Every time you flush a toilet, take a shower or wash your hands you are creating sewage, also known as wastewater. Often times many people do not understand why wastewater cannot be dumped outside the house. When it comes to this water there are three main reasons for why you do not want to release it outside.
It smells bad.
It is home to harmful types of bacteria.
Contains suspended solids and chemicals from getting into the environment.
But many people are unaware of how it works.
What is it?
Sewer lining systems are mainly used in areas where people are living close together, such as urban or suburban areas. This is due to the amount of water there is to treat. Which means that a community as a whole has built a sewer system that collects water and transports it to a treatment facility.
How Does it Work?
An ideal system is completely gravity-powered. Pipes from every house and buildings will flow down to the main sewer line repairing. This main line ranges from 3 to 5 feet In diameter. In order to maintain these lines, there are some vertical pipes that run from the main line to the surface. These opening are covered by manhole covers, which makes it easy for maintenance workers to get down to there.
All main sewer lines then start to flow into larger pipes, until they reach the wastewater treatment plant. This plant is usually located in a low-lying area because this will help gravity do its job.
Sometimes this gravity based system cannot always work. These instances, the system will have a grinder pump or a lift station. These pumps and lifts will help move everything up hill.
When the water reaches the plant it goes through several different stages of treatment.
First Stage: Known as the primary treatment, this stage works similarly to septic tanks. At this stage, solids will be shifted out. This is done by using a set of pools that will let water sit so that solids can settle out. The solids are then collected and taken off to a landfill or incinerator. Primary treatment stage is able to remove half of the solids, bacteria and organic materials from the wastewater.
Second Stage: This stage works to remove organic materials and nutrients that are left in the water. It is put into tanks that have bacteria in them. This bacteria then starts to consume everything that gets in its way. Once that has happened, it is then moved to settling tanks, so that the added bacteria can settle out. This secondary stage can remove up to 90% of solids and organic materials.
Third Stage: This stage will vary depending on the community and the structure of the wastewater. During this stage, chemicals will be used to remove nitrogen and phosphorous from the water. Adding chlorine to the water will kill any bacteria that is still in it. Before it is transported out it undergoes many tests to make sure that it is okay.