DEMONSTRATION OF INTEGRATED FIXED FILM ACTIVATED SLUDGE PROCESS FOR BNR AT THE MAMARONECK WWTP

This paper presents the significant results and interim conclusions of a full-scale demonstration project at the Mamaroneck Wastewater Treatment Plant (WWTP) on the application of an integrated fixed film activated sludge (IFAS) system using flexible strand media. Concurrent operation of the Modified Ludzack-Ettinger (MLE) activated sludge process without IFAS media was also undertaken to act as a control. The purpose of the Demonstration Project is to determine if the total nitrogen discharge requirements of the Long Island Sound Study can be achieved year-round with limited new construction and nominal cost via operation and process control modifications.The MLE process performed well in terms of nitrification/denitrification and can be further optimized in terms of dissolved oxygen control, methanol feed, solids inventory control and floating sludge (“froth”) control on the final settling tanks.The IFAS media did not improve the nitrogen removal capacity of the MLE process on a sustained basis, with two incidents of predatory red worm infestations hindering nitrification. Very limited process benefits associated with the media were observed in terms of higher denitrification rates and better sludge settling. Notwithstanding, these were not accompanied by an enhancement of overall nitrogen removal beyond other modifications made for the demonstration of biological nutrient removal at the Mamaroneck WWTP.