Study on a treatment process of atmospheric precipitation for needs of reverse water supply

Increasing attention is paid to issues related to improvement of ecological safety of metallurgical production. The use of atmospheric precipitation as a source of make-up or process water is a currently very relevant and actively developing field of study. To ensure a due level of the quality of atmospheric precipitation, there are various conventional processes of treatment. Coagulation and filtration are primary processes of water treatment for the most types of drinking, domestic and industrial water. It has been found that composite titaniumcontaining coagulants can be used to efficiently remove mechanical impurities from water, and residual content of suspended matters is 0.35 mg/dm3. Residual concentration of impurities for the most wide-spread coagulant, aluminum oxychloride, was 0.45 mg/dm3. It has been proved that the use of the composite titanium-containing coagulant and iron chloride results in minimum secondary water pollution with coagulant anions; however, the use of iron compounds is not advisable due to occurrence of highly abrasive, finely dispersed iron hydroxide in water. It has been established that to achieve minimum residual concentrations of suspended matters, it is feasible to use ceramic or polymer micro-filters. Using mesh or conventional filters with sand or polymer filtering materials is not efficient due to occasional passage of suspended matters into treated water. Atmospheric precipitation treated with coagulation and filtration can be used for make-up water of reverse water supply systems, heat engineering needs or as category 2 water delivered to galvanic facilities.