Unveiling the effects of soluble starch, ethanol, and sodium acetate on the interactions of functional microorganisms and nitrogen removal in a partial nitritation and anammox biofilm system

Different organic matters have different effects on the nitrogen removal performance of partial nitritation and anammox (PN/A) biofilm system. In this study, the effects of adding soluble starch, ethanol, and sodium acetate on the functional microorganisms and nitrogen removal in the PN/A biofilm system are investigated. The results show that ethanol had the strongest effects on the ammonium-oxidizing bacteria (AOB) growth, enrichment, and ammonium nitrogen removal rate, followed by soluble starch and sodium acetate. However, the suppression of anaerobic ammonium oxidation bacteria (AnAOB) and decrease in total nitrogen removal rate were affected the most by ethanol, followed by soluble starch and sodium acetate. In addition, the enrichment of nitrifying oxidizing bacteria (NOB) was the most strongly influenced by ethanol, followed by soluble starch and sodium acetate. Furthermore, the enrichment of phylum Proteobacteria was facilitated by ethanol > soluble starch > sodium acetate. The enrichment of phylum Nitrospirae and genus Nitrospira were influenced by ethanol > soluble starch > sodium acetate. However, the suppression of the phylum Planctomycetes and the genus Candidatus Brocadia were affected by ethanol > soluble starch > sodium acetate. These results show that the PN/A biofilm system is suitable for the treatment of ammonium nitrogen wastewaters containing organic salt (sodium acetate) but not for treating wastewaters containing organic alcohol (ethanol) and macromolecular organic matter (soluble starch).

Automated summary

This study investigates the effects of adding soluble starch, ethanol, and sodium acetate on the microorganisms and nitrogen removal in the PN/A biofilm system. The results show that ethanol has the strongest effects on AOB growth and ammonium nitrogen removal rate, followed by soluble starch and sodium acetate. However, ethanol also has the most significant impact on the suppression of AnAOB and total nitrogen removal rate. Furthermore, ethanol has the greatest influence on the enrichment of NOB and certain bacterial phyla.