LAUSR

This paper presents analyses of the percentage shares of organic pollutants fractions expressed as chemical oxygen demand in domestic wastewater, treated in individual systems. Wastewater from nine facilities, consisting of a primary settling tank and a biological reactor with activated sludge, or from a primary settling tank and a reed bed with a purification pond were examined within this study. The dissolved and suspended readily biodegradable fraction was found to be dominant (about 80%) in the effluent leaving the primary settling tank at a relatively high portion of the suspended biodegradable fraction in biologically treated wastewater (about 25%–51%). The tested wastewater was assessed as biodegradable. It was found that the differences in the composition of sewage from individual and municipal sewage treatment plants result from the diversity of sewage sources and the specific operation of the equipment.