The Stages of Wastewater Treatment

Water is one of the most precious resources on this planet, which makes the process of wastewater treatment very important. Out of all the water found on earth, only 3% of it is fresh water. To ensure everyone gets an adequate amount of water needed to run their daily activities, wastewater from homes, industries, and commercial facilities goes through specific stages to become useful once again.

So how is wastewater treated? What are the stages involved? This article will help you understand the process of treating wastewater and the effort that goes into ensuring you get healthy, clean water every day.

The Stages of Wastewater Treatment

Three major stages are involved in wastewater treatment processes — Primary, Secondary, and Tertiary. Each stage deals with different pollutants, and water becomes cleaner as it moves through the phases. Let’s discuss these stages in detail.


Before the wastewater enters the primary treatment stage, it is moved through a collection system and mixed with smell-neutralizing chemicals. Next, the wastewater is screened. Screening involves separating large items such as plastics and bottle tops from the water. During primary treatment, the wastewater is held in a settling tank where the heavy solids sink at the bottom while the lighter solids float at the top. These materials will be trapped in the equipment while the remaining liquid moves through to a more rigorous secondary phase.


The secondary treatment involves further removing the soluble organic matter that escaped the primary treatment and breaking down the wastewater further. The secondary treatment is more in-depth as it works to degrade the biological content of waste by using aerobic biological processes. To do this, water equipment pumps air into massive aeration tanks.

Then the tanks mix wastewater with a small amount of sludge, called seed sludge, to enable the growth and development of bacteria and other microorganisms that can feed on the leftover organic matter. The process generates large particles that end up settling at the bottom of the tanks. The wastewater goes through the system for a period of about three to six hours.


The tertiary treatment stage involves the actual removal of wastewater impurities from the supply. During this stage, 99% of impurities have been eliminated, making the water close to safe for drinking. For this stage, wastewater treatment facilities require advanced machinery and chemical feed stations that are powered by system automation to sanitize the water effectively. After this process, the water is released for human consumption through the local waterways.

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Gullett Sanitation Services, Inc. is your number one company for septic systems and dewatering services. We have been serving residential and commercial facilities in Ohio and the surrounding communities for 80 years. If you’re a home or business owner with a septic system and wastewater issues, you can trust our technicians to deliver nothing but the best services. Call us today to know why we’re considered the foremost authority on septic system installation, repair, and maintenance services.