Changes

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]]|

 '''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.'''

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 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 efficiencyAs the sludge settles and digests, the loading supernatant must be decanted and resting period should not exceed 4 to 5 weeks, although much longer cycles are commontreated separately. When a 4-week loading, and 4-week resting cycle is used, total solids (TS) The thickened sludge can then be increased to 14% (depending on the initial concentration)dried or further composted.

As ===Design Considerations=== Two tanks operating in parallel are required; one can be operated, while the sludge settles other is emptied. To achieve maximum efficiency, loading and digestsresting periods should not exceed 4 to 5 weeks, the supernatant must be decanted although much longer cycles are common. When a 4-week loading and treated separately. The thickened sludge 4-week resting cycle is used, total solids (TS) can then go be increased to 14% (depending on to be dried or composted furtherthe initial concentration).

- 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

===AdequacyAppropriateness=== SettlingSedimentation/Thickening Ponds thickening ponds are appropriate where there is inexpensive, available space that is located far from homes and businesses; it should be on established at the edge border of the community. The thickened sludge is not hygienized still infectious, although it is easier to handle and requires further treatment before disposal. Ideally this technology should be coupled with an onsite [[Planted Drying Beds|Drying]] or [[Co-composting]] facility less prone to generate a hygienic productsplashing 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. ===Health Aspects/Acceptance=== The incoming sludge is pathogenic, so workers should be equipped with proper protection (boots, gloves, and clothing). The thickened sludge is also infectious, although it is easier to handle and less prone to splashing and spraying. The pond may cause a nuisance for nearby residents due to bad odours and the presence of flies. Therefore, the pond should be located sufficiently away from urban centres. ===Maintenance===

Maintenance ===Health Aspects/Acceptance=== Both the incoming and thickened sludge are pathogenic; therefore, workers should be equipped with proper protection (boots, gloves, and clothing). The thickened sludge is an important aspect of not sanitized and requires further treatment (at least in a welldrying process) before disposal or end-functioning pond, although it is not intensiveuse. The discharging area must be maintained ponds may cause a nuisance for nearby residents due to bad odours and kept clean to reduce the potential for disease transmission and nuisance (presence of flies and odours). GritThus, sand, and solid waste that are discharged along with the sludge must they should be removedlocated sufficiently away from residential 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 mechanically (with a front end loader or other specialized equipment) when the sludge after it has sufficiently thickened sufficiently.

* Heinss, U., Larmie, SAS. A. and Strauss, M. (1999). [http://www.sswm.info/sites/default/files/reference_attachments/HEINSS%20et%20al%201994%20Characteristics%20of%20Faecal%20Sludges%20and%20their%20Solids-Liquid%20Seperation.pdf Characteristics of Faecal Sludges and their Their Solids-Liquid Separation]. Eawag/(Department Sandec), Dübendorf, CH.:Available at: [http://www.sandec.ch Sandecsandec.ch] Report, Dübendorf, Switzerland.

* HeinssMontangero, U., Larmie, SAA. and Strauss, M. (19982002). [http://wwwFaecal Sludge Treatment.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 TropicsLecture Notes, UNESCO-Lessons Learnt and Reccomendations for Preliminary Design]IHE, Delft, NL. Second Edition. Eawag/:Available at: [http://www.sandec.ch Sandecsandec.ch] Report 05/98, Dübendorf, Switzerland.

* MontangeroStrande, AL., Ronteltap, M. and StraussBrdjanovic, MD. (2002Eds.) (2014). Faecal Sludge TreatmentManagement. Systems Approach for Implementation and Operation. Lecture NotesIWA Publishing, IHE DelftLondon, UK. (Detailed book compiling the current state of knowledge on all aspects related to FSM):Available at: [http://www.sswmsandec.info/sites/default/files/reference_attachments/EAWAG%20SANDEC%202008%20Module%205%20FSM%20Lecturech sandec.pdf Faecal Sludge Managementch].