为研究和评价电化学强化自养硫酸盐还原连续运行工艺,提高处理能力,设计三维复合生物阴极,构建生物-电化学耦合系统,通过促进氢气传质、增大自养微生物量及电场强化的方式,提高以H2为电子供体的硫酸盐还原速率,并评价了体系连续运行脱硫效应.结果表明,当电流为0.50 mA、系统运行较为稳定时平均硫酸盐去除负荷为1.94 g/(L·d),最大去除负荷为2.23 g/(L·d).相同水力条件下,改变进水负荷时,优化传质和电场强化的耦合反应器具有更高的系统稳定性.扫描电镜观测发现,除膜丝外,石墨纤维毡表面附着大量微生物,显著提高体系生物量.PCR-DGGE种群结构分析表明,与接种菌源相比,种群丰度略有降低,群落结构得以优化,优势菌群为脱硫弧菌属和脱硫微菌属.传质优化、生物量提高、微生物群落结构优化及电场强化是系统具有较高硫酸盐还原能力以及适应能力的关键.
To study and evaluate the performance of the continuously-operated autohydrogenotrophic sulfate reduction technique enhanced with electrochemical method and to improve the sulfate removal efficiency,a combined bio-electrical sulfidogenic system was developed with a three-dimensional bio-cathode.Sulfate reduction rate was elevated markedly owing to H2 mass transfer enhancement,biomass augmentation and electrical field stimulation.Indeed,when a current of 0.50 mA was applied to the system,the average sulfate removal load was 1.94 g/(L·d) during the stable running status and the maximum removal load was 2.23 g/(L·d).Furthermore,the combined bio-electrical system was comparatively more stable in terms of response to the variation of influx load under the same hydraulic conditions.Results of SEM showed that besides the bacteria attached on the surface of the hollow fiber,large amount of biomass was aggregated on the surface and the inner gridding space of the graphite felt.PCR-DGGE analysis indicated that the diversity of the microbial community structure was slightly reduced resulting in an optimized one.The dominant genera were Desulfovibrio and Desulfomicrobium.Enhanced H2 mass transfer,biomass augmentation,optimized microbial community structure and electrical stimulation were the key important factors for the high sulfate reduction efficiency of the system.