Bacteria in the Sewage Treatment Process

Bacteria in the Sewage Treatment Process

The role of bacteria in the sewage treatment process is often misunderstood

A quick review of the biological of bacteria is in order as we start this post. Remember that bacteria may be aerobic, anaerobic or facultative. Aerobic bacteria require oxygen in order to survive and multiply.  Conversely, strict anaerobes not only survive without oxygen, they are killed in the presence of oxygen. Facultative bacteria have the capabilities of both the aerobes and the anaerobes and can live with or with out oxygen.

Since aerobes tend to be more efficient in metabolize the chemical constituents found in wastewater, many sewage treatment plants add oxygen to improve the performance of the aerobic bacteria. By adding oxygen, the aerobes will outcompete the anaerobes. Agitation, settling, pH and other factors are carefully controlled and considered as a means of maximizing the bacterial metabolism of organic components in the wastewater.

It is well known that bacteria multiple by binary fission; that is one cell divides into two cells, two cells divide into fours cells, etc. . Assuming an adequate food (nutrient) supply, and suitable other growth conditions,  bacteria will grow and divide again like the original bacterial cell. Every time a cell splits, approximately every twenty  to thirty minutes, a new bacterial generation occurs. This is commonly known as the exponential or logarithmic growth phase. During this phase, the largest number of bacterial cells are produced in the shortest amount of time.

Most wastewater treatment plants attempt to maximize the the growth conditions for aerobic bacteria thereby reducing the organic components of the wastewater as efficiently and as timely as possible.

Bacteria degrade organic components or use as an energy source and to create new bacteria cells. Bacteria can be thought of as enzyme producing factories and it is these enzymes that are instrumental in metabolizing the organic compounds in sewage treatment process. While enzymes are responsible for degrading the organic compounds, it is important to remember that enzymes cannot reproduce. Because of this fact, the use of enzymes in wastewater treatment is limited.

Microorganisms and their enzyme systems are responsible for many different chemical reactions produced in the degradation of organic matter. As the bacteria metabolize, grow and divide they produce enzymes. These enzymes are high molecular weight proteins.

To function properly, most, if not all, sewage treatment plants are designed to take advantage of the degradation of organic materials by bacterial activity. So the enhancement of bacterial activity will enhance the overall performance of the wastewater treatment plant.

Further, sewage treatment plants take advantage of another characteristic of bacteria; their ability to adapt to ever changing organic constituents. Remember that sewage is ever-changing. Since enzymes are substrate specific, the addition of enzymes alone becomes an impossible task. Bacteria, on the other hand, easily change to their environment. They continue to produce enzymes in order to continue to survive.

Since wastewater treatment plants operate because of bacteria, the addition of specifically selected bacteria can improve overall plant performance. The addition of bacteria in a treatment plant, called bioaugmentation, is generally considered the most reliable and most economical way to improve the performance of a sewage treatment plant.

Custom Biologicals manufactures wastewater treatment bacteria for use in municipal wastewater treatment, industrial wastewater treatment, lift stations, and lagoons. Consider using Custom Biologicals to help you in the sewage treatment process.

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