Sewer Water Treatment System

When you flush your toilet, do you ever wonder where the waste water goes? What about why it goes there? Where it goes is a water treatment plant. Why it goes there is to keep us all safe from the harmful bacteria that can live in the waste we produce. Here’s how.

Septic Tanks

If you live in a rural area where sewers would be too costly to install, you get your own mini-sewer, also referred to as a septic tank. Your waste water flows from your house into the septic tank and is given time to settle the heavier elements to the bottom. The cleaner water is slowly allowed to leak back into the ground near the top of the septic tank. Occasionally a product such as Rid X is needed to break down the waste sediment in the septic tank.

Sewer Systems

If you live in a city, your sewers are more communal. Your water will drain to a main catch-all canal. This canal will be a slow-moving river of debris and sediment that gravity will cause to settle to the bottom. Eventually the water will reach a water filtration plant, where more filtration will occur thanks to gravity and chemicals before the water is released back into the environment, where it can be filtered naturally and return to our spigot.


What if we didn’t have these sanitation devices in place? Human waste is full of nitrogen and phosphorous. These nutrients are excellent for plant life. However, if they are released into water, they will cause the algae population to explode. The numbers of algae soon become unsustainable and they die. The decomposition of the algae leads to the removal of oxygen in the water they had grown in, killing the animals beneath the water.

Nitrogen Removal

Our atmosphere is made up of mostly nitrogen, so getting nitrogen back into the air is a good goal. The process to achieve this is called biological oxidation. The process basically entails separating the ammonia (nitrogen and hydrogen) from the water by combining the hydrogen in the ammonia and releasing the nitrate, which is then condensed into nitrogen gas. The nitrogen gas then goes back into the atmosphere.

Phosphorous Removal

Phosphorous removal is usually done with chemical precipitation. The phosphorous nutrients collect around a solid that is put into the water (such as salt or iron) and gather around it. Then the new compound is filtered out of the water. The only drawback to phosphorous removal is that it can produce a lot of sludge. However, this sludge can be turned into fertilizer for use with land plants.