文摘
A control system with the objective of improving nitrogen removal has been installed in a 60,000 p.e. communal wastewater treatment plant. The system controls the biological stage of the activated sludge plant employing mass balances for evaluating the control measures. The control resulted in an overall reduction of the nitrogen output by half and one third in warm and cold periods respectively, compared to an uncontrolled reference train. Violating effluent standards could be avoided through the application of the control system.