LAUSR

Abstract Nitrate (NO3−) loads from domestic and industrial wastewater contribute to surface and groundwater pollution and can have detrimental effects on human health and the environment. In this study, a particulate pyrite autotrophic denitrification (PPAD) process was compared with sulfur-oxidizing denitrification (SOD) in batch microcosms using a domestic wastewater seed. During a 65-day acclimation period, denitrification rates for PPAD reached 3.19 mg/(L·d), but were slower than the maximum rate for SOD (∼5 mg/[L·d]). Lower sulfate (SO42−) production (5.66 mg SO42−/mg NO3−-N) and alkalinity consumption (1.70 mg CaCO3/mg NO3−-N) were observed with PPAD than with SOD (7.54 mg SO42−/mg NO3−-N and 4.57 mg CaCO3/mg NO3−-N). Acetone pretreatment of pyrite particles initially resulted in a transient increase in the denitrification rate; however, the rate of denitrification was similar to untreated pyrite in subsequent cycles. Box–Behnken design and response surface methodology were used to optimize biomass ...