Validation of effective role of substrate concentrations on elemental sulfur generation in simultaneous sulfide and nitrate removal process

Abstract

Simultaneous nitrogen and sulfur removal process has broad application prospects, which can accomplish simultaneous sulfide and nitrate removal to recover elemental sulfur from wastewater. The effective role of substrate concentrations in elemental sulfur generation was investigated through substrate removal, product conversion, characteristics and distribution of elemental sulfur along microbial community structure. Furthermore, a multivariate linear fitting equation was used to simulate the contribution of substrate concentration on elemental sulfur generation. Based on the statistical analysis (Multiple comparisons, Pearson correlation analysis and Principal Component Analysis), it was confirmed that substrate concentration elevation exerted a significant positive effect on the generation of elemental sulfur regardless of its presence in either effluent or sludge (p < 0.05). The results showed that bulk of the produced elemental sulfur mainly existed in the effluent of the reactor (76.59–88.28% of total elemental sulfur), rather than in the sludge (11.72–23.41% of total elemental sulfur). Zeta potential of elemental sulfur in the effluent was in the range of −15.70 mV to −18.92 mV. Sulfurovum was the dominant genus enriched by high substrate concentration whose relative abundance was higher than 79.46%.