废水同步脱硫脱氮关键工艺参数及微生物群落结构的研究

大量未经处理的含硫化物和硝酸盐废水的排放将带来严重的环境问题.根据以废治废原则,使用厌氧滴滤塔反应器构建的同步脱硫耦联反硝化脱氮反应(SDD)能很好的去除废水中S~(2-)和NO-x-N.其中以聚氨酯泡沫为填料的厌氧滴滤塔反应器中生物活性最强,脱氮脱硫效果最好.体系中功能菌优先将S~(2-)氧化成S0,待S~(2-)去除完全后,再进一步将S0氧化成SO_4~(2-).同时,SDD反应降解NO_3~--N的速率快于NO_2~--N.进水S/N摩尔比越大,产物中SO_4~(2-)相对含量越低.结合实际工程考虑,应控制进水S/N摩尔比在5/3~5/2之间,S~(2-)浓度控制在538 mg·L-1以下.微生物群落结构分析结果表明,Thiobacillus属在4组反应器上占绝对优势,其相对丰度均高于40%.其次相对丰度较高的Rhodanobacter、Arenimonas和Truepera属与厌氧反硝化作用密切相关.对4组反应器中微生物进行Alpha-多样性分析结果表明取得较好脱硫耦联反硝化效果的体系中物种多样性指数也较高.

the key process parameters and microbial community in the wastewater treatment by simultaneous desulfurization coupled denitrification

A large amount of untreated wastewater which contains sulfide and nitrate caused serious environment problems. The simultaneous desulfurization coupling denitrification systems based on the anaerobic biotrickling filter reactor could remove S^2- and NO_x^--N in wastewater according to the principle of "treating waste with waste". Among all the packing materials, the biofilm growing on the polyurethane foam had the strongest biological activity and the highest efficiency of desulfurization and denitrification. The functional bacteria in the biofilm preferred oxidizing S^2- to S⁰ and then further oxidizing S⁰ to SO₄^2- after S^2- was removed completely.Meanwhile, the degradation rate of NO₃^--N was faster than that of NO₂^--N. The relative content of SO₄^2- in the product was lower with the increasing of influent S/N molar ratios. Considering the actual application, the influent S/N molar ratios should be controlled between 5/3~5/4 and the influent concentration of S^2- should be below 538 mg·L^-1. The results of microbial community analysis show that Thiobacillus genus had an overwhelming superiority in the four reactors and the relative abundance was higher than 40%. Rhodanobacter, Arenimonas and Truepera genus with relatively high abundances were closely related to anaerobic denitrification. Alpha-diversity analysis of microorganisms in the four reactors shows that the system was more effective, accompanying higher the species diversity index.