Pyrite and PHBV Combined as Substrates for Groundwater Denitrification

Facing the growing threat of nitrate contamination in groundwater, this study presents an innovative approach to in-situ denitrification using a novel combination of pyrite and polyhydroxybutyrate-co-valerate (PHBV) as solid-phase electron donors. By evaluating two mass ratios (1:1 and 1:2) of PHBV to pyrite in lab-scale permeable reactive barrier systems, the research reveals high nitrate removal efficiencies of up to 97.65%, with minimal dissolved organic carbon in the effluent. Microbial analysis indicates that pyrite content significantly influences microbial community structure and functional gene expression, with the 1:2 ratio favoring aerobic denitrifiers and a broader functional gene profile. The findings highlight a promising, cost-effective mixtrophic denitrification strategy for sustainable groundwater remediation.