The microbiome of two strategies for ammonia removal with the sequencing batch moving bed biofilm reactor treating cheese production wastewater

Abstract

ABSTRACT The moving bed biofilm reactor is a compact technology established for treating total ammonia nitrogen (TAN) from municipal wastewater via nitrification or denitrification. The sequencing batch moving bed biofilm reactor (SB-MBBR) has been applied for on-site biological treatment of carbon and phosphorous from cheese production wastewater; however, nitrification is limited by the competition between nitrifiers and heterotrophs. Two strategies are compared to circumvent heterotrophic competition and achieve TAN oxidation in an SB-MBBR system already achieving carbon and phosphorous removal: extended aerobic operation of a single SB-MBBR and two SB-MBBRs in series. TAN oxidation occurred after 810 hours with the extended aerobic operation, where a microbiome shift occurred to support an ammonia-oxidizing bacterial population. Thus, a single SB-MBBR is not feasible for achieving nitrification simultaneously with carbon and phosphorous removal when treating cheese production wastewater. After 30 hours of operation, two SB-MBBRs in series achieve TAN removal, possibly through partial nitritation, with a TAN surface area removal rate of 1.07 ± 0.05 g-N·m −2 d −1 and an enriched abundance of ammonia-oxidizing bacteria. To the best of our knowledge, this is the first study to analyze the microbiome of the SB-MBBR achieving TAN removal from cheese production wastewater and present an operational strategy to achieve TAN while treating cheese production wastewater with SB-MBBRs. Also, this is the first study to show evidence that partial nitrification can be achieved in an SB-MBBR system that is also treating carbon and phosphorous from cheese production wastewater and demonstrates the potential for the SB-MBBR to be incorporated in a deammonification system. IMPORTANCE Cheese production facilities must abide by sewage discharge bylaws that prevent overloading municipal water resource recovery facilities, eutrophication, and toxicity to aquatic life. Compact treatment systems can permit on-site treatment of cheese production wastewater; however, competition between heterotrophs and nitrifiers impedes the implementation of the sequencing batch moving bed biofilm reactor (SB-MBBR) for nitrification from high-carbon wastewaters. This study demonstrates that a single SB-MBBR is not feasible for nitrification when operated with anerobic and aerobic cycling for carbon and phosphorous removal from cheese production wastewater, as nitrification does not occur in a single reactor. Thus, two reactors in series are recommended to achieve nitrification from cheese production wastewater in SB-MBBRs. These findings can be applied to pilot and full-scale SB-MBBR operations. By demonstrating the potential to implement partial nitrification in the SB-MBBR system, this study presents the possibility of implementing partial nitrification in the SB-MBBR, resulting in the potential for more sustainable treatment of nitrogen from cheese production wastewater.