Evaluation of air pollutants emitted from wastewater treatment processes in Egypt

Abstract

AbstractDespite the importance of wastewater treatment plants (WWTPs) to decontaminate wastewater, and consequently relieving the global freshwater reserves of industrial and domestic pollution, their effect on the air quality of the surrounding areas is often overlooked. The main aim of this work was thus to evaluate the nature and levels of common air pollutants released from different operating processes of a major WWTP in Egypt (Abu‐Rawash WWTP). Concentrations of gaseous pollutants (CO, NO2, SO2, NH3, H2S, total volatile organic compounds) and particulate matter (PM2.5, PM10, and total suspended particulates) at each of the wastewater treatment operation processes within the premises were measured from September to December 2019. The intercorrelations between all pollutants were examined by principal component analysis using Minitab 17 statistical software. The results showed that the highest emission rates of gaseous pollutants were derived from the sludge thickening and dewatering process, and from the sedimentation tanks, whereas the highest levels of particulate matter were detected at the sludge handling facilities and cyclone devices. However, the recorded levels were generally lower than the maximum threshold limits set by the Egyptian Environment Laws (Law 4 of 1994 for the Protection of the Environment amended by Law 9/2009, and Law 105/2015) and the European Commission air quality guideline. This study emphasizes that the environmental impacts resulting from the direct air emissions of gases and particulates should be closely monitored if wastewater facilities are located in the vicinity of residential areas.