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[[Image:Icon_sewer_discharge_station.png |right|95px80px]]'''A Sewer Discharge Station (SDS) is a point along the sewermain sewer main that can be legally accessed and used for discharging septage and sludge directly into the sewer so that it can be transported to a (Semi-) Centralized Treatment facility. SDSs are intermediate transfer points for sludge that cannot easily be transported to a dedicated treatment facility. Sludge can be dumped in a local SDS rather than either a) dumping it illegally or b) trying to travel to a distant collection point.'''
Sludge is dumped into the SDS and then either released directly to the sewer or held in a temporary storage tank before being released to the sewer at a set time. Timed release can help prevent solids from building up in the sewer line and also help optimize the treatment efficiency of the treatment technology by reducing peak loading.
A variation is a stand-alone Transfer Station that is not connected to a sewer main (for more information, refer to: [[Transfer Station (Underground Holding Tank)]]. When the Transfer Station is full, a vacuum truck must empty the stored contents and take the sludge to a suitable treatment facility. If the municipality or sewerage authority is operating the Transfer Station they may charge for permits to dump in the Transfer Station to offset the cost of maintaining the facility.
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- Reduces transport distance and may encourage more community-level emptying solutions. <br> - May reduce illegal dumping of faecal sludge. <br> - Moderate capital and operating costs; can be offset with access permits. <br> - Potential for local job creation and income generation. | con=
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<br>===Adequacy===
SDSs are especially appropriate for dense, urban areas where there is no alternative discharge point (e.g. faecal sludge thickening pond) and where there is a sewer main. Multiple SDSs in a city may help to reduce the incidence of illegal sewage dumping. The quality and quantity of the faecal sludge will significantly affect the treatment technology that is receiving the sludge.
The system for issuing permits or charging access fees must be carefully designed so that those who most need the service are not excluded because of high costs, while still generating enough income to be sustainable and well-maintained.
===Health Aspects/Acceptance===
SDSs have the potential to significantly increase the health of a community by providing an inexpensive, local solution to faecal sludge and septage disposal. Many informal settlements are located near to, if not directly on top of, a sewer line. By building a legitimate access point, the risk of sewer damage and illegal access points may be reduced. When pits are emptied regularly and illegal dumping is minimized, the overall health of a community can be improved significantly. The location must be carefully chosen to maximize efficiency, while minimizing odours and disturbances to nearby residents.
===Upgrading===
SDSs are relatively common in North America, especially in rural communities where septic tanks are common. There, they are equipped with digital data recording devices to track quantities, input types and origin, as well as collect data from the individuals who dump there. In this way, the facilitators can collect detailed information and more accurately plan and adapt to the changing loads. Maintenance
Racks (screens) must be cleaned frequently to ensure a constant flow and prevent backups. Sand and grit must also be periodically removed from the holding tank. The pad and loading area should be cleaned regularly to prevent smells, flies and other vectors from becoming a nuisance.
===References===
* [http://www.afdb.org African Development Fund] (2005). [http://www.afdb.org/fileadmin/uploads/afdb/Documents/Project-and-Operations/GH-2006-010-EN-ADF-BD-WP-GHANA-AR-ASIP.PDF Accra sewerage improvement project- appraisal report]. Infrastructure Department Central and West Regions.
* USEPA (1994). [http://www.epa.gov/nrmrl/pubs/625r94002.html Guide to Septage Treatment and Disposal: EPA/625/R-94/002]. United States [http://www.epa.gov Environmental Protection Agency], Office of Research and Development, Cincinnati, Ohio, USA.
===Acknowledgements===
{{:Acknowledgements Sanitation}}