Study of a combined sulfur autotrophic with proton-exchange membrane electrodialytic denitrification technology: Sulfate control and pH balance

Electric Power Consumption and Current Efficiency of Electrochemical and Electrobiological Rotating Disk Contactors Removing Nutrients from Wastewater Generated in Soil-Less Plant Cultivation Systems

“…Prosnansky and Sakakibara [11] concluded that once these two parameters are wrongly adjusted they decrease CE value due to the loss of generated nitrogen, because they fail to ensure the sufficient contact time between the substrate and the biomass and cause pH increase above the optimal value. In the present study, the highest CE value, reaching 80.2%, was achieved at the lowest electric current density of 0.63 A/m 2 and the shortest hydraulic retention time of 4 h. This CE is comparable with values reported by Wan et al [12], i.e., from 68.0% to 77.0%. In turn, Feng et al [20] achieved the current efficiency of 32.0% ± 0.5% in their experiment conducted in a bioelectrochemical system (BES) with sodium bicarbonate (NaHCO 3 ) as a carbon source.…”

“…Due to the loss of generated hydrogen, they failed to ensure the sufficient contact time between the substrate and the biomass and caused pH to increase above the optimal value [11]. A study conducted by Wan et al [12] demonstrated that the optimal current efficiency (in the function of HRT) ranged from 68% to 77% and also that more than 68% of the generated H2 was consumed by hydrogenotrophic bacteria. In turn, Ghafari et al [13], who treated water containing 20 mg N/L, showed the effective HRT to range from 13.5 to 30 h, and current density from 10 to 16 mA.…”

An integrated process of three-dimensional biofilm-electrode with sulfur autotrophic denitrification (3DBER-SAD) for wastewater reclamation

“…Reactions (5), (6) and (7) are theoretical equations for denitrification by heterotrophic, hydrogenotrophic and sulfur autotrophic denitrifying bacteria using organic carbon source CH 3 COONa, H 2 and S 0 as the electron donor, respectively. The H + generated by sulfur autotrophic denitrification as shown in reaction (7) can promote the proceeding of reaction (3) (Wang and Qu 2003;Wan et al 2011), and the produced H 2 gas can then serve as the electron donor for further hydrogenotrophic denitrification as described in reaction (6).…”

“…They found that the H + produced in the sulfur denitrification part could be consumed by hydrogen denitrification in the BER part, and the effluent from two parts was kept neutral at optimum operation conditions (Wang and Qu 2003). Wan et al (2011) used a system consisting of a BER denitrification reactor based on proton-exchange membrane electrodialysis and a sulfur autotrophic denitrification column, and they observed a 95.8 % NO 3 − −N removal without NO 2 − −N accumulation and an effluent SO 4 2− concentration of 202.1 mg/L. However, the previous studies of coupled denitrification reported the separation of sulfur autotrophic denitrification process from the BER process (Wang and Qu 2003;Wan et al 2011).…”

“…Wan et al (2011) used a system consisting of a BER denitrification reactor based on proton-exchange membrane electrodialysis and a sulfur autotrophic denitrification column, and they observed a 95.8 % NO 3 − −N removal without NO 2 − −N accumulation and an effluent SO 4 2− concentration of 202.1 mg/L. However, the previous studies of coupled denitrification reported the separation of sulfur autotrophic denitrification process from the BER process (Wang and Qu 2003;Wan et al 2011). In fact, such separation is not conducive to create synergy between the sulfur autotrophic and hydrogenotrophic denitrification processes.…”