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'''A Solids-Free Sewer is a network of small diameter pipes that transports solids-free or pre-treated wastewater (such as [[Septic Tank]] or settling tank effluent) to a treatment facility for further treatment or to a discharge point. Solids-Free Sewers are also referred to as settled, small-bore, small-diameter, variable-grade gravity, or septic tank effluent gravity sewers.'''
The septic/interceptor tank must be regularly maintained and desludged to insure optimal performance of the Solids-Free Sewer network. If the pre-treatment is efficient, the risk of clogging in the pipes is low, but some maintenance will be required periodically. The sewers should be flushed once a year as part of the regular maintenance regardless of their performance.
==Acknowledgements=={{:Acknowledgements Sanitation}} ==References and external links==
* Azevedo Netto, MM. and Reid, R. (1992). Innovative and Low Cost Technologies Utilized in Sewerage. Environmental Health Program, Technical Series No. 29. Pan American Health Organization, Washington DC. (A Short summary and component diagrams-Chapter 5.)
* Otis, RJ. and Mara, DD. (1985). The Design of Small Bore Sewer Systems (UNDP Interreg. Project INT/81/047). TAG Technical Note No.14. United Nations Development Programme + World Bank, Washington. Available: www.wds.worldbank.org (Comprehensive summary of design, installation and maintenance.)
==Acknowledgements==
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