sanitary sewer or "dirty funnel" is a special subway system for transporting waste from homes and commercial buildings through pipes to processing or disposal facilities. Sanitary disposal channels are part of an overall system called sewerage or sewerage systems.
Waste can be treated to control water contamination before discharge to surface water. Sanitary disposal channels serving industrial areas also carry industrial wastewater.
A separate sanitary disposal system is designed to transport only waste. In cities served by sanitary channels, separate storm ducts can bring surface runoff directly to the water surface. Sanitary disposal channels are distinguished from combined sewers, which combine waste with stormwater runoff in a single pipe. Sanitary sewer systems are useful because they avoid the combined sewer.
Video Sanitary sewer
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Waste treatment is less effective when sanitary waste is diluted with rainwater, and combined waste streams occur when runoff from heavy rain or snow melt exceeds the hydraulic capacity of the sewage treatment plant. To overcome these losses, some cities are building separate sanitation channels to collect only municipal wastewater and exclude rainwater runoff collected in separate rainwater drains. The decision between a combined sewer system or two separate systems is primarily based on the need for waste treatment and the cost of providing care during heavy rain events. Many cities with combined sewer systems built before installing sewage treatment do not replace the sewer system.
Maps Sanitary sewer
Type
Conventional gravity channel
In developed countries, sewers are pipes from buildings to one or more levels of larger underground mains, which transport waste to waste treatment facilities. Vertical pipes, usually made of precast concrete, called manholes, connect the electricity to the surface. Depending on the application and use in place, these vertical pipes may be cylindrical, eccentric or concentric. Gutters are used for access to sewer pipes for inspection and maintenance, and as a means to vent a gas drain. They also facilitate vertical and horizontal angles in the pipeline straight.
Pipes that deliver waste from individual buildings to common gravity channels are called lateral. The branching gutters usually run under the streets receiving goods from buildings along the way and being dumped by gravity into drains in manholes. Major cities may have gutters called interceptors that receive streams from multiple drains.
The design and size of the sanitary sewers consider the population to be served during the anticipated life of sewerage, wastewater production per capita, and flow culminating in the time of day-to-day routine. Minimum sewer diameter is often determined to prevent clogging by solid materials that are watered down the toilet; and gradients may be selected to maintain flow velocity resulting in sufficient turbulence to minimize solid deposit in the sewer. Commercial and industrial wastewater flows are also considered, but the transfer of surface flow to the storm channel eliminates the peak of wet weather flows from inefficient combined sewers.
Force power
Pumps may be needed where gravity culverts serve areas at lower altitudes than wastewater plants, or distant areas at the same height. Lift stations are sewer drains that remove accumulated dirt to higher altitudes. Pumps can be discharged to another gravitational channel at that location or can flow through the main pressurized power to some distant location.
sewerage
Sewerage systems, also called septic tanks (STED) or solid-waste disposal (SFS) sewer systems, have septic tanks that collect waste from residential and business, and waste discharged from the tank is sent to centralized sewage treatment plants or distributed care system for further treatment. Most solids are discharged by a septic tank, so the processing plant can be much smaller than regular plants. In addition, due to the large reduction in solid waste, pump systems can be used to move waste water rather than gravity systems. The pipe has a small diameter, usually 1.5 to 4 inches (4 to 10 cm). Due to the pressurized waste stream, they can be placed just below ground level along the contours of the soil.
Simplified channel
Simple sanitary channels consist of small diameter pipes, usually about 100 millimeters (4 inches), often placed on a fairly flat gradient (1 in 200). Although the investment cost for a simplified sanitation channel can reach half the cost of conventional sewerage, the requirements for operation and maintenance are typically higher. Simple sewers are the most common in Brazil and are also used in a number of other developing countries.
Vacuum drain duct
In lowland communities, wastewater is often delivered by vacuum drains. Pipe lines range in size from 6-inch (150 mm) diameter pipes to concrete-lined tunnels up to 30 feet (9 m) in diameter. The low pressure system uses a small grinder pump located at every point of connection, usually home or business. Sewage systems use differential atmospheric pressure to move liquids to a central vacuum station.
Maintenance
Overflow of sanitary sewer can occur due to blocked or damaged drainage, excessive rainfall infiltration or pump damage. In these cases untreated waste is discharged from sanitation to the environment prior to reaching the sewage treatment facility. To avoid this, care is required.
Treatment requirements vary with the type of sanitary channels. In general, all water channels worsen with age, but infiltration and inrush are a unique issue for sanitation channels, because combined sewer and storm drains are sized to carry this contribution. Holding infiltration to an acceptable level requires a higher standard of maintenance than is necessary for consideration of the structural integrity of the combined sewer. A comprehensive construction inspection program is required to prevent unsuitable connections from the cellar, yard, and roof ducts to the sanitary sewer. Improper connection probabilities are higher when combined sewer and sanitary channels are found in close proximity, as construction personnel may not recognize the difference. Many older cities still use a joint sewer while nearby suburbs are built with separate sanitary channels.
For decades, when sanitary disposal pipes crack or have other damage, the only option is costly digging, removal and replacement of damaged pipes, usually requiring repetition afterwards. In the mid-1950s a unit was created in which two units at each end with a special cement mixture were pulled from one hole cover to the next, coating the pipe with cement under high pressure, which then healed rapidly, closing all the cracks. and broke in the pipes. Today, similar methods using epoxy resins are used by some cities to re-line aging or damaged pipes, effectively creating "pipes in pipes". This method may not be suitable for the location where the full diameter of the original pipe is required to bring the expected flow, and it may be an unwise investment if a larger flow of wastewater can be anticipated from population growth, increased water use, or new service connections in the expected. life improvement service.
Another popular method of replacing old or damaged channels is called burst pipes, where a new pipe, usually PVC or ABS plastic, is pulled through the old pipe behind the "expander head" that breaks the old pipe because the new pipe is pulled through behind it.
This method is best suited for the parent channels, since the repair of the channel with the lateral connection is complicated by making provision for receiving lateral flow without receiving unwanted infiltration of unsealed joints.
History
The sanitary sewers evolved from the combined sewer drainage where the water was plentiful. Animal waste accumulates in city streets while animal-powered transport moves people and goods. The accumulation of animal feces pushes the dumping of pots into the streets where the night soil collection is impractical. A combined gutter is built to use surface runoff to flush garbage from the streets and move it underground to a place away from the population. Waste treatment becomes important as the population increases, but the increased volume and pumping capacity required for the treatment of diluted sewage from the combined sewer is more expensive than pure waste processing.
See also
- Blackwater (waste)
- Greywater
- Sewerage
- Mining sewers
- Stormwater
- Water pollution
References
Source of the article : Wikipedia
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