Abstract:

Sampling was taken from different natural habitats, and 6 strains of sulfate-reducing bacteria (SRB) with the ability to efficiently remove SO{}_{\mathrm{4}}^{\mathrm{2}-} were screened out through enrichment, domestication and isolation. Through molecular biological identification, it was determined that the screened strains were Desulfovibrio. The SRB mixed flora was constructed by combining various strains to explore its desulfurization performance under acid stress. A series of batch tests were used to analyze the growth characteristics and sulfate reduction performance of the selected strains. The results showed that the optimal growth C/S ratio of the strains SRB-T3, SRB-X7 and SRB-W6 under neutral conditions was 2.5, and the sulfate reduction capacity could reach more than 0.200 kg/(m³·d). The best growth C/S ratio of domesticated strains SRB-G2, SRB-H1 and SRB-X8 under weak acid conditions is 4.0, which can adapt to low pH environment conditions (pH 5.0—6.5) quickly and reach (0.15±0.007) kg/(m³·d) sulfate reduction capacity. The above strains were combined to construct SRB mixed flora in the ratio of 1∶1∶1∶3∶6∶6, and the sulfate reduction capacity was as high as 0.401 kg/(m³·d) under neutral conditions. Acidity impact test was used to study the desulfurization performance of mixed flora. The results showed that the mixed bacterial system could have good acid resistance and stability through the complementary synergy between different strains compared with the single bacterial system. With the continuous decrease of pH (pH 6.0—5.0), the mixed bacterial system was superior to the single bacterial system in terms of microbial growth and sulfate reduction. When the pH drops to 4.5, the mixed bacterial system could gradually adapt to the acidic environment and recover the sulfate reduction function after a 12 day lag period, and reached 90% of the SO{}_{\mathrm{4}}^{\mathrm{2}-} removal rate after 28 days, while each single bacterial system showed different degrees of acid inhibition and even successively failed.

Key words: waste water, sulfate reduction, mixed flora, acid stress, repair

摘要：

从不同的自然生境中采样，经富集驯化-分离筛选出6株具有高效去除SO{}_{\mathrm{4}}^{\mathrm{2}-}能力的硫酸盐还原菌(sulfate-reducing bacteria，SRB)，经分子生物学鉴定，确定所筛菌株皆为脱硫弧菌属。采用系列批式实验对筛选菌株进行生长特性及硫酸盐还原性能分析，并将各菌株按照1∶1∶1∶3∶6∶6比例进行复配组合构建SRB混合菌群，中性条件下其硫酸盐还原能力高达0.401 kg/(m³·d)。采用低pH冲击实验探究混合菌群在酸胁迫条件下的脱硫性能，结果表明，随着pH的不断降低，混菌体系在微生物生长和硫酸盐还原等方面均优于各单菌体系；当pH降至4.5时，混菌体系在经历12 d的迟滞期后，能够逐渐适应酸性环境并恢复硫酸盐还原功能，于28 d后达到90%的SO{}_{\mathrm{4}}^{\mathrm{2}-}去除率，而各单菌体系则表现出不同程度的酸抑制甚至相继失效。SRB混合菌群的构建能够通过不同菌株之间的互补协同作用使处理系统具备良好的耐酸性和稳定性。

关键词: 废水, 硫酸盐还原, 混合菌群, 酸胁迫, 修复