Effect of Organic Matter on the Nitrogen Removal Through Sulfate Reducing Anaerobic Ammonia Oxidation Process: A Comparative Study on Inorganic and Organic Conditions

Abstract

Sulfate reducing anaerobic ammonium oxidation (S-Anammox) is a novel biological process that involves the oxidation of NH4+ coupled with the reduction of SO42-. This study conducted a thorough comparative analysis to assess the influence of inorganic versus organic conditions on S-Anammox. The results demonstrated that the inorganic treatment exhibited a higher NH4+-N removal rate and activity (0.15 kgN/(m3 d) and 1.10 mgN/(gVSS h)) compared to the organic treatment (0.04 kgN/(m3 d) and 0.34 mgN/(gVSS h)). More sulfate was removed in the organic treatment, leading to the retention of elemental sulfur in the sludge (S0 0.8% to 6.0%). qPCR analysis revealed that organic matter inhibited the abundances of key genes involved in ammonia oxidation (amoA and hao) and sulfide oxidation (soxB). High-throughput sequencing of functional genes dsrAB and soxB revealed distinct populations of specific sulfate reducing bacteria (SRB) and sulfur oxidation bacteria (SOB) under organic and inorganic conditions.

Keywords: Sulfate reducing anaerobic ammonium oxidation, Nitrogen removal, sulfur cycle, High-throughput sequencing, Functional bacteria