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sys1=[[Single Pit System |1]]|
sys2=[[Blackwater Treatment System with Infiltration|56]]|sys3=[[Blackwater Treatment System with SewerageEffluent Transport|67]]|sys4=[[Blackwater Transport to (Semi-) Centralized Treatment System |78]]|sys5=[[Sewerage System with Urine Diversion|89]]|
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Input1=Blackwater|Input2=Greywater |Input3= Brownwater | Input4= Sludge |Input5=|Output1= Faecal Sludge | Output2=Effluent | Output3= | Output4= | Output5=|english_link=Waste_Stabilization_Pond|french_link=Bassins_de_lagunage|spanish_link=Estanques_de_Estabilizacion_de_Desperdicios
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'''Waste Stabilization Ponds (WSPs) are large, manmade water bodies. The ponds are filled with wastewater that is then treated by naturally occurring processes. The ponds can be used individually, or linked in a series for improved treatment. There are three types of ponds, (1) anaerobic, (2) facultative and (3) aerobic (maturation), each with different treatment and design characteristics.'''
For the most effective treatment, WSPs should be linked in a series of three of more with effluent being transferred from the anaerobic pond to the facultative pond and finally the aerobic pond. The anaerobic pond reduces solids and BOD as a pre<br>-treatment stage. The pond is a fairly deep man-made lake where the entire depth of the pond is anaerobic. Anaerobic ponds are built to a depth of 2 to 5m and have a relatively short detention time of 1 to 7 days. The actual design will depend on the wastewater characteristics and the loading; a comprehensive design manual should be consulted for all types of WSPs. Anaerobic bacteria convert organic carbon into methane and in the process, remove up to 60% of the BOD. Anaerobic ponds are capable of treating strong wastewaters.--<br>
In a series of [[Image:Icon_waste_stabilization_ponds.png |right|80px]]'''Waste Stabilization Ponds (WSPs the effluent from the anaerobic pond is transferred to the facultative pond) are large, where further BOD is removed. A facultative pond is shallower than an anaerobic pond and both aerobic and anaerobic processes occur within the pondman-made water bodies. The top layer of the pond receives oxygen from natural diffusionponds can be used individually, wind mixing and algaedriven photosynthesis. The lower layer is deprived of oxygen and becomes anoxic or anaerobiclinked in a series for improved treatment. Settleable solids accumulate and There are digested on the bottom three types of the pond. The aerobic and ponds, (1) anaerobic organisms work together to achieve BOD reductions of up to 75%. The pond should be constructed to a depth of 1 to , (2.5m ) facultative and (3) aerobic (maturation), each with different treatment and have a detention time between 5 to 30 daysdesign characteristics.'''
Following <br>For the anaerobic and the facultative ponds can most effective treatment, WSPs should be any number linked in a series of aerobic (maturation) ponds to achieve a highly polished three or more with effluent. An aerobic flowing from the anaerobic pond is commonly referred to as a maturationthe facultative pond and, polishingfinally, or finishing to the aerobic pond. The anaerobic pond because it is usually the last step primary treatment stage and reduces the organic load in a series of ponds and provides the final level of treatmentwastewater. It is the shallowest The entire depth of the ponds, usually constructed to a depth between 0.5 to 1.5m this fairly deep to ensure that the sunlight penetrates the full depth for photosynthesis. Because photosynthesis pond is driven by sunlight, the dissolved oxygen levels are highest during the day and drop off at nightanaerobic. Whereas anaerobic Solids and facultative ponds are designed for BOD removal, maturation ponds are designed for pathogen removal. Dissolved oxygen in the lake is provided occurs by natural wind mixing sedimentation and by photosynthetic algae that release oxygen into through subsequent anaerobic digestion inside the watersludge. If used in combination with algae Anaerobic bacteria convert organic carbon into methane and/or fish harvesting, through this type process, remove up to 60% of pond is effective at removing the majority of nitrogen and phosphorus from the effluentBOD.
To prevent leachingIn a series of WSPs, the effluent from the anaerobic pond is transferred to the facultative pond, wherefurther BOD is removed. The top layer of the ponds should have a linerpond receives oxygen from natural diffusion, wind mixing and algae-driven photosynthesis. The lower layer is deprived of oxygen and becomes anoxic or anaerobic. Settleable solids accumulate and are digested on the bottom of the pond. The liner can be clayaerobic and anaerobic organisms work together to achieve BOD reductions of up to 75%. Anaerobic and facultative ponds are designed for BOD removal, asphaltwhile aerobic ponds are designed for pathogen removal. An aerobic pond is commonly referred to as a maturation, compacted earthpolishing, or another impervious materialfinishing pond because it is usually the last step in a series of ponds and provides the final level of treatment. To protect It is the pond from runoff shallowest of the ponds, ensuring that sunlight penetrates the full depth for photosynthesis to occur. Photosynthetic algae release oxygen into the water and erosionat the same time consume carbon dioxide produced by the respiration ofbacteria. Because photosynthesis is driven by sunlight, a protective berm should be constructed around the pond using dissolved oxygen levels are highest during the excavated materialday and drop off at night. Dissolved oxygen is also provided by natural wind mixing.
===Design Considerations===
Anaerobic ponds are built to a depth of 2 to 5 m and have a relatively short detention time of 1 to 7 days. Facultative ponds should be constructed to a depth of 1 to 2.5 m and have a detention time between 5 to 30 days. Aerobic ponds are usually between 0.5 to 1.5 m deep. If used in combination with [[Aquaculture Ponds | algae and/or fish harvesting]] (see D.9), this type of pond is effective at removing the majority of nitrogen and phosphorus from the effluent. Ideally, several aerobic ponds can be built in series to provide a high level of pathogen removal.
[[Pre-Treatment Technologies|Pre-Treatment]] (see PRE, p. 100) is essential to prevent scum formation and to hinder excess solids and garbage from entering the ponds. To prevent leaching into the groundwater, the ponds should have a liner. The liner can be made from clay, asphalt, compacted earth, or any other impervious material. To protect the pond from runoff and erosion, a protective berm should be constructed around the pond using the excavated material. A fence should be installed to ensure that people and animals stay out of the area and that garbage does not enter the ponds.
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{{procontable | pro=
- High reduction in pathogens. Resistant to organic and hydraulic shock loads <br> - Can be built High reduction of solids, BOD and repaired with locally available materials. pathogens <br> - Construction can provide short-term employment to local labourers. High nutrient removal if combined with aquaculture <br> - Low operating cost. costs <br> - No electrical energy is required. <br> - No real problems with flies insects or odours if designed and maintained correctly. | con=- Requires expert design and supervision. a large land area <br> - Variable High capital cost costs depending on the price of land. <br> - Requires large land area. expert design and construction <br> - Effluent/sludge require secondary Sludge requires proper removal and treatment and/or appropriate discharge.
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==Adequacy=Appropriateness=== WSPs are among the most common and efficient methods of wastewater treatment around the world. They are especially appropriate for rural and peri-urban communities that have large, open unused landsland, away ata distance from homes and public spaces. They are not appropriate for very dense or urban areas. WSPs work in most climates, but are most efficient in warm, sunny climates. In the case of cold climates, the retention times and loading rates can be adjusted so that efficient treatment can be achieved. ==Health Aspects/Acceptance==
===Health Aspects/Acceptance===
Although effluent from aerobic ponds is generally low in pathogens, the ponds should in no way be used for recreation or as a direct source of water for consumption or domestic use.
==Upgrading=Operation & Maintenance=== Scum that builds up on the pond surface should be regularly removed. Aquatic plants (macrophytes) that are present in the pond should also be removed as they may provide a breeding habitat for mosquitoes and prevent light from penetrating the water column. The anaerobic pond must be desludged approximately once every 2 to 5 years, when the accumulated solids reach one third of the pond volume. For facultative ponds sludge removal is even rarer and maturation ponds hardly ever need desludging. Sludge can be removed by using a raft-mounted sludge pump, a mechanical scraper at the bottom of the pond or by draining and dewatering the pond and removing the sludge with a front-end loader.
===Upgrading===
Ideally, several aerobic ponds can be built in series to provide a high level of pathogen removal. A final aquaculture pond can be used to generate income and supply a locally grown food source.
==Maintenance=References===
To prevent scum formation* Kayombo, excess solids and garbage from entering the pondsS., Mbwette, pre-treatment (with grease traps) is essential to maintain the pondsT. The pond must be desludged once every 10 to 20 yearsS. A fence should be installed to ensure that people ., Katima, J. H. Y., Ladegaard, N. and animals stay out of the area and excess garbage does not enter the pondsJorgensen, S. E. Rodents may invade the berm and cause damage to the liner(2004). Raising the water level should prompt rodents to evacuate the berm[https://sswm. Care should be taken to ensure that plant material does not fall into the pondsinfo/sites/default/files/reference_attachments/KAYOMBO%20et%20al%202004%20Waste%20Stabilization%20Ponds%20and%20Constructed%20Wetlands%20Design%20Manual_0. Vegetation or macrophytes that are present in the pond should be removed as it may provide a breeding habitat for mosquitoes pdf Waste Stabilization Ponds and prevent light from penetrating the water columnConstructed Wetlands Design Manual]. UNEP-IETC/Danida, Dar es Salaam, TZ/Copenhagen, DK.
==Acknowledgements=={{* Peña Varón, M. and Mara, D. D. (2004). [https:Acknowledgements //sswm.info/sites/default/files/reference_attachments/VARON%202004%20%20Waste%20Stabilistion%20Ponds.pdf Waste Stabilisation Ponds]. Thematic Overview Paper. IRC International Water and Sanitation}}Centre, Delft, NL.
==References and external links==* Shilton, A. (Ed.) (2005). Pond Treatment Technology. Integrated Environmental Technology Series, IWA Publishing, London, UK. (Book)
* Arthurvon Sperling, JPM. (19832007). Notes on the Design and Operation of [https://www.iwapublishing.com/sites/default/files/ebooks/9781780402109.pdf Waste Stabilization Stabilisation Ponds in Warm Climates of Developing Countries. The World Bank+ UNDPBiological Wastewater Treatment Series, Volume Three]. IWA Publishing, London, WashingtonUK.
* Critesvon Sperling, RM. and Tchobanoglousde Lemos Chernicharo, GC. A. (19982005). Small and Decentralized [https://www.iwapublishing.com/sites/default/files/ebooks/9781780402734.pdf Biological Wastewater Management SystemsTreatment in Warm Climate Regions, Volume One]. WCB and McGraw-HillIWA Publishing, New YorkLondon, USAUK. pp. 495-656.
* MaraUlrich, DDA. (Ed.), Reuter, S. (Ed.), Gutterer, B. (Ed.), Sasse, L., Panzerbieter, T. and PearsonReckerzügel, HT. (19982009). Design Manual for Waste Stabilization Ponds [https://wedc-knowledge.lboro.ac.uk/resources/books/DEWATS_-_Chapter_01.pdf Decentralised Wastewater Treatment Systems (DEWATS) and Sanitation in Mediterranean Developing Countries. Lagoon Technology International LtdA Practical Guide].WEDC, Loughborough University, LeedsLeicestershire, EnglandUK.(Detailed description and Excel spreadsheets for design calculations)
* Mara, DD. (1997). Design Manual for Waste Stabilization Ponds in India. Lagoon Technology International Ltd., Leeds, England.===Acknowledgements=== * Sasse, L. (1998). DEWATS{{: Decentralised Wastewater Treatment in Developing Countries. BORDA, Bremen Overseas Research and Development Association, Bremen, Germany. (Detailed description and Excel ® Spreadsheet codes for design.) * von Sperlin, M. and de Lemos Chernicharo, CA. (2005). Biological Wastewater Treatment in Warm Climate Regions. Volume One. IWA, London. pp 495–656.Acknowledgements Sanitation}}