Abstract
The authors examined the influence of fluorine as a factor disrupting the processes of municipal sewage biological treatment. Sodium fluoride was introduced to a municipal plant sewage treated in an oxygen zone, acting as a simulator of uncontrolled industrial sewage discharge. The influence of fluoride ion concentration and the duration of sewage treatment on its biological purification processes were examined. Also, the dependencies of the direction of changes in inorganic nitrogen connections, phosphorus concentration, COD and fluorine on the initial fluorine compound content in the purified sewage were determined. Research samples of the municipal sewage were drawn at the opening of the oxygen zone in a typical municipal sewage treatment plant (RLM > 100 000) employing intensified biogenic substance removal.