Efficiency assessment of wastewater treatment plants: A data envelopment analysis approach integrating technical, economic, and environmental issues

Analysis and Assesment of the Wastewater Treatment Plant Operation in the City of Kłodzko

“…The highest value of this indicator in the wastewater flowing into the WWTP was observed in the IV quarter of 2015 and amounted to 1227.90 mg•dm -3 , whereas in the treated sewage, the highest concentration of TSS was noted in the I quarter of the same year (23.25 mg•dm -3 ) and it was lower than the permissible value by approximately 34%. Comparing the fluctuations of the concentration of total suspended solids with the charts for BOD 5 and COD Cr , a similar trend was observed in the increase of these parameters in raw sewage at the turn of 2015/2016. Moreover, the correlation between the changes in the concentration of BOD 5 and TSS in the sewage entering the treatment plant should be noted.…”

“…Comparing the fluctuations of the concentration of total suspended solids with the charts for BOD 5 and COD Cr , a similar trend was observed in the increase of these parameters in raw sewage at the turn of 2015/2016. Moreover, the correlation between the changes in the concentration of BOD 5 and TSS in the sewage entering the treatment plant should be noted. This correlation indicates the participation of large amounts of biodegradable particles which affect increase in the value of the biochemical oxygen demand in whole volume of suspended solids.…”

“…The sand collected in sludge concentrator is directed to the process of dewatering and then also transported to the compost pile. The next element is the primary settling tank, which removes 60-70% of the total suspended solids and about 30% of BOD 5 . The sludge created in the primary settling tank is subjected to an acid fermentation and constitutes a source of volatile fatty acids for the Enhanced Biological Phosphorus Removal (EBPR) process [Randall et al 1998].…”

“…Thus, the protection of its resources is a serious challenge for the scientists, technologists and engineers. As emphasized by the Water Framework Directive, the issues related to rational and efficient water and wastewater management should be multidisciplinary [Arnell 2016, Castellet & Molinos-Senante 2016. World Health Organization (WHO) estimates, that up to 80% of illnesses and infections in the world result from inadequate treatment of sewage and thus insufficient amount of clean water.…”

“…The choice of the appropriate sewage treatment method requires the quantitative and qualitative analysis of influent wastewater, the effectiveness of the adopted technology and the economic aspects [Arnell 2016, Castellet & Molinos-Senante 2016, Łagożny et al 2015, Bugajski 2014. Improper selection of the technology and dimensions of the treatment plant can result in subsequent high operating costs, inadequate efficiency of wastewater treatment and thus, the failure to meet the requirements of the water permit which entails the financial penalties imposed on the wastewater treatment facilities [Młyński et al 2016b].…”