单室微生物电解池处理黄水产甲烷

Simultaneous yellow water treatment and methane production using stainless steel single-chamber microbial electrolysis cell

为进一步挖掘酿酒副产物黄水的资源化利用空间,构建不锈钢单室微生物电解池(MEC)处理黄水并实现能源回收.以4%的黄水为基质,考察不同外加电压(0.4V、0.6V、0.8V、1.0V)对黄水处理过程中化学需氧量(COD)去除、各有机酸降解、甲烷产生及能量平衡等的影响.结果表明,当外加0.8V电压时,MEC中COD去除率达到94.90%±0.70%,较对照组(AD)的82.00%±0.70%增加了12.90%±0.74%.同时,COD去除负荷达(5.27±0.51)kgm^(-3)d^(-1),是AD(3.45±0.09)kgm^(-3)d^(-1)的1.53倍.对反应中甲烷产生速率和有机酸组分变化分析表明,当外加0.6V电压时,MEC中的甲烷产生速率为(1818.54±145.77)mLL^(-1)d^(-1),比AD(1014.88±121.44)mLL^(-1)d^(-1)增加了78.19%;当外加电压为0.8V时,MEC中的乙醇去除速率为(102.37±14.65)mgL^(-1)h^(-1),是AD组(57.31±10.45)mgL^(-1)h^(-1)的1.79倍;AD组的最高丙酸浓度高达(1436.10±84.42)mg/L,而外加1.0V电压的MEC组,其最高丙酸浓度为(845.57±76.72)mg/L,较之降低了(590.53±7.73)mg/L.当反应周期结束时,AD中残留的乙酸和丙酸浓度分别是MEC(外加0.8V电压)中的93.57和5.31倍.最后,反应器能量平衡分析的结果表明,当外加电压为1.0V时,其能量产生与净能量产生分别达到了(3.93±0.48)kWhkg^(-1)、(3.80±0.48)kWhkg^(-1),较AD组(2.92±0.37)kWhkg^(-1)分别增加了(1.01±0.12)kWhkg^(-1)、(0.88±0.12)kWhkg^(-1),且MEC均获得了较AD组更多的净能量.综上表明该MEC可有效促进黄水处理效率并回收甲烷,其最佳外加电压为0.8V.

To investigate the use of recycled yellow water, this study used a single-chamber membrane-less microbial electrolysis cell （MEC） with stainless steel cathode to degrade yellow water for methane production and energy recovery. By comparing with the traditional anaerobic digester （AD）, the effects of externally applied voltage （0.4 V, 0.6 V, 0.8 V, 1.0 V） on COD removal efficiency, organic acid degradation, methane production, energy recovery, and so on were studied. The results showed that COD removal efficiency was raised from 82.00% ± 0.70% in the AD to 94.90% ± 0.70% in the MEC, and COD load removal in the MEC reached 5.27 ± 0.51 kg m-3 d-1, which was 1.53 times that of the AD （3.45 ± 0.09 kg m-3 d-1）, when the applied voltage in the MEC was 0.8 V. The rate of methane production in the MEC （0.6 V applied） was 1 818.54 ± 145.77 mL L-1 d-1, which increased by 78.19%, relative to the AD （1 014.88 ± 121.44 mL L-1 d-1）. Meanwhile, when the applied voltage was 0.8 V, the rate of ethanol removal in the MEC was 102.37 ± 14.65 mg L-1 h-1, which was 1.79 times that of the AD （57.31 ± 10.45 mg L-1 h-1）. The maximum propionate concentration in the AD was 1 436.10 ± 84.42 mg/L; however, contrastingly, that of the MEC （845.57 ± 76.72 mg/L） was reduced by 590.53 ± 7.73 mg/L, when the applied voltage was 1.0 V. Moreover, when the reaction cycle was completed, the remaining concentrations of acetate and propionate in the AD were 93.57 and 5.31 times those of the MEC, respectively, when the applied voltage was 0.8 V. Finally, the results of the energy？balance？analysis indicated that energy production and net energy production in the MEC （1.0 V） were 3.93 ± 0.48 and 3.80 ± 0.48 kWh kg-1, which increased by 1.01 ± 0.12 and 0.88 ± 0.12 kWh kg-1, respectively, compared with the AD, and net energy in the MEC was greater than that in the AD. To conclude, the stainless steel single-chamber microbial electrolysis cell can effectively enhance yellow-water degradation, and carry out high methane production, when the optimal applied voltage is 0.8 V.