Dynamic loading tests for final settling tanks

Abstract

Dynamic experiments conducted in a pilot scale settling tank at Zurich's wastewater treatment plant (WWTP) are presented. The experiments were carried out with real activated sludge. They showed that vertical perforated walls transverse to the main flow direction are very beneficial particularly for wet-weather flow. The increase of the effluent suspended solids concentration is significantly dampened with dynamic hydraulic loading. Installing several perforated walls enables uniform velocity profiles to be attained, enhancing flocculation. The total sludge mass stored in the final settling tank may be increased by this system and requires special attention when the removal system is designed.