Energieffektiviserad luftning på Sternö avloppsreningsverk / Energy improved aeration at Sternö Wastewater Treatment Plant
The objective of this study was to improve the aeration efficiency of a mid-size Swedish wastewater treatment plant in full-scale trials. The full-scale trials were performed at Sternö wastewater treatment plant, which was built in 1997 and is designed for 26,000 population equivalents. The biological treatment at Sternö wastewater treatment plant is performed in two separate treatment lines, of which one line served as a reference line with intact aeration equipment and the other one as a test line. The reference line was equipped with conventional lobe blowers, tube diffusers and simple dissolved oxygen control installed during the construction of the plant. The test line was equipped with its own aeration equipment. When evaluating the energy efficiency, the reduction of BOD and of ammonium, and the excess oxygen concentration were considered. The results show that 64 % of the aeration energy can be saved when implementing an Atlas Copco ZS 45+ VSD blower, Sanitaire Silver Series Low Pressure diffusers and Sanitaire Advanced Process Control system. These results are based on 29 weeks of continuous measurements. The savings in the test line correspond to 14 % of the total energy consumption of the plant and the payback time for the installed aeration equipment is four years. The energy savings were performed with improved effluent quality.