Treatment of Liquid Wastes
Microorganisms can be used to help maintain acceptable levels of wastes in our aquatic ecosystem. Everyday human activities produce liquid wastes which flow through natural drainage patterns or sewers, eventually entering natural bodies of water. Natural waters have the ability to purify themselves of these wastes through the activities and interactions of microbial populations. Only reasonably low amounts of raw sewage can be accepted by natural waters without causing a significant decrease in water quaility. High levels of human activity result in high production of liquid wastes which exceeds the capactity of self-purification of these bodies of water. In order to maintain a reasonable level of water quality, the aquatic ecosystem should not be overexposed to organic or inorganic nutriets, or with toxic, noxious or aestheticlly unacceptable substances. Special attention should be given to the oxygen level, temperature, salinity, turbidity and pH so that the water is fit for aquatic life and recreational activity. There are several alternatives to water treatment. Some important methods are listed below:
Sewage Treatment
Oxidation Ponds
Trickling Filter
Activated Sludge
Anaerobic Digesters
Tertiary Treatment
Disinfection
Treatment of Pollutants
Due to the excessive use of fossil fuels by humans in the last century, compounds that microorganisms are not accustomed to have been introduced to the atmosphere. Mircoorganisms are not prepared to biodegrade these toxic substances. Sewage treatment and water purifictaion systems are usually incapable of removing these substances if they enter municipal water supplies. There are examples, however, when these compounds have caused environmental problems and bioremediation has been a successful solution. These include the following:
Alkyl Benzyl Sulfonates (ABS)
Chlorinated Hydrocarbons
Oil Pollutants
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Reference: Principles of Microbiology, R.M. Atlas, Mosby-Year inc., 1995Created by Gianna Aiezza and Meredith Streeter, November 1997