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<!{|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]]|

Input1=Blackwater|Input2=GreywaterBrownwater|Input3=Greywater| Input4= |Input5=|Output1=Faecal SludgeEffluent |Output2=Effluent Sludge | Output3= | Output4= | Output5=

'''A Septic Tank <br>Liquid flows through the tank and heavy particles sink to the bottom, while scum (mostly oil and grease) floats to the top. Over time, the solids that settle to the bottom are degraded anaerobically. However, the rate of accumulation is a watertight chamber made faster than the rate of concretedecomposition, fibreglassand the accumulated sludge and scum must be periodically removed. The effluent of the septic tank must bedispersed by using a [[Soak Pit]] (D.7) or [[Leach Field]] (D.8), PVC or plastictransported to another treatment technology via a [[Solids-free Sewer| Solids-Free Sewer]] (C.5). Generally, for the storage removal of 50% of solids, 30 to 40% of BOD and treatment a 1-log removal of blackwater E. coli can be expected in a well-designed and greywater. Settling maintained septic tank, although efficiencies vary greatly depending on operation and anaerobic processes reduce solids maintenance and organics, but the treatment is only moderateclimatic conditions.'''

A Septic Tank should typically have at least two chambers. The first chamber tanks should be at least 50% of the total length and when there are only two chambers, it should be 2/3 of the total length. Most of the solids settle out in the first chamber. The baffle, or the separation between the chambers, is to prevent scum and solids from escaping with the effluent. A T-shaped outlet pipe will further reduce the scum and solids that are discharged. Liquid flows into the tank and heavy particles sink to the bottom, while scum (oil and fat) floats to the top. With time, the solids that settle to the bottom are degraded anaerobically. However, the rate of accumulation is faster than the rate vented for controlled release of decomposition, odorous and the accumulated sludge must be removed at some point. Generally, Septic Tanks should be emptied every 2 to 5 years, although they should be checked yearly to ensure proper functioningpotentially harmful gases. The design of a Septic Tank septic tank depends on the number of users, the amount of water used per capita, the average annual temperature, the pumping desludging frequency and the characteristics of the wastewater. The retention time should be designed for 48 hours to achieve moderate treatment. A variation of the Septic Tank is called an aquaprivy, which is a simple storage and settling tank located directly below the toilet, so that the excreta fall into the tank. To prevent odours from surfacing, a waterseal must be maintained but it may not completely prevent smells and the tank must be frequently desludged. The effluent must be dispersed by using a [[Soak Pit]] or [[Leach Field]] or by transporting the effluent to another treatment technology via a [[Simplified Sewers]] or [[Solids-free Sewer|Solids-Free]]. 

- 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== 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 can be installed in every type of climate although the efficiency will be affected 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 are appropriate for rocky or flood-prone areas where pits or other technologies would not be appropriate. However, because they require frequent emptying and constant maintenance, they are only recommended for very specific applications. ==Health Aspects/Acceptance==  Although the removal of pathogens is not high, the entire tank is below the surface so users do not come in contact with any of the wastewater. Users should be careful when opening the tank because noxious and flammable gases may be released. Septic Tanks should have a vent. A vacuum truck should be used to empty the sludge from the Septic Tank. Users should not attempt to empty the pit themselves except with a manual technology like the [[Human-Powered Emptying and Transport|Gulper]]. ==Upgrading==

A Septic Tank that is connected to a [[Leach Field]] or a [[Soak Pit]] tanks can later be connected to a [[Solids-free Sewer]] if/when one is installedin every type of climate, although the efficiency will be lower in colder climates. They are not efficient at removing nutrients and pathogens.

==Maintenance=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.

Septic Tanks ===Operation & Maintenance=== Because of the delicate ecology, care should be checked taken not to ensure that they are watertight and discharge harsh chemicals into the levels of the scum septic tank. Scum and sludge should levels need to be monitored to ensure that the tank is functioning well. Because of the delicate ecologyGenerally, care septic tanks should be taken not emptied every 2 to discharge harsh chemicals into the 5 years. This is best done by using a [[Motorized Emptying and Transport | Motorized Emptying and Transport]] technology (C.3), but [[Human-Powered Emptying and Transport | Human-Powered Emptying]] (C.2) can also be an option. Septic Tank. The sludge tanks should be removed annually using a vacuum truck checked from time to time to ensure proper functioning of the Septic Tankthat they are watertight.

==References=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.

===References===* Elizabeth Tilley etCrites, R. and Tchobanoglous, G.al (20081998). [http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_high.pdf Compendium of Sanitation Small and Decentralized Wastewater Management Systems and Technologies] ([http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_low.pdf low res version]Book). Department of Water and Sanitation in Development Countries ([http://www.sandec.chWCB/ Sandec]) at the Swiss Federal Institute of Aquatic Science and Technology (Eawag)McGraw- Hill, New York, US. (Provides a full overview of sanitation systems.)

* Mara, DD. Oxfam (19962008). Low[https://oxfamilibrary.openrepository.com/bitstream/handle/10546/126711/tbn9-septic-tank-guidelines-Cost Urban Sanitation030608-en. Wileypdf?sequence=5&isAllowed=y Septic Tank Guidelines. Technical Brief]. Oxfam GB, ChichesterOxford, UK. (Sizing, volume and emptying calculations and example design solutions, Chapter 6.)

* Polprasert, C. and Rajput, VSV. 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, AIT, ThailandTH. pp 68–74. (Comprehensive design manual)68-74.

* Ulrich, A. (Ed.), Reuter, S. (Ed.), Gutterer, B. (Ed.), Sasse, L., Panzerbieter, T. and Reckerzügel, T. (19982009). DEWATS[https://wedc-knowledge.lboro.ac.uk/resources/books/DEWATS_-_Chapter_01. pdf Decentralised Wastewater Treatment Systems (DEWATS) and Sanitation in Developing Countries. BORDAA Practical Guide]. WEDC, Bremen Overseas Research and Development AssociationLoughborough University, BremenLeicestershire, GermanyUK. (Excel® Spreadsheet codes for sizing septic tanks.) General Information: