View source for Settled sewerage (small diameter)

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Settled sewerage, also called small diameter or small-bore sewerage is designed to prevent solids in wastewater from entering a communal small bore sewer network. An important condition for the functioning of these sewer networks is that a minimum average of 25 litres per person per day enters the system. First wastewater settles in a small interceptor tank. Later, wastewater is conveyed via small (50  200 mm) diameter sewers of PVC or other durable material. Pipes are laid at various gradients from 0% to 10%. Inspection manholes are limited to minimise unauthorised opening and disposal into the system. Costs can be reduced if a group of households shares one interceptor tank. Although settled sewerage is mainly used to transport wastewater, small diameter sewers are also appropriate to transport urine. 

[[Image:Settled_sewerage.PNG|thumb|right|150px|[[Settled sewerage (small diameter) |Settled sewerage (small diameter)]], in Egypt (for credits, click the picture)]]

{| border="1" cellpadding="5" cellspacing="0" align="center"
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! width="50%" style="background:#efefef;" | Advantages
! style="background:#e9f5fd;" | Disadvantages
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| valign="top" | Less dependent on active user involvement. <br>
All kind of wastewater can be transported. <br>
Little water needed to transport excreta through the small diameter pipe. <br>
Sewers can be laid at flat gradients. <br>
Excreta `out of sight'. 
| valign="top" | Institutional operation and maintenance required. <br>
Interceptor tanks need to be desludged periodically. <br>
Potential risk of blockages due to illegal connections that by-pass the interceptor tank. <br>
High water consumption for excreta removal. 
|}

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