ACASE STUDY ON THE SLUDGE CHARACTERISTICS IN BIOLOGICAL NUTRIENT REMOVAL PILOT PLANT AT THE SJÖLUNDA WASTEWATER TREATMENT PLANT IN MALMÖ
It has been found in several studies that the sludge settleability may deteriorate when a biologicai nutrient removal process is applied. However, so far only a few studies on the sludge characteristics at Swedish wastewater treatment plants with biological nutrient removal have been reported. A rwo-year study (august 1991-july 1993) at the Sjölunda wastewater treatment plant was therefore perfonned in a pilot plant, operated in three different modes, with the aim to follow the sludge characteristics in a nutrient removal process. It was found that as the pilot plant was operated at low effluent concemrations of phosphorus and nitrogen (0.5 mg P/l, 8 mg N/l), i.e. 20 days sludge age and high recirculation, the diluted sludge volume index (DSVI) increased significantly to 150 ml/g. The DSVI then fluctuated around 125-150 ml/g for the; fist of the investigated period. Microscopical investigations showed that the change of DSVI corresponded to a similar change in the amount of filamentous bacteria determined as the filament index.
“Complete abstract not presented.”