Design and construction of wastewater treatment facilities for small sewerage facilities

Abstract

The study investigated the effectiveness of clarification of domestic wastewater of small sewerage facilities in the suspended bed of activated sludge. The research was conducted in semi-production and production conditions on the example of a small sewerage facility of East Kazakhstan region with discharge into the river Yertis. The purpose of the study is to develop an effective scheme of wastewater treatment for small sewerage facilities. The experimental method was used to study the effectiveness of water clarification. Analytical, systematic, comparative methods, as well as methods of mathematical statistics were used to process the experimental results. The results showed the effectiveness of wastewater treatment in suspended bed of activated sludge flakes sludge. The obtained treatment effect in semi-production and production conditions is comparable with the effect of additional wastewater treatment on sand filters. The treatment effect in semi-production conditions for suspended solids was in the range from 87.5 % to 92 %, and for BOD5 in the range from 70 % to 72 %. For the application of this technology in production conditions, it was found that the optimal height of suspended bed from 2 to 2.5 m, and the speed of upward water flow from 0.2 to 0.7mm/sec. At the same time, the residual concentration of suspended solids is in the range of 5–10 mg/l. Treatment with the use of aeration zones and suspended bed of activated sludge can be used for effective clarification of domestic wastewater of small sewerage facilities.