Heavy metals in domestic wastewater with respect to urban population in Ostrava, Czech Republic

Abstract

During dry weather periods, domestic wastewater is a major component of urban wastewater influent to a wastewater treatment plant (WWTP). For this reason, the quantity and quality of domestic wastewater have a considerable effect on the resultant contamination of urban wastewater and on the subsequent selection of appropriate WWTP technology. The aim of this study was to quantify the amount of hazardous elements in domestic wastewater to determine the average daily production of domestic wastewater and risk elements per inhabitant and quantify the proportion of households in the total load of urban wastewater. Wastewater samples were collected from nine local sewer systems in Ostrava, the Kravare WWTP and the Central Wastewater Treatment Plant of Ostrava (Czech Republic). We found that the average production of wastewater from households is approximately 135 L per person per day. The results also show that the share of households in urban wastewater is approximately 60% in the case of Cd, 35-21% in the case of Zn, Cu, As and less than 15% for Pb, Cr, Fe, Ni and Mn.