People use water every day in their homes and businesses. Many industrial processes also require water. This used water, called wastewater, contains harmful substances, such as soap, chemicals, oils, human waste, phosphorus, nitrogen and food. Water treatment systems remove these pollutants from wastewater before releasing it back into the environment. The U.S. Geological Survey warns that improperly treated wastewater has adverse effects on human health and the environment.
Function
Aerobic water treatment removes impurities from domestic wastewater by using oxygen to enhance the natural processes of eliminating contaminants from wastewater. Naturally occurring microorganisms, such as bacteria, protozoa, fungi and other microbes, break down contaminants in water. Aerobic water treatment encourages the growth of these microorganisms, according to the University of Tennessee.
Aerobic Process
Aerobic systems treat wastewater in stages. While aerobic treatment units come in a variety of designs, they have common features, including a pretreatment component, aeration tank, disinfection chamber and dispersal field. The pretreatment component, called a trash tank, separates solids from the liquid. The solids settle on the bottom of the tank, while the liquid enters the aeration tank for treatment. The aeration tank circulates oxygen throughout the wastewater, encouraging the growth of bacteria that breaks down the organic material. The treated water enters the disinfection chamber, where a disinfectant, such as chlorine, disinfects it. After disinfection, a pump tank transports the wastewater to the dispersal field.
Advantages
The Oklahoma Department of Environmental Quality identifies numerous advantages of aerobic treatment systems. These systems can replace failing septic systems. They can function in any type of soil condition and do not need a large area. Aerobic treatment systems produce a high-quality effluent by providing a higher level of treatment than a septic system, according to West Virginia University.
Disadvantages
Aerobic treatment systems have various disadvantages, according to the National Association of Home Builders Research Center's website Toolbase. These systems are expensive to install, operate and maintain. The initial installation cost of an aerobic system can be up to several thousand dollars, according to the Toolbase website. Other expenses include electricity for the aeration system and regular maintenance of the system. The Toolbase website warns that failure to regularly service these systems or pouring harmful chemicals down the drain results in damage to system components and improperly treated wastewater.
Considerations
West Virginia University advises homeowners that an aerobic treatment system might be a good option if the soil quality around their homes is not appropriate for a septic system, or the available land for sewage treatment is too small to support a septic system. However, some states and municipalities prohibit the installation of aerobic treatment systems. Regulations concerning these systems vary widely among states and municipalities, so homeowners should contact their local health department for guidelines.
References
- University of Tennessee: Aerobic Treatment of Wastewater and Aerobic Treatment Units
- Barnstable County Department of Health and Environment: Basics of Wastewater Treatment
- Toolbase.org: Aerobic Wastewater Treatment Systems
- West Virginia University: Home Aerobic Wastewater Treatment: An Alternative to Septic Systems
- Oklahoma Department of Environmental Quality: Aerobic Sewage Treatment System
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