ABSTRACT
The waters, used for purposes of drinking, are natural fresh waters, mostly from surface water bodies and partially from underground sources. The natural water is characterized by the diversity of its composition. Coagulation finds wide application in water treatment processes, especially for preparation of drinking water from the natural waters. The drinking water treatment techniques are aimed at breaking the aggregative stability of impurities, thus enabling their removal from water, either partially, or in full. It can be achieved by the addition of coagulating agents, such as aluminum sulfate, ferric and ferrous sulfates, ferric chloride, aluminum chloride, sodium aluminate, aluminum hydroxychlorides, aluminum hydroxysulfates, or other substances facilitating breakage of the aggregative stability. The process of water treatment by coagulating agents consists of the following main operations: storage of reagents, preliminary water clarification, water alkalization, coagulating agent preparation and its mixing with the treated water, water decoloration, and clarification.
