How does a Sewage Treatment Plant Work?

In the primary stage of treatment very large debris is removed from the sewage such as leaves and limbs by way of screens placed in the path of the moving sewage. Then sediment tanks are used to get the sand and grit out so they don’t damage pumps and other machinery. In the secondary treatment, the water is sent to a bioreactor where microorganisms will eat any organic matter. Then in the final stage called tertiary treatment, the water is purified by one or more of the following; chlorination, by adding ozone, or by ultraviolet radiation.