Impact of instrumentation reliability on mainstream suspended Partial denitrification anammox (PdNA).

Abstract

This study successfully revealed the importance of probe reliability and sensitivity with ion sensitive electrode (ISE) probes on achieving high partial denitrification (PdN) efficiency; and decreasing carbon overdosing events that cause the decline of microbial populations and performance of partial denitrification-anammox (PdNA). In a mainstream integrated hybrid granule-floc system, an average PdN efficiency of 76% was achieved with acetate as the carbon source. Thauera was identified as the dominant PdN species; Its presence in the system was analogous to instrumentation reliability and PdN selection and wasn't a consequence of bioaugmentation. Up to 27-121 mg TIN/L/d, an equivalent of 18 - 48% of the overall TIN removed, was achieved through the PdNA pathway. Candidatus Brocadia was the main anoxic ammonium oxidizing bacteria (AnAOB) species that was seeded from sidestream, and enriched and retained in the mainstream system with observed growth rates of 0.04 - 0.13 d-1 . Moreover, there was no direct negative impact of methanol's use for post-polishing on AnAOB activity and growth.