Both Nitrate Reduction and Sulfate Reduction Were Occurring as Bioremediation Mechanisms

This modification of enhanced anaerobic bioremediation uses non-activated persulfate to accelerate the breakdown of organic phosphorus. It then stimulates benzene biodegradation by nitrate and sulfate reduction. This novel modification of enhanced anaerobic bioremediation techniques uses non-activated persulfate to accelerate the organic phosphorus breakdown, and then stimulate benzene biodegradation by nitrate and sulfate reduction. Benzene concentrations in groundwater where nitrate, triethyl phosphate, and persulfate were successfully injected were reduced at removal efficiencies greater than 77% to levels below the applicable guidelines. Soil benzene was removed effectively by modification of enhanced anaerobic bioremediation, with removal efficiencies ranging between 75.9% and 92.8%. Geochemical analytical results indicated that persulfate effectively breaks down triethyl phosphate into orthophosphate, promoting nitrate and sulfate utilisation. Microbial analyses demonstrated that benzene was primarily biodegraded by nitrate reduction, while sulfate reduction played an important role in benzene removal in some parts of the study site. Enrichment in the heavier carbon isotope 13C of residual benzene with increased removal efficiency provided direct evidence for benzene biodegradation. Nitrogen, sulfur, and oxygen isotope analyses indicated that both nitrate reduction and sulfate reduction were occurring as bioremediation mechanisms. Source: filtsep