Обґрунтування доцільності впровадження усереднювачів в технологію очистки господарсько-побутових стічних вод

Abstract

The inflows of municipal sewages discharged to wastewater treatment plants for full biological treatment can vary widely throughout the day. Therefore, one of the ways of optimizing the operation of wastewater treatment plants is the use of regulating tanks – equalization basins, providing the possibility of uniform supply of wastewater with averaged concentration. The purpose of the paper is to substantiate the feasibility of using equalization basins in the technological cycle of complete biological treatment of household wastewaters. According to the analysis of technological data of the Livoberezhnna Aeration Station (LAS) located in Dnipro City the sewage inflow rates at treatment plant have significant daily variations. In this regard, there is a need to implement a separate technological operation to equalize the water inflow before the primary sedimentation tanks and aeration tanks in order to normalize the flow and average concentration of pollutants. On the basis of the initial data of qualitative and quantitative indicators of water samples chemical analysis the load of biochemical oxygen demand (BOD) at the treatment plant was calculated. The volume of the equalization basin is determined according to the methodology widely used in American universities and engineering companies in the USA. The results of calculations of wastewater averaging according to BOD indicate the effect of equalization of pollutant concentrations during the day. Thus, the ratios of BOD load values for wastewater treatment without equalization and with equalization basins are: maximum to minimum — 25,82 and 2,05; minimum to average — 0,08 and 0,62; maximum to average — 2,06 and 1,27 respectively. It is established that the average wastewater outflow in the volume of 0,307 m3/s allows avoid overloading by BOD concentrations, in contrast to the actual inflow, the volume of which can fluctuate during the day.