微藻为营养源固定化硫酸盐还原菌对含铜废水动态去除试验研究

Immobilized sulfate reducing bacteria beads using microalgae as nutrient source for effective biotreatment of copper-containing wastewater in an upflow anaerobic reactor

从底泥中筛选了一株脱硫弧菌属(Desulfovibrio)硫酸盐还原菌(SRB),选取易分解的普通小球藻、斜生栅藻、羊角月牙藻、螺旋鱼腥藻作为其营养源,以聚乙烯醇和海藻酸钠为主要包埋材料制备固定化SRB微球,并采用正交实验对包埋条件进行优化,然后通过上流式厌氧反应器考察了固定化SRB微球对含铜废水的长期处理效果。结果表明:微藻经过5 d发酵可分解为丙酸、丁酸、戊酸等脂肪酸,其中斜生栅藻由于发酵产物最佳被选为SRB营养源。制备微球最优配比为聚乙烯醇用量2%、海藻酸钠1%、氯化钙6%、二氧化硅1%、菌液50 m L,而且二氧化硅与聚乙烯醇用量对硫酸盐去除率影响最大。上流式厌氧反应器在反应初期对污染物的去除以微球的吸附作用为主,5 d后SRB菌发挥作用,在反应器运行0~36 d期间Cu2+的去除率可达到98%以上,运行45 d基本失效。每克微藻对Cu2+、SO2-4去除能力分别为45.28、182.17 mg·d^(-1)。

Genus Desulfovibrio sp., belonging to the sulfate-reducing bacteria（SRB）strain, was isolated from a sludge sample. Degradable microalgae（Chlorella vulgaris, Scenedesmus obliquus, Selenastrum capricornutum, and Anabaena spiroides） were first selected as carbon sources for SRB. Then, immobilized SRB beads were prepared using polyvinyl alcohol and sodium alginate as a conventional gel matrix, and the embedding condition was optimized through an orthogonal experiment. These beads were used for the treatment of copper-containing wastewater in an upflow anaerobic reactor. Results showed that under the action of co-existing fermentative bacteria, the microalgae were first degraded to fatty acids, which could serve as a carbon source for SRB. In particular, Scenedesmus obliquus was adopted as the carbon source because its fermentation products were better. The optimal parameters for preparing immobilized beads with higher sulfate reduction rate are as follows：polyvinyl alcohol 2%, sodium alginate 1%, calcium chloride 6%, silica sand 1%, and 50 m L volume of SRB suspension.During the initial stage of the reaction, pollutant removal in the upflow anaerobic reactor was mainly due to the adsorption of immobilized SRB beads. Five days later, biological sulfate reduction played a dominant role, and Cu2＋removal rate reached more than 98% during 0~36 days of reaction. After 45 days, the reactor ran out. In particular, the Cu2＋removal ability for microalgae was 45.28 mg·d^（-1）·g^（-1） and the SO2-4 removal ability was about 182.17 mg·d^（-1）·g^（-1）.