Technological reliability of sewage treatment plant with the Pomiltek Mann type bioreactor

The aim of the work was to determine the technological reliability of the selected pollution indicators removal BOD₅, COD_Cr and total suspension from the sewage treatment plant working with the bioreactor Pomiltek Mann type. Wastewater treatment plant which is a subject of this study is located in Lesser Poland, in Siepraw commune. The analysis was performed using the Weibull method for basic indicators of impurities, BOD₅, COD_Cr and total suspended solids. Physico-chemical analyses of raw and treated wastewater, were carried out in the period from 2003 to 2014 (11 years). The research period included measured values of pollutions indicators in 38 samples of raw and treated sewage. For each of pollution indicators descriptive statistic, percentage reduction (n) and treatment plant reliability factors (RF) were calculated. Average reduction for BOD₅ and TSS was on level equal 94%, only for COD the average reduction was lower and was on level 89%. The reliability values determined by Weibull method, were: 75% (BOD₅), 90% (COD_Cr) and 89.5% (TSS). The reliability results have been lower than the presented by literature source, which means that work of wastewater treatment plant in Siepraw was not satisfied in 11 years of research.