The role of colloidal and particulate organic compounds in denitrification and EBPR occurring in a full-scale activated sludge system

摘要

The efficiencies of denitrification and enhanced biological phosphorus removal (EBPR) in biologicalnnutrient removal (BNR) activated sludge systems are strongly dependent on the availability ofnappropriate carbon sources. Due to high costs of commercial compounds (such as methanol,nethanol, acetic acid etc.) and acclimation periods (usually) required, the effective use of internalncarbon sources for denitrification is preferred. The aim of this study was to determine thenimmediate effects of slowly biodegradable substrates on the denitrification capability andnphosphate release/uptake interactions for a full-scale biomass process from the ‘‘Wschod’’nwastewater treatment plant (WWTP) in Gdansk (Poland). Since it is hard to distinguish the slowlynbiodegradable substrate in a direct way, a novel procedure based on batch experiments wasndeveloped and implemented. The laboratory experiments were carried out in two parallel, fullynautomatic batch reactors with the settled wastewater without pretreatment and after coagulationflocculation.nThe removal of colloidal and particulate fractions resulted in the reduced observednprocess rates, such as denitrification, phosphate release and phosphate uptake (under aerobicnand anoxic conditions). The reduction ranged from approximately 14% for the anaerobic P releasento approximately 46% for the anoxic P uptake.