Increased influent RBCOD and heterotrophic plate counts coincided with the start of bioaugmentation in this study. Observed influent sulfide levels were also lower duringbioaugmentation. 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.
Microorganisms were continuously added to the sewer collection system in order to engineer a biological change in the sewer biofilm and biological populations, for a full-scale 5 stage BardenphoTM Biological Nutrient Removal (BNR) wastewater treatment plant. Data was collected for 1 year prior to implementation of the technology, 9 months during implementation, and 2 months following cessation of the technology. The biological product is a proprietary blend of bacteria so no information about its’ composition is known by the major author, including what electron acceptors or electron donors may be included, or what predominant metabolic pathways are provided from gene expression of the added bacteria.