| Summary: | Munitions in industrial wastewater is an emerging area of concern with few efficient and economical treatment options. Membrane separation technologies could minimize munitions wastewater volumes, but have not been fully investigated. Herein, a response surface model (RSM) is used to investigate flux and munition rejections from simulated wastewater as a function of pH, transmembrane pressure, and co- and counterion concentrations. Rejection of 3-nitro-1,2,4-triazol-5-one (NTO), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4-dinitroanisole (DNAN) and nitroguanidine (NQ) is determined for reverse osmosis (RO) membranes, namely BW30 and SW30XLE. Rejection using reverse osmosis is between 97.5% and 99.9% for NTO, 89.9%–99.4% for RDX, 96.1%–98.8% for DNAN, and 80.4%–96.2% for NQ. The RO membrane rejection is stable over 4 or more cycles with munitions spiked domestic wastewater and flux is rapidly regained after regeneration with 0.05% NaOH. Flux and performance index are twice as high for the BW30 membrane compared to the SW30XLE membrane. Operational costs for RO of munitions wastewater are 0.138 USD/m3 assuming 0.07 USD/kWh and fluxes of 0.68 ± 0.21 m3/m2/day. Gaussian process models are preferred for modeling the effect of pH, ionic concentration and pressure on membrane performance. Results herein suggest that reverse osmosis should be considered in munitions wastewater treatment trains.
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