Design of a bioaugmented soil aquifer treatment for efficient removal of p-nitrophenol

Secondary effluent reclamation and reuse is an effective solution to the water shortage problem, and the safety of reused water is a matter of increasing concern. p-Nitrophenol (PNP), a common secondary effluent pollutant, can be efficiently removed using the eco-friendly bioaugmented soil aquifer treatment (SAT) system at the laboratory scale. In this study, a sewage treatment plant in Changchun was selected as a case study to apply the bioaugmented SAT system for field scenarios efficiently. The bioaugmented SAT system was simulated using HYDRUS-1D code. Biodegradation and adsorption coefficient were conducted from the batch experiment. Based on the degradation experiments, the concentration of bacteria injected into SAT system was designed to be 6 x 10(18) colony-forming units (CFU) m(-3). To enhance the efficiency of the bioaugmented SAT system, the key parameters were optimized based on the sensitivity analysis and the response surface methodology, which showed that the optimal operating conditions were an initial concentration of 86.11 mg L-1, a medium of 4.27-m thickness, and a wet/dry ratio of 0.28. Specifically, alternated wetting-drying conditions and increasing the medium thickness reduced PNP within a specific range. This work demonstrates the performance and applicability of the bioaugmented SAT system for removal PNP in secondary sewage effluent.