Effects of Perfluorooctanoic Acid on River Sediment Denitrification and Remediation by Sulfur Autotrophic Denitrification-Anammox Coupled Microbial Consortia.

This study explored the effects of perfluorooctanoic acid (PFOA) on river sediment denitrification and its remediation using a coupled sulfur autotrophic denitrifying-Anammox microbial consortia. River sediments possessed intrinsic denitrification potential. However, PFOA did not inhibit ammonia nitrogen removal but accelerated nitrite oxidation, causing nitrate accumulation, altering the contents of extracellular polymeric substances and soluble microbial products, inhibiting heme-c secretion, and elevating nitrite reductase activity (0.22-0.93 ng nitrite/(min·mg protein)). After microbial enhancement, sediment PFOA tolerance and denitrification improved (initial ammonia removal rate was 0.247 mg/(g·day)), while heme-c secretion remained unaffected and nitrite reductase elevation showed PFOA concentration dependence. PFOA reduced the abundance of Proteobacteria and Sulfithrix in native sediments, whereas microbially enhanced communities exhibited higher stability. Enrichment of functional genes (hzsB, amoA) enhanced denitrification and stress resistance, providing insights and technical support for PFOA-contaminated sediment bioremediation.