In general, an area that is largely misunderstood in industrial wastewater treatment is the role played by bacteria, both indigenous and applied via bioaugmentation. With few exceptions, most industrial wastewater treatment of organic compounds is intended to take advantage of the natural processes of wastewater treatment bacteria.
Bacteria may be aerobic, anaerobic or facultative anaerobes. Aerobic bacteria require oxygen to perform their metabolic functions and reproduce. Anaerobes cannot live and reproduce in the presence of oxygen. Facultative bacteria have the ability to live either in the presence or absence of oxygen. For the purposes of our discussion, we’ll talk about aerobic bacteria and discouraging or controlling the anaerobes.
In the typical industrial wastewater treatment facility, air is added to improve the metabolism and functioning of the aerobic bacteria. This addition of air is also done to enhance the aerobes at the expense of the anaerobes. A number of factors are controlled at an industrial wastewater treatment plant. All of them with the idea of improving the environmental conditions for the native bacteria. Conditions that are sometimes controlled are:
Bacteria may be classified in a number of ways like size, shape, genus, species, etc. We’ll keep it general in our conversation and say that all of the organisms that we’re talking about are single celled prokaryotic, organisms. These single-celled organisms grow and when they reach a certain size they divide, becoming two organisms. They term used for bacterial reproduction is binary fission. During binary fission, both new cells are identical to the original cell and identical to each other. If there is a sufficient food supply, they grow and divide again. Every time a single bacteria cell divides, we have a new generation.
Its important to point out that the bacteria are not “thinking” about this process. Nor are they trying to accomplish something. The only thing on their mind is to reproduce.
Every time a bacterial cell splits, we have a new generation. This binary fission takes place every 20-30 minutes for many aerobic bacteria. This is known as exponential or logarithmic growth phase and is a key for the use of bacteria in the industrial wastewater treatment process.
This logarithmic growth is a function of two key variables; environment and food. The pattern which results is known as the bacterial growth rate curve. This typical growth rate curve is a result of the four following phases of bacterial life:
End Part 1 The Role of Bacteria in the Industrial Wastewater Treatment Process.
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