Unnecessary and Harmful Levels of Domestic Sewage Chlorination Should Be Stopped
CED-77-108: Published: Aug 30, 1977. Publicly Released: Aug 30, 1977.
- Full Report:
Chlorine discharges by municipal sewage treatment plants sometimes exceed levels safe for the aquatic environment and have sometimes resulted in fish kills and deterioration of aquatic life.
The widespread practice of sewage chlorination was questioned because of: the low risk of disease being transmitted through water other than drinking water; the fact that sewage disinfection is not practiced extensively in other industrialized countries; the low level of improvement in public health resulting from disinfection; and inconclusive results of epidemiological studies of the relation of bacterial levels in swimming waters to illness. Drinking water is purified in water treatment plants and benefits from the disinfection of swimmable waters has not been demonstrated. The Environmental Protection Agency (EPA) has taken some steps to reduce uncontrolled and excessive use of chlorine for wastewater disinfection, and states no longer have to disinfect waste treatment plants' effluent unless necessary for water quality. Criteria for use by the states are not flexible enough and disinfection may still be used regardless of low risk to people. Over-chlorination sometimes results from inefficient chlorination systems.