Effects of polycyclic aromatic hydrocarbons on sludge performance for denitrification and phosphorus removal

Abstract

To study the long-term effects of polycyclic aromatic hydrocarbons (PAHs) on traditional denitrification and phosphorus removal process, different concentrations of PAHs (naphthalene NAP, phenanthrene PHE) were added into two sequencing batch reactors. Experimental results demonstrated that NAP and PHE had a positive influence on denitrification performance and that the total nitrogen efficiency was 79.59%, with effluent less than 15 mg/L. However, phosphorus removal performance began to deteriorate with 0.1 mg NAP/L and 0.2 mg PHE/L. Microbial community analysis revealed that phosphorus accumulating organisms were enriched in the NAP system (40.15%) compared to the PHE and blank test (15.75%, 19.45%), which led to a reduction in PO43−-P efficiency from 98.25% to 83.33% and 96.77% to 87.50%, respectively. Shinella and Parcubacteria were found to contribute to NAP and PHE degradation.