ABSTRACT
The environmental effects of organic pollutants are usually not expressed as direct concentration measurements but as the oxygen-depleting effect on a receiving stream. A critical element in maintaining aerobic systems is supplying sufficient oxygen for cell maintenance and sustaining the oxidation process. Biodegradable organics are consumed by bacteria, the fastest-growing population, with the rate proportional to the available food. They can exist in aerobic, anaerobic, or facultative environments. The bulk of bacteria are facultative, permitting them to exist in either aerobic or anaerobic conditions, allowing them to survive during oxygen-deficiency conditions. The next link in the food chain is the protozoa, which are aerobic, depending on bacteria for their survival. Under extreme overloading, anaerobic conditions can develop at the microorganism surfaces, and the organic itself results in toxic effects from “overactivity.” Toxic materials are an unstabilizing factor in a biological system and of particular concern in industrial waste treatment plants.
