Environmental and energy efficiency of a selected municipal wastewater treatment plant - a case study

Based on the analysis of environmental and energy efficiency in the years 2019-2021 in the selected sewage treatment plant (WWT) located in the southern Poland with mechanical-biological wastewater treatment, it was found that the highest level of pollution reduction of 98% enabled the highest BOD5 concentration to be reduced more than 800 times. The operation of the sewage treatment plant was characterized by variable efficiency of the treatment process, which was demonstrated by significant differences in chemical indicators (BOD5, COD, P, TSS and N). Low average concentration of total nitrogen below 4 mg l-1 occurred with a reduction of pollutants at a level not exceeding 90%. Noticeable energy consumption of 1.58 kWh m-3 related to the increase in the amount of treated sewage, confirmed by a moderate correlation, indicated the need to optimize the treatment process.