Sewage treatment plants
Complexes consisting of devices and facilities for removing contamination from wastewater and disposal of the sludge resulting from their treatment.
The main function of a water treatment plant is to accelerate the natural processes of water purification.
Wastewater may be divided into municipal water treatment plants and industrial wastewater treatment plants. The former are suited for treating mixed grey and black water. The latter type is suited for treating wastewater generated in industrial processes.
There are two basic stages of waste treatment – primary and secondary. The first treatment stage, called the initial stage, consists of simple mechanical operations (e.g. filtration, aeration) and physical processes (e.g. sedimentation). They remove larger solids, granules, oils and fats from the wastewater. The second stage uses biological and chemical processes at the same time. Contaminants are removed from the wastewater in the process of biological oxidation in the presence of microorganisms. Wastewater containing organic chemicals and heavy metals are treated using the physicochemical and chemical method. They include coagulation, neutralization, extraction, sorption, electrolysis and distillation.
