effluent usually requires further treatment.

==References=Health Aspects/Acceptance=== Under normal operating conditions, users do not come in contact with the influent or effluent. Effluent, scum and sludge must be handled with care as they contain high levels of pathogenic organisms. The effluent contains odorous compounds that may have to be removed in a further polishing step. Care should be taken to design and locate the facility such that odours do not bother communitymembers.

* Morel===Operation & Maintenance=== An anaerobic filter requires a start-up period of 6 to 9 months to reach full treatment capacity since the slow growing anaerobic biomass first needs to be established on the filter media. To reduce startup time, A. and Dienerthe filter can be inoculated with anaerobic bacteria, Se. (2006)g. [http://www.eawag, by spraying Septic Tank sludge onto the filter material.ch/forschung/sandec/publikationen/ewm/dl/GW_managementThe flow should be gradually increased over time.pdf Greywater Management in Low and Middle-Income Countries, Review of different treatment systems for households or neighbourhoods]. Swiss Federal Institute Because of Aquatic Science and Technology (Eawag), Dübendorf, Switzerland. Short summary including case studiesthe delicate ecology, page 28care should be taken not to discharge harsh chemicals into the anaerobic filter.

* PolprasertScum and sludge levels need to be monitored to ensure that the tank is functioning well. Over time, Csolids will clog the pores of the filter. As well, the growing bacterial mass will become too thick, break off and Rajputeventually clog pores. When the efficiency decreases, VSthe filter must be cleaned. This is done by running the system in reverse mode (1982backwashing). [http://docs.watsan.net/Scanned_PDF_Files/Class_Code_3_Sanitation/323.2-82SE-884.pdf Environmental Sanitation Reviews: Septic Tank or by removing and Septic Systems]. Environmental Sanitation Information Center, AIT, Bangkok, Thailandcleaning the filter material. pp 68–74Anaerobic filter tanks should be checked from time to time to ensure that they are watertight.

===References===* SasseMorel, LA. and Diener, S. (19982006). [httphttps://www.indiawaterportalsusana.org/sites_resources/indiawaterportal.orgdocuments/filesdefault/Decentralised_%20wastewater_%20treatment_%20in_%20developing_%20countries_A_%20handbook_%20by_%20BORDA_19982-947-en-greywater-management-2006.pdf DEWATS: Decentralised Wastewater Treatment Greywater Management in Developing Low and Middle-Income Countries]. BORDAReview of Different Treatment Systems for Households or Neighbourhoods. Eawag (Department Sandec), Bremen Overseas Research and Development AssociationDübendorf, Bremen, Germany. Design summary including Excel-based design programCH.

* von SperlinSperling, M. and de Lemos Chernicharo, CAC. A. (2005). [httphttps://www.iwapublishing.com/pdfsites/default/files/contentsebooks/isbn1843390027_contents9781780402734.pdf Biological Wastewater Treatment in Warm Climate Regions]. , Volume One]. IWAPublishing, London, UK. pp 728–804. Detailed design instructions728-804.

* VigneswaranUlrich, A. (Ed.), Reuter, S.(Ed.), Gutterer, B. (Ed.), et alSasse, L., Panzerbieter, T. and Reckerzügel, T. (19862009). [httphttps://bookswedc-knowledge.lboro.googleac.comuk/resources/books/about/Anaerobic_Wastewater_TreatmentDEWATS_-_Chapter_01.html?id=NIJJcgAACAAJ Environmental Sanitation Reviews: Anaerobic pdf Decentralised Wastewater Treatment-Attached growth Systems (DEWATS) and Sludge blanket processSanitation in Developing Countries. A Practical Guide]. Environmental Sanitation Information CenterWEDC, Loughborough University, AIT BangkokLeicestershire, ThailandUK. (Design criteria and diagrams in Chapter 2.summary including Excel spreadsheets for design calculations)

===Acknowledgements===