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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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sys9=|
pic=Sedimentation_thickening_ponds.png|
ApplHousehold=|
ManShared=|
ManPublic=XX|
Input1=Faecal Sludge |Input2= |Input3= | Input4= |Input5=|Output1= Effluent | Output2= Faecal Sludge | Output3= | Output4= | Output5=
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|[[Image:Sedimentation_thickening_ponds.png |right|500px]]
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[[Image:Icon_sedimentation_thickening_ponds.png |right|80px]]
'''Sedimentation or Thickening Ponds thickening ponds are simple settling ponds that allow the sludge to thicken and dewater. The effluent is removed and treated, while the thickened sludge can be further treated in a subsequent technology.'''
<br>Faecal sludge is not a uniform product and , therefore, its treatment must be specific to the characteristics of the specific sludge. In generalSludge, there are two types of faecal sludges: high strength (originating from latrines and unsewered public toilets) and low strength (originating from [[Septic Tank|Septic Tanks]]. High strength sludge which is still rich in organics and has not undergone significant degradation, which makes it is difficult to dewater. Low strength Conversely, sludge that has undergone significant anaerobic degradation and , is more easily dewatered. In order to be properly dried, high strength sludges fresh sludge rich in organic matter (e.g., latrine or public toilet sludge) must first be stabilized. Allowing the high strength sludge to degrade anaerobically in Settlingsedimentation/Thickening Ponds thickening ponds can do this. The same type of pond can be used to thicken low strength sludgewhich is already partially stabilized (e.g., originating from [[Septic Tank|Septic Tanks]], S.9), although it undergoes less degradation and requires more time to settle. The degradation process may actually hinder the settling of low strength sludge because the gases produced bubble up and re-suspend the solids. To achieve maximum efficiency, the loading and resting period should not exceed 4 to 5 weeks, although much longer cycles are common. When a 4-week loading, and 4-week resting cycle is used, total solids (TS) can be increased to 14% (depending on the initial concentration). As the sludge settles and digests, the supernatant must be decanted and treated separately. The thickened sludge can then go on to be dried or further composted further.
===Design Considerations===
Two tanks operating in parallel are required; one can be operated, while the other is emptied. To achieve maximum efficiency, loading and resting periods should not exceed 4 to 5 weeks, although much longer cycles are common. When a 4-week loading and 4-week resting cycle is used, total solids (TS) can be increased to 14% (depending on the initial concentration).
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{{procontable | pro=
- Thickened sludge is easier to handle and less prone to splashing and spraying <br>- Can be built and repaired with locally available materials. <br> - Low Relatively low capital costcosts; low operating cost. <br> - Potential for local job creation and income generation. costs <br> - No electrical energy is required. | con=- Requires a large land area <br> - Odours and flies are normally noticeable. <br> - Long storage times. <br> - Requires front-end loader for monthly desludging. <br> - Requires expert design and operation.construction <br>- Effluent and sludge require further treatment
}}
===Appropriateness===
Sedimentation/thickening ponds are appropriate where there is inexpensive, available space located far from homes and businesses; it should be established at the border of the community. The thickened sludge is still infectious, although it is easier to handle and less prone to splashing and spraying. Trained staff for operation and maintenance is required to ensure proper functioning. This is a low-cost option that can be installed in most hot and temperate climates. Excessive rain may prevent the sludge from properly settling and thickening.
==Adequacy== Settling/Thickening Ponds are appropriate where there is inexpensive, available space that is far from homes and businesses; it should be on the edge of the community. The sludge is not hygienized and requires further treatment before disposal. Ideally this technology should be coupled with an onsite [[Planted Drying Beds|Drying]] or [[Co-composting]] facility to generate a hygienic product. Trained staff for operation and maintenance is required to ensure proper functioning. This is a low-cost option that can be installed in most hot and temperate climates. Excessive rain may prevent the sludge from properly settling and thickening. ==Health Aspects/Acceptance=== The Both the incoming and thickened sludge is are pathogenic; therefore, so workers should be equipped with proper protection (boots, gloves, and clothing). The thickened sludge is also infectious, although it is easier to handle not sanitized and less prone to splashing and sprayingrequires further treatment (at least in a drying process) before disposal or end-use. The pond ponds may cause a nuisance for nearby residents due to bad odours and the presence of flies. ThereforeThus, the pond they should be located sufficiently away from urban centres. ==Maintenance== Maintenance is an important aspect of a well-functioning pond, although it is not intensive. The discharging area must be maintained and kept clean to reduce the potential for disease transmission and nuisance (flies and odours). Grit, sand, and solid waste that are discharged along with the sludge must be removed. The thickened sludge must be removed mechanically (front end loader or specialized equipment) when the sludge has thickened sufficientlyresidential areas.
===Operation & Maintenance===
Maintenance is an important aspect of well-functioning ponds, but it is not intensive. The discharging area must be maintained and kept clean to reduce the potential of disease transmission and nuisance (flies and odours). Solid waste that is discharged along with the sludge must be removed from the screen at the inlet of the ponds. The thickened sludge must be mechanically removed (with a front end loader or other specialized equipment) after it has sufficiently thickened.
===References===* Heinss, U., Larmie, S. A. and Strauss, M. (1998). [https://sswm.info/sites/default/files/reference_attachments/HEINSS%201998%20Solids%20Separation%20and%20Pond%20Systems%20For%20the%20Treatment%20of%20Faecal%20Sludges%20In%20the%20Tropics.pdf Solids Separation and Pond Systems for the Treatment of Faecal Sludges in the Tropics – Lessons Learnt and Recommendations for Preliminary Design. 2nd Ed. Report 05/98]. Eawag (Department Sandec), Dübendorf, CH.
* Elizabeth Tilley etHeinss, U., Larmie, S. A. and Strauss, M.al (20081999). [httphttps://wwwsswm.eawag.ch/organisation/abteilungeninfo/sandecsites/publikationendefault/publications_sespfiles/downloads_sespreference_attachments/compendium_highHEINSS%20et%20al%201994%20Characteristics%20of%20Faecal%20Sludges%20and%20their%20Solids-Liquid%20Seperation.pdf Compendium Characteristics of Sanitation Systems Faecal Sludges and TechnologiesTheir Solids-Liquid Separation] . Eawag ([http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_sesp/downloads_sesp/compendium_low.pdf low res version]). Department of Water and Sanitation in Development Countries ([http://www.sandec.ch/ Sandec]) at the Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf, CH. (Provides a full overview of sanitation systems.)
* HeinssMontangero, U., Larmie, SAA. and Strauss, M. (19992002). Characteristics of Faecal Sludges and their Solids-Liquid Separation. Eawag/Sandec Report, Dübendorf, Switzerland. Available: http[https://www.eawag.ch/fileadmin/Domain1/Abteilungen/sandec/publikationen/EWM/Articles/SN05_FSM.pdf Faecal Sludge Treatment]. Lecture Notes, UNESCO-IHE, Delft, NL.ch
* HeinssStrande, UL., LarmieRonteltap, SAM. and StraussBrdjanovic, MD. (Eds. ) (19982014). Solids Separation and Pond Systems for the Treatment of Faecal Sludges in the Tropics[https://www.un-Lessons Learnt and Reccomendations for Preliminary Design. Second Editionihe. Eawagorg/Sandec Report 05sites/98, Dübendorf, Switzerland. Available: http:default/files/wwwfsm_book_lr.pdf Faecal Sludge Management. Systems Approach for Implementation and Operation].sandecIWA Publishing, London, UK.ch(Detailed book compiling the current state of knowledge on all aspects related to FSM)
