Biologically Engineered Biofilm Modifications for the Enhancement of Collection System Transformations and Impacts on BNR Wastewater Treatment

Increased influent RBCOD and heterotrophic plate counts coincided with the start of bioaugmentation in this study. Observed influent sulfide levels were also lower during bioaugmentation. RBCOD increases could potentially improve biological phosphorus or nitrogen removal. Lowered sulfides in the influent could lower corrosion and odors in the collection system and preliminary treatment/plant headworks.The effects of nitrification inhibitor on influent BOD values was also investigated. CBODs were significantly lower than BODs for both influent and anaerobic zone BOD. This was true for both filtered and unfiltered (soluble) samples. The difference between BOD and CBOD increased during the summer months, and in addition nitrifiers were measured in influent BOD bottles not containing inhibitor. It seems likely that the reasons for the difference between influent BOD and CBOD was at least partially due to nitrification. In addition inhibition of BOD degradation by the nitrification inhibitor may also play a role. Albertsons (1995) hypothesis that the difference between influent BOD and CBOD is due to inhibited degradation of particulate BOD seems unlikely since soluble CBOD/BOD ratios were similar to values and trends observed for total CBOD/BOD ratios.