Have you ever wondered what happens to the water and waste after you flush or pull the plug on your bathtub? Most citizens enjoy the benefits of the city’s wastewater treatment without realizing all that goes on behind the scenes of this rather fascinating and complex process involving chemistry, technology, and a team of dedicated professionals.
Wastewater flushed from homes and commercial businesses flows through a city’s sanitary sewer collection system to a lift station. The lift station then pumps it to the treatment plant through force mains to gravity lines. The City of Alvin’s wastewater system consists of 44 lift stations and associated force mains, a wastewater treatment plant and a network of gravity and force mains.
Untreatable materials are physically removed by way of screenings and grit removal which separate the sand and other inorganic material that may harm the pumps and other equipment in the treatment process.
Primary treatment involves filtration and settling procedures. Approx 50% of the pollutants are removed during this stage. Sedimentation is the process where solids and liquids are gravitationally separated, the thickened solids naturally settle to the bottom of the clarifier.
This is the biological process which removes 85% to 90% of the remaining pollutants. The two most common types of secondary treatment are attached growth processes and suspended growth processes. Trickling filters and activated sludge are examples of these two types of treatment. Both processes create conditions favorable to the growth and reproduction of helpful microorganisms which consume most of the waste material. The microorganisms then settle out of the treated water in the secondary settling tank or clarifier.
This is the final process prior to discharge or release of treated water. This step ensures any disease-causing microorganisms are killed and the water released into Chocolate Bayou is safe for the environment and human life.
Following stringent regulations, laboratory tests are performed and monitored to ensure that state and federal regulations are met.
BIOSOLIDS AND COMPOSTING
The Alvin Wastewater Treatment Plant utilizes a belt filter press to separate solids and liquids. The solid material removed during the treatment process is called sludge. Dewater biosolids are sent to a third-party composting facility.
WASTEWATER TREATMENT OPERATORS ARE FIRST RESPONDERS
Wastewater treatment is a life-saving service and an essential public health safeguard. The City of Alvin employees highly trained individuals that tirelessly work to keep residents safe while protecting the environment from deadly pollutants. When an emergency event such as extreme weather happens, these trained professionals are ESSENTIAL personnel needed to ensure the continued functionality of the wastewater treatment.