Water comes out of your taps, and you probably know where the local wastewater treatment plant is if you’ve ever smelled it. But have you have wondered what wastewater treatment plants do? Water is our most precious resource and the one we use the most. Recycling it is important, but you likely don’t see the process in action. Find out more about this hidden operation that supports our communities.
Primary Treatment Stage
Water moves through pipes underground to the sewer, where it eventually makes it to your local wastewater treatment plant. Once the water goes through a screen and finds its way into a chamber, rakes remove the large object like sticks and rags that float on the top. Then, pushers remove stones and other sediment that settles on the bottom.
Next, the wastewater reaches the sedimentation tank, where the speed of flow is slowed so that the remaining matter can fall to the bottom. This solid matter is pumped out and used as fertilizer. One phase of treatment does not bring water to a standard that is high enough for drinking, so another phase is required.
Secondary Treatment Stage
During the secondary treatment phase, sewage is moved to the aeration tank after the final step in the primary stage. Roughly 85 percent of organic matter is removed during this stage. The most common method used during the second treatment phase is known as the activated sludge process or aerobic treatment process. During this process, operators inject oxygen into the water so microorganisms and other bacteria will thrive. The microorganisms break down and consume toxins in the water. To ensure the correct amount of oxygen is being supplied to the water, operators use wastewater flow meters to monitor the dissolution of gases to tanks.
Purifying Drinking Water
The final step in the secondary treatment stage is disinfecting the wastewater. Treatment plants use chlorine to kill pathogens and reduce the odor in your water. Many plants remove the chlorine before returning the water to your home. Wastewater treatment plants near oceans are experimenting with alternative forms of purifying drinking water since chlorine can harm aquatic life. Some plants are using UV light and ozone instead.
Knowing what wastewater treatment plants do can help you make better choices about the water you drink. Investigate your local plant to find out what they do to purify water and keep your environment safe. You need water to live, and it is up to your community to supply you with this necessary resource.