人工湿地植物根际微生物对4种污水重金属元素的净化能力

Purification mechanism of four kinds of sewage heavy metal elements by plant rhizosphere microorganisms in constructed wetland

【目的】研究人工湿地植物根际微生物对4种污水重金属元素的净化能力。【方法】用实验室已有的10株菌株,测定不同时间污水重金属浓度及菌株吸附率,并拟合细菌与真菌平均吸附率模型,分析不同根际微生物对重金属吸附净化能力的影响。【结果】①10株高效菌株对不同浓度污水Pb^(2+)的吸附率高(H)、中(M)、低(L)范围分别为27.30%~52.27%、32.17%~56.07%、32.17%~56.07%,F_(26)(Aspergillus iizukae)、B_(19)(Bacillus megaterium)分别是高、中低浓度下的高效菌株;菌株对不同浓度污水Cd^(2+)的吸附率范围为29.63%~56.00%(H)、31.03%~58.70%(M)、31.53%~59.23%(L),B_(19)、F_(9)(Westerdykella dispersa)分别是高低、中浓度下的高效菌株;菌株对不同浓度污水Cu^(2+)的吸附率范围为29.03%~55.73%(H)、29.83%~57.73%(M)、35.10%~59.00%(L),F_(25)(Penicillium janthinellum strain)是3个浓度下的高效菌株。菌株对不同浓度污水Zn^(2+)的吸附率范围为29.67%~56.73%(H)、31.27%~58.10%(M)、36.00%~60.27%(L),F_(16)(A.niger strain)是3个浓度下的高效菌株。②不同处理时间、污水金属初始浓度和菌株种类均对吸附污水中重金属离子的效果有显著影响,菌株对重金属的吸附效果在低浓度和48 h最优且真菌优于细菌,细菌平均吸附率符合指数函数模型,真菌平均吸附率符合幂函数模型。③微生物吸收阶段的参与度以及分泌物数量可能是影响重金属吸收效果的主要内在机制。【结论】研究结果为城市重金属污水处理系统中高效菌种的选择提供了理论依据。

【Objective】The study aimed to explore the mechanism of heavy metal purification by plant rhizosphere microorganisms in constructed wetland.【Method】10 high-efficient strains were isolated and screened from rhizospheric soil of Thalia dealbata,Vetiveria zizanioides and Arundo donax var. versicolor.The concentrations of heavy metal in sewage water at different times and the adsorption rate of strain were determined and the model of average adsorption rate of bacteria and fungi were fitted.【Result】(i)The rates of high(H),medium(M) and low(L) adsorption of the 10 high-efficient strains in different concentrations of Pb^(2+) sewage were 27.30%-52.27%,32.17%-56.07% and 32.17-56.07%,respectively.Aspergillus iizukae(F_(26)),was the most high-efficient strain in sewage of high concentration, and Bacillus megaterium(B_(19)),was the most high-efficient strain in sewage of medium and low concentration.The adsorption of the different strains in different concentrations of Cd^(2+) sewage were 29.63%-56.00%(H),31.03%-58.70%(M),31.53%-59.23%(L),respectively.B_(19)was the most high-efficient strain in sewage of high and low concentration. Westerdykella dispersa(F_(9)) was the most high-efficient strain in sewage of medium concentration.The adsorption of the different strains in different concentrations of Cu^(2+) sewage were 29.03%-55.73%(H),29.83%-57.73%(M),35.10%-59.00%(L),respectively.Penicillium janthinellum strain(F_(25)) was the most high-efficient strain in sewage of 3 different concentrations.The adsorption of the different strains in different concentrations of Zn^(2+) sewage were 29.67%-56.73%(H),31.27%-58.10%(M),36.00%-60.27%(L),respectively. A.niger strain(F_(16)) was the most high-efficient strain in sewage of 3 different concentrations.(ii) The results of multivariate analysis of variance indicated that different processing time, initial concentration of metal in sewage and the types of strains had significant impacts on the effects of adsorption of heavy metal ions in sewage.The best effect of adsorption of strains in heavy metal is in low concentration of sewage and 48 h, and the adsorption effects of fungi were superior to that of bacteria.The average adsorption rate of bacteria conforms to the model of exponential function, and the average adsorption rate of fungi conforms to the model of power function.(iii) Participation in microbial absorption stage and quantity of secretions maybe the main internal mechanism affecting the absorption of heavy metals.【Conclusion】The results would provide theoretical basis for the selection of high-efficient strains in the heavy metal wastewater treatment system.