Pollution based real time control strategies for combined sewer systems

This paper presents results from an application of a newly developed simulation tool for pollution based real time control (PBRTC) of urban drainage systems. The Oslo interceptor tunnel is used as a case study. The paper focuses on the reduction of total phosphorus P_tot and ammonia-nitrogen NH₄-N overflow loads into the receiving waters by means of optimized operation of the tunnel system. With PBRTC the total reduction of the P_tot load is 48% and of the NH₄-N load 51%. Compared to the volume based RTC scenario the reductions are 11% and 15%, respectively. These further reductions could be achieved with a relatively simple extension of the operation strategy.