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The environmental effects of dumping raw sewage

Raw sewage includes the flushings from toilets, the water that drains from sinks, bath tubs, showers, and other faucets in a home. The total collection of water leaving a home after use is called wastewater or raw sewage. Because of the large amount of water we use to wash away waste, our sewage is about 1000 parts of water for every 1 part of waste. Up through the 1970's, numerous locations in the United States dumped their sewage into the local waterways without treating it first. The Clean Water Act of 1972 aimed to clean up the nation's waterways and develop a system of sewage treatement plants that treated waste water before it was released back into the streams and rivers.

The results of dumping raw sewage prior to the 1970's included contamination of water with pathogens (disease causing bacteria, viruses, and other organisms), the killing of aquatic life, and the contamination of drinking water. Included in waste water are debris such as trash that are flushed down toilets or washed down storm drains, organic material, dissolved organic material, and other contaminents such as pesticides, soaps, heavy metals, and other toxic compounds.

The gentleman who owns the sewage collection company described in the "Sewage Dumping" scenario empties private septic tanks that are not connected to city sewer lines. This waste has to be removed from a septic tank and transported to a treatment facility. By dumping sewage into the stream he may be releasing all or some of the above mentioned contaminants into the waterway. The effects may be a decrease in dissolved oxygen because of the increase in bacteria that breakdown the waste and use up oxygen in the process. A decrease in dissolved oxygen would effect aquatic species such as fish and macroinvertebrates. The release of excess nitrogen and phosphorus from the dumped sewage may cause eutrophication and might cause an increase in algal growth.




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