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In Brazil, 100 mm diameter laterals or branch sewers are being used in residential areas for a maximum length of 400 m. These 100 mm diameter pipes are usually located under the unpaved streets of peri-urban communities. |
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In the simplified system, typical minimum sewer depths are 0.65m below sidewalks, 0.951.50 m below residential streets, depending on the distance from the street centreline and amount of traffic, and 2.5 m below heavily travelled streets. Building elevations are not considered in setting the invert elevation of the sewers. If buildings along the mains are too low to enter the sewer by gravity, it is the responsibility of the property owner to find other means of making a connection. In some cases, where topography permits, it may be possible to connect on the other side of the block if easements can be obtained from the neighbouring owners. |
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Manholes constitute an expensive component of a sewer system. In Brazil, engineers have found that conventional manholes are often unnecessarily expensive. Where possible, conventional |
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| Table 11.3 Type and application of manholes in simplified sewerage | | Application | |
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Design |
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| | Sewer terminus | Terminal cleanout | | Long straight sewer | Inspection cleanout | | Change in slope/diameter | Buried concrete box | | Major junction | Simplified manhole | | Minor junction | Inspection cleanout | | Minor drop | Inspection cleanout | | Major drop | Simplified manhole | | Deep sewer (> 3 m) | Conventional manhole |
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