Return of filter washings and sludge treatment at the Western Filtration Plant of Ekaterinburg

Summary

In order to abandon discharging polluted filter washings into the water source a system of filter washings treatment in ultrafiltration membranes for reusing was developed alongside with a unit for the treatment of sludge generated at the filtration facilities. The method of ultrafiltration is at the heart of the filter washings treatment technology. Filter washings from the main process line are filtered through special membranes that provide for the separation into clean water (permeate) and concentrate (sludge). The sludge from horizontal clarifiers of the main process line and the sludge from the ultrafiltration unit are removed to the sludge treatment facilities. Precipitated sludge with a moisture content of 98.5% is removed by the scraper system into the sump whereof it is transported further to the belt thickener and then into the chamber filter press. Dewatered sludge with a moisture content of 75% is transported by trucks to the solid waste landfills. The implementation of these innovations provided for the significant reduction of water amount used for own needs; thus, the total water losses do not exceed 1.5%; water abstraction from the water source was also reduced as well as the water supply deficit. The results of the first several months of the ultrafiltration facilities operation showed that the quality of the treated drinking water met the requirements of the sanitary regulation and standards.

Key words

ultrafiltration , filter washings reuse , sludge treatment , water supply deficit