<!{|style="float: left;"|{{Language-- table at top of page with logo, picture, Application level, Management level, and input-output tables -->box|english_link=Septic_Tank|french_link=Fosse_Septique|spanish_link=Fosa_Septica|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 }}|}{|width="100%"|style="width:50%;"|{{santablesantable_new|sys1=[[Blackwater Treatment System with Infiltration|56]]|sys2=[[Blackwater Treatment System with SewerageEffluent Transport|67]]|
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Input1=Blackwater|Input2=GreywaterBrownwater|Input3=Greywater| Input4= |Input5=|Output1=Faecal SludgeEffluent |Output2=Effluent Sludge | Output3= | Output4= | Output5=|english_link=Septic_Tank|french_link=Fosse_Septique
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[[Image:Icon_septic_tank.png |right|95px80px]][[Image:Aqua_privyss.PNG|thumb|right|200px|[[Aqua privy |Aqua privy]]]]'''A Septic Tank septic tank is a watertight chamber made of concrete, fibreglass, PVC or plastic, for the storage and treatment of through which blackwater and greywaterflows for primary treatment. Settling and anaerobic processes reduce solids and organics, but the treatment is only moderate.'''
A Septic Tank should typically have at least two chambers. The first chamber should be at least 50% of <br>Liquid flows through the total length tank and when there are only two chambersheavy particles sink to the bottom, it should be 2/3 of while scum (mostly oil and grease) floats to the total lengthtop. Most of Over time, the solids that settle out in to the first chamberbottom are degraded anaerobically. The baffleHowever, or the separation between rate of accumulation is faster than the chambersrate of decomposition, is to prevent scum and solids from escaping with the accumulated sludge and scum must be periodically removed. The effluentof the septic tank must bedispersed by using a [[Soak Pit]] (D. A T7) or [[Leach Field]] (D.8), or transported to another treatment technology via a [[Solids-free Sewer| Solids-shaped outlet pipe will further reduce Free Sewer]] (C.5). Generally, the scum removal of 50% of solids, 30 to 40% of BOD and a 1-log removal of E. coli can be expected in a well-designed and maintained septic tank, although efficiencies vary greatly depending on operation and maintenance and solids that are dischargedclimatic conditions.
Liquid flows into the ===Design Considerations=== A septic tank and heavy particles sink to the bottom, while scum (oil and fat) floats to the topshould have at least two chambers. With time, the solids that settle to the bottom are degraded anaerobically. However, the rate The first chamber should be at least 50% of accumulation is faster than the rate of decompositiontotal length, and the accumulated sludge must be removed at some point. Generally, Septic Tanks should be emptied every 2 to 5 yearswhen there are only two chambers, although they it should be checked yearly to ensure proper functioning. The design two thirds of a Septic Tank depends on the number total length. Most of users, the amount of water used per capita, the average annual temperature, the pumping frequency and the characteristics of solids settle out in the wastewaterfirst chamber. The retention time should be designed for 48 hours to achieve moderate treatment. ==Aqua privy== [[Image:Aqua_privyss.PNG|thumb|right|150px|[[Aqua privy |Aqua privy]]]] A variation of the Septic Tank is called an aqua privybaffle, which is a simple storage and settling tank located directly below the toilet, so that the excreta fall into the tank. A housing or shed is built over the tank. A vent pipe with a fly screen at separation between the top end chambers, is attached to the housing. To prevent odours scum and solids from surfacing, a water seal must be maintained by adding sufficient water per toilet visit to escaping with the tank via the dropeffluent. A T-shaped outlet pipe to replace any losses. However, this may not completely prevent smells further reduces the scum and the tank must be frequently desludgedsolids that are discharged. The effluent must be dispersed by using a [[Soak Pit]] or [[Leach Field]] or by transporting the effluent Accessibility to another treatment technology via a [[Simplified Sewers]] or [[Solids-free Sewer|Solids-Free]]all chambers (through access ports) is necessary for maintenance.
Septic tanks should be vented for controlled release of odorous and potentially harmful gases. The design of a septic tank depends on the number of users, the amount of water used per capita, the average annual temperature, the desludging frequency and the characteristics of the wastewater. The retention time should be 48 hours to achieve moderate treatment.
A variation of the septic tank is called an [[Aqua privy | Aquaprivy]]. This is a simple storage and settling tank that is located directly below the toilet so that the excreta fall into it. The Aquaprivy has a low treatment efficiency.
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{{procontable | pro=
- Can be built Simple and repaired with locally available materials. <br> - Long service life. robust technology<br> - No real problems with flies or odours if used correctly. electrical energy is required<br> - Low capital costs, moderate operating costs depending on water and emptying. <br> - Small land area required. Long service life<br> - No electrical energy Small land area required. (can be built underground)| con=- Low reduction in pathogens, solids and organics. <br> - Regular desludging must be ensured<br>- Effluent and sludge require secondary further treatment and/or appropriate discharge. <br> - Requires constant source of water.
}}
==Adequacy=Appropriateness=== This technology is most commonly applied at the household level. Larger, multi-chamber septic tanks can be designed for groups of houses and/ or public buildings (e.g., schools). A septic tank is appropriate where there is a way of dispersing or transporting the effluent. If septic tanks are used in densely populated areas, onsite infiltration should not be used, otherwise, the ground will become oversaturated and contaminated, and wastewater may rise up to the surface, posing a serious health risk. Instead, the septic tanks should be connected to some type of Conveyance technology, through which the effluent is transported to a subsequent Treatment or Disposal site.
A Septic Tank Even though septic tanks are watertight, it is appropriate not recommended to construct them in areas with high groundwater tables or where there is a way of dispersing or transporting the effluentfrequent flooding. Because the Septic Tank septic tank must be desludged regularlyde-sludged, a vacuum truck should be able to access the location. Often Septic Tanks , septic tanks are installed in the home, under the kitchen or bathroom , which makes emptying difficult. If Septic Tanks are used in densely populated areas, on-site infiltration should not be used otherwise the ground will become oversaturated and excreta may rise up to the surface posing a serious health risk. Instead, the Septic Tank should be connected to a sewer and the effluent should be transported to a subsequent treatment or disposal site. Larger, multi-chamber Septic Tanks can be designed for groups of houses and/or public buildings (i.e. schools). Generally, the removal of 50% of solids, 30 to 40 % of biochemical oxygen demand (BOD) and a 1-log removal of E.coli can be expected in a well designed Septic Tank although efficiencies vary greatly depending on operation and maintenance and climactic conditions.
Septic Tanks tanks can be installed in every type of climate , although the efficiency will be affected lower in colder climates. Even though the Septic Tank is watertight, it should not be constructed in areas with high groundwater tables or where there is frequent flooding. Aquaprivies can be built indoors and above ground and They are appropriate for rocky or flood-prone areas where pits or other technologies would not be appropriate. However, because they require frequent emptying efficient at removing nutrients and constant maintenance, they are only recommended for very specific applicationspathogens.
===Health Aspects/Acceptance== = Under normal operating conditions, users do not come in contact with the influent or effluent. Effluent, scum and sludge must behandled with care as they contain high levels of pathogenic organisms. Users should be careful when opening the tank becausenoxious and flammable gases may be released.
Although ===Operation & Maintenance=== Because of the removal of pathogens is delicate ecology, care should be taken not high, to discharge harsh chemicals into the entire septic tank is below the surface so users do not come in contact with any of the wastewater. Users should Scum and sludge levels need to be careful when opening monitored to ensure that the tank because noxious and flammable gases may be releasedis functioning well. Septic Tanks should have a vent. A vacuum truck Generally, septic tanks should be used emptied every 2 to empty the sludge from the Septic Tank5 years. Users should not attempt to empty the pit themselves except with This is best done by using a manual [[Motorized Emptying and Transport | Motorized Emptying and Transport]] technology like the (C.3), but [[Human-Powered Emptying and Transport|GulperHuman-Powered Emptying]](C.2) can also be an option. Septic tanks should be checked from time to time to ensure that they are watertight.
==Upgrading=Field experiences===<br>{|style="border: 2px solid #e0e0e0; width: 40%; text-align: justify; background-color: #e9f5fd;" cellpadding="2"<!--rsr logo here-->|- style="vertical-align: top"|[[Image:akvorsr logo_lite.png|center|60px|link=http://akvo.org/products/rsr/]]<!--project blocks here-->|- style="vertical-align: bottom"|[[Image:rsr 727.jpg |thumb|center|140px|<font size="2"><center>[http://rsr.akvo.org/project/727/ RSR Project 727]<br>TESO North School and Community WASH Project</center></font>|link=http://rsr.akvo.org/project/727/ ]] |[[Image:project 195.png |thumb|center|140px|<font size="2"><center>[http://rsr.akvo.org/project/195/ RSR Project 195]<br>Basic Sanitation <br>for Loja Province</center></font>|link=http://rsr.akvo.org/project/195/ ]] |}
A Septic Tank that is connected to a [[Leach Field]] or a [[Soak Pit]] can later be connected to a [[Solids-free Sewer]] if/when one is installed.<br>
==Maintenance=Manuals, videos, and links===This [http://wiki.watermissions.org/(X(1)S(x3fkdoq5xqskutjl4j4gkmid))/GetFile.aspx?Page=Simple%20Excreta%20and%20Washwater%20Disposal%20SAN1&File=san1d4.pdf document] lists the specifications that need to be met for a succesful Aqua Privy.
Septic Tanks should be checked to ensure that they are watertight ===References===* Crites, R. and the levels of the scum Tchobanoglous, G. (1998). Small and sludge should be monitored to ensure that the tank is functioning wellDecentralized Wastewater Management Systems (Book). Because of the delicate ecologyWCB/McGraw- Hill, care should be taken not to discharge harsh chemicals into the Septic Tank. The sludge should be removed annually using a vacuum truck to ensure proper functioning of the Septic TankNew York, US.
==Manuals==This [http://www* Mara, D. D.lifewater(1996).org/resources/san1/san1d4Low-Cost Urban Sanitation (Book).pdf document] lists the specifications that need to be met for a succesful Aqua PrivyWiley, Chichester, UK.(Sizing, volume and emptying calculations and exampledesign solutions – Chapter 6)
* Oxfam (2008). [https://oxfamilibrary.openrepository.com/bitstream/handle/10546/126711/tbn9-septic-tank-guidelines-030608-en.pdf?sequence=5&isAllowed=Acknowledgements=={{:Acknowledgements Sanitation}}y Septic Tank Guidelines. Technical Brief]. Oxfam GB, Oxford, UK.
==References * Polprasert, C. and external links==Rajput, V. S. (1982). [https://www.susana.org/_resources/documents/default/3-2995-7-1519811046.pdf Environmental Sanitation Reviews. Septic Tank and Septic Systems]. Environmental Sanitation Information Center, AIT, Bangkok, TH. pp. 68-74.
Detailed Design Information:*MaraUlrich, DDA. (1996Ed.), Reuter, S. Low-Cost Urban Sanitation(Ed. Wiley), ChichesterGutterer, UKB. (SizingEd.), volume Sasse, L., Panzerbieter, T. and emptying calculations Reckerzügel, T. (2009). [https://wedc-knowledge.lboro.ac.uk/resources/books/DEWATS_-_Chapter_01.pdf Decentralised Wastewater Treatment Systems (DEWATS) and example design solutionsSanitation in Developing Countries. A Practical Guide]. WEDC, Chapter 6Loughborough University, Leicestershire, UK.)
* Polprasert, C. and Rajput, VS. (1982). Environmental Sanitation Reviews===Acknowledgements==={{: Septic Tank and Septic Systems. Environmental Acknowledgements Sanitation Information Center, Bangkok, AIT, Thailand. pp 68–74. (Comprehensive design manual) * Sasse, L. (1998). DEWATS. Decentralised Wastewater Treatment in Developing Countries. BORDA, Bremen Overseas Research and Development Association, Bremen, Germany. (Excel® Spreadsheet codes for sizing septic tanks.) General Information: * Crites, R. and Tchobanoglous, G. (1998). Small and Decentralized Wastewater Management Systems. WCB and McGraw-Hill, New York, USA.}}