How Does a Biological Wastewater Treatment System Work?

Purpose

Biological treatment systems are designed to remove hazardous materials from wastewater, or otherwise sewage lines. Chemical spills, fat and grease discharges, fecal materials, chemicals, heavy metals and the effects of heavy rains and floods require continuous water treatment applications to maintain safe, usable water supplies. Breaking down contaminants within wastewater is accomplished through a number of applications, one of which includes biological measures. Physical, chemical and biological systems are all needed to ensure required water quality standards.
Wastewater naturally contains a diverse population of microbial bacteria. These bacteria play a large role in helping to remove sewage contaminants by breaking down organic materials. Biological treatment systems work to strengthen these bacteria strains. Because this is a natural process within nature, the risk of altering water molecules is reduced, unlike chemical treatment applications. Water purification needs may vary according to its intended use. Intended uses include drinking water as well as medical, chemical and industrial applications.

How it Works

Nature has a built-in process that initiates the breakdown of waste materials through a biodegradation process. This process uses microorganisms such as bacteria to alter and break down organic materials. In essence, these microbes produce and release the enzymes needed to catalyze the chemical reactions that take place when materials decompose. Because there are a number of bacteria strains involved, these organisms are able to adapt and evolve according to whichever contaminant materials are present.
Mineralization occurs when these organic materials are converted into inorganic forms. Carbon, nitrogen and phosphorous are the three elements that result from mineralization. All three are considered nutrient elements because of their return effects to the environment, and to the bacteria organisms involved in the wastewater treatment process. These biological processes involve aerobic and anaerobic organisms.

System Requirements

Wastewater treatment systems work to remove all impurities, contaminants and solids. To do this, these materials have to be collected, handled and safely disposed of without causing harm to the environment or to humans. The steps involved in completing this process include pretreatment, primary treatment, then secondary and tertiary treatments. Pretreatment involves maintaining a balanced flow of wastewaters throughout an area to prevent blockages. This step also works to precondition the waters so that contaminants are equally distributed throughout.
Primary treatment occurs at the water plant, where solid materials are separated and removed before wastewaters undergo biological treatment. Secondary treatment happens when wastewaters are sent into biological reactor channels where microorganisms work to break down organic materials. Sludge, or floc, is a byproduct of this step, and must be separated and removed in settling tanks. Tertiary, or advanced, treatment removes any remaining materials that are left over from the secondary treatment.

Resources

• Biological Wastewater Treatment Process
• Wastewater Treatment Facility Statistics