What are the types of sewerage systems?
Sanitary sewers, storm sewers, and combined sewers are the three types of sewers. All three of these sewer systems play critical roles in ensuring that the waste we generate is properly transported and treated.
Sanitary Sewers System
A sanitary sewer's primary function is to transport waste from homes and businesses to wastewater treatment plants. These systems are intended to handle human waste and easily degradable manufactured solids such as toilet paper and tissues. These systems are made up of miles of piping, manholes, and pumping stations that move waste through the system.
Gravity is typically used by sanitary sewers to transport wastewater away. Pumps, on the other hand, are sometimes used in low-lying areas when wastewater needs to reach a higher elevation.
For routine maintenance and repair, sanitary sewers are accessed through manholes. Clean-outs on your property allow you to access the section of the sanitary sewer that runs from your house to the sewer main in the street. If there is a clog in this pipe, it can be accessed through the clean-out.
These sanitary sewage systems work by transporting human waste from the home through small plumbing pipes to gradually larger pipes outside, until it reaches the main sewer line in the street. The sewage is then transported to a wastewater treatment plant, where it is treated and safely returned to the environment.
Storm Sewage Systems
Storm sewers, also known as surface or runoff sewers, collect and transport rainwater, snowmelt, and irrigation runoff into storm drains in parking lots, streets, and gutters. These drains are linked by a network of underground pipes that transport the water directly to rivers, lakes, and other bodies of water without treatment at a treatment plant.
When it rains (or snow melts), water enters storm sewers through manholes, pipes, storm drain inlets, open ditches, and other structures. This water is then carried away, eventually flowing directly into streams, rivers, and waterways without being treated. This is why you should never dispose of hazardous waste through a storm drain. Paint, solvents, used motor oil, and cleaning liquids are examples of such materials. They can pollute rivers, lakes, and wetlands, as well as poison wildlife.
Unlike the sanitary sewer system, which transports waste to a treatment plant, the storm sewer system transports untreated runoff water directly into our environment. Every drop of water that enters that storm drain is discharged into our waterways.
Combined Sewage Systems
These are exactly what they sound like: sewer systems. They are a hybrid of sanitary sewer and storm sewer systems. They are rarely used nowadays due to the potential health risks to people and the environment.
The way combined sewers work is that they collect all of the water from rain and snow into a pipe and then add human waste to the same pipe. In an ideal world, this system would pump these combined wastes to a treatment plant, where they would be safely returned to the environment. Combined sewer overflow events can also result in an excessive amount of wastewater reaching sewage treatment plants. When this happens, the plant is unable to properly treat the wastewater.
Worse, during extreme weather events, combined sewers can cause wastewater – including raw sewage – to back up into occupied buildings. The cost of cleaning up this stinky mess is not trivial.
However, during times of heavy rain or flooding, these systems can back up and overflow, allowing untreated wastewater to enter the environment. As a result, dangerous pathogens and pollutants can enter the environment, posing a serious threat to people's health.
Conclusion
If you need any information about types of wastewater treatment plants best suited for you, get in touch with Netsol water. An expert from our technical sales team can provide any additional information you require.
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