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/m2 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, km 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 NmLCH4/gVSSadded, and a moderate biomass biodegradability of 41%. As a result, the net energy consumption of the process was estimated at 0.5 kWh/m3 of treated municipal wastewater, considering an energy demand for illumination of 0.67 kWh/m3 and an energy recovery attributed to the anaerobic digestion of 0.17 kWh/m3 from the excess PPB biomass wasted from PAnMBR.

中文翻译：

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使用光厌氧膜生物反应器在低红外辐射下通过紫色光致细菌处理市政废水。

光能是光养系统的主要成本之一。这项研究评估了紫色光敏细菌厌氧膜生物反应器（PAnMBR）在低辐照下用于处理城市废水的光反应器效率。研究了在800-900 nm波长范围内发射的红外（IR）灯产生的3.0和1.4 W / m2的红外辐照度水平，最终目的是优化辐照能量需求。实验和建模结果表明，PPB具有在较低的辐照度下生长和处理市政污水的能力，出水水质低于TCOD˂50mg / L，TN˂10mg / L和TP˂1mg / L的目标限值。尽管确定Monod动力学参数km和Y低于以前的高能研究（分别为1.9 mgCOD / mgVSS-d和0.38 mgVSS / mgCOD），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最多可降低97％。为了确定处理过程是否可以达到能量中和，随后对残留的PPB生物质进行厌氧消化实验证明，回收的沼气具有高达240 NmLCH4 / gVSS添加的潜力，且生物质的生物降解度为41％。结果，该过程的净能耗估计为0.5 kWh / m3处理过的市政废水，考虑到照明的能源需求为0.67 kWh / m3，并且由于厌氧消化而产生的能量回收为0.17 kWh / m3。从PAnMBR中浪费掉了多余的PPB生物量。为了确定处理过程是否可以达到能量中和，随后对残留的PPB生物质进行厌氧消化实验证明，回收的沼气具有高达240 NmLCH4 / gVSS添加的潜力，且生物质的生物降解度为41％。结果，该过程的净能耗估计为0.5 kWh / m3处理过的市政废水，考虑到照明的能源需求为0.67 kWh / m3，并且由于厌氧消化而产生的能量回收为0.17 kWh / m3。从PAnMBR中浪费掉了多余的PPB生物量。为了确定处理过程是否可以达到能量中和，随后对残留的PPB生物质进行厌氧消化实验证明，回收的沼气具有高达240 NmLCH4 / gVSS添加的潜力，且生物质的生物降解度为41％。结果，该过程的净能耗估计为0.5 kWh / m3处理过的市政废水，考虑到照明的能源需求为0.67 kWh / m3，并且由于厌氧消化而产生的能量回收为0.17 kWh / m3。从PAnMBR中浪费掉了多余的PPB生物量。