Department of Civil and Environmental Engineering, Western University, London, ON, N6A 5B9, Canada.
Department of Civil and Environmental Engineering, Western University, London, ON, N6A 5B9, Canada; Department of Chemical and Biochemical Engineering, Western University, London, ON, N6A 5B9, Canada.
Water Res. 2020 Apr 15;173:115535. doi: 10.1016/j.watres.2020.115535. Epub 2020 Jan 27.
Light energy is one of the major costs for phototrophic systems. This study evaluated the photoreactor efficiency of purple phototropic bacteria anaerobic membrane bioreactor (PAnMBR) at low irradiance for the treatment of municipal wastewater. Infrared irradiance levels of 3.0 and 1.4 W/m produced by an infrared (IR) lamp emitting in the 800-900 nm wavelength range were investigated, with the ultimate goal of optimizing the irradiance energy demand. Experimental and modeling results demonstrated the ability of PPB to grow and treat raw municipal wastewater at the applied low irradiances, with effluent quality below target limits of TCOD˂50 mg/L, TN˂10 mg/L, and TP˂1 mg/L. While Monod kinetic parameters, k and Y, were determined to be lower than previous high-energy studies (1.9 mgCOD/mgVSS-d and 0.38 mgVSS/mgCOD, respectively), the photobioreactor performance were consistently maintained, indicating that energy cost associated with IR illumination can be reduced by up to 97%. To determine whether the treatment process could approach energy neutrality, subsequent anaerobic digestion experiments of the residual PPB biomass proved a potential for biogas recovery of up to 240 NmLCH/gVSS, and a moderate biomass biodegradability of 41%. As a result, the net energy consumption of the process was estimated at 0.5 kWh/m of treated municipal wastewater, considering an energy demand for illumination of 0.67 kWh/m and an energy recovery attributed to the anaerobic digestion of 0.17 kWh/m from the excess PPB biomass wasted from PAnMBR.
光能是光养生物系统的主要成本之一。本研究评估了在低光照条件下紫色光养细菌厌氧膜生物反应器（PAnMBR）处理城市污水的光反应器效率。研究了红外灯下发出的 800-900nm 波长范围内的红外辐照度水平，该灯的红外辐照度分别为 3.0 和 1.4W/m，目的是优化辐照度能源需求。实验和模拟结果表明，PPB 能够在应用的低辐照度下生长并处理原城市污水，出水质量低于 TCOD˂50mg/L、TN˂10mg/L 和 TP˂1mg/L 的目标限值。尽管 Monod 动力学参数 k 和 Y 被确定低于以前的高能研究（分别为 1.9mgCOD/mgVSS-d 和 0.38mgVSS/mgCOD），但光生物反应器的性能始终保持不变，这表明与 IR 照明相关的能源成本可以降低 97%。为了确定处理过程是否可以接近能源中性，随后对剩余的 PPB 生物质进行了厌氧消化实验，证明了生物气回收潜力高达 240NmLCH/gVSS，以及适度的生物质生物降解性 41%。因此，考虑到 0.67kWh/m 的照明能源需求和从 PAnMBR 浪费的多余 PPB 生物质厌氧消化产生的 0.17kWh/m 的能源回收，该过程的净能源消耗估计为 0.5kWh/m 处理后的城市污水。
