Experimental research of combined horizontal settling tank for drinking watersupply

Abstract

Abstract Nowadays, the war in Ukraine brings not only material and human losses, but also significant environmental damage. The full-scale Russian invasion of Ukraine led to serious environmental consequences for the country’s northern, southern and eastern regions. Water treatment from surface sources occurs according to various technological schemes. Still, the most common scheme for water treatment plant with productivity of 30,000 m3/day or more is a two-stage scheme with a horizontal settling tank in the first stage and rapid sand filters in the second stage. Disadvantages of horizontal settling tank are uneven water distribution across the sump, longitudinal circulation, an insufficiently efficient drainage system for clarified water, and unsatisfactory operation at low temperatures. To intensify the operation of horizontal settling tanks, we proposed next solution: to place thin-layer continuous settlers with countercurrent water movement at the beginning of the sedimentation zone. Such an arrangement makes it possible to retain suspended particles at the facility’s beginning, reduce the mud load on the horizontal settler and increase the water velocity in thin-layer settlers. This research aims to intensify the operation of horizontal settling tanks and improve the quality of water clarification. Experimental studies of the combined horizontal settling tank design were conducted. It shows the efficiency of its work, improving the quality of water treatment.