The waste water treatment plant to be analysed was built in 1998 and installed in the existing liquid manure storage pit (two rows; see picture). The purpose is the treatment of wastewater from dairy and slaughterhouse. The system works in just two steps, a primary activated sludge basin (ASB) and a secondary settler. The intermitting aeration in the ASB serves for carbon degradation and nitrification, as well. The daily load is in the range of 50 m³ and transported through the WWTP only by daytime. The current effects are an insufficient CSB reduction as well as increased nitrate and phosphate values.
Aim of this study is to figure out the cause of insufficient performance of a wastewater treatment plant. Therefore, a complete mass balance has to be done and the results have to be discussed with respect to organic/nitrogen load, biomass availability and retention time.