复合垂直流构建湿地基质酶活性与污水净化效果

The Correlation Between the Substrate Enzymatic Activities and Purification of Wastewater in the Integrated Vertical Constructed Wetland

构建湿地是 2 0世纪 70年代兴起的处理污水的生态工程 ,由于其具有建造、运行和日常管理费用低廉 ,处理效果稳定 ,且适用面广 ,越来越受到世界各国的重视。这种污水处理技术在发展中国家有着十分广泛的应用前景。本文研究与揭示了复合垂直流构建湿地基质中的磷酸酶和脲酶活性及与污水净化效果的关系 :1不同类型湿地基质酶活性不同 ,甚至不同月份的酶活性也不相同。2不同深度基质中的酶活性是不相同的。 3基质磷酸酶的活性与复合垂直流构建湿地对污水中总磷 ( TP)、无机磷 ( IP)以及化学需氧量 ( CODCr)的去除率有很显著的相关关系。 4脲酶的活性与凯氏氮 ( KN)的去除率相关性极显著。这些为利用酶活性强度作为评价净化效果和挑选合适湿地植物的指标提供了理论依据。

China is a country suffering water scarcity, with serious water pollution and water resource waste. Constructed wetlands as an ecological engineering to treat wastewater were prevailed since 1970s, and are increasingly used to treat domestic sewage, industrial wastewater and agricultural runoff in recent decades. This wetland treatment process has been obtaining international interests and applications due to its low maintenance and operation costs, and high removal capacity for water pollution control. By utilizing constructed wetland, the investment and cost for waste water treatment is just about 1/10～1/2 of those of traditional wastewater treatment plants, but its water quality of outflow can reach even above the second level wastewater treatment standard. Constructed wetland is a very potential wastewater treatment technology in developing countries.\;Many papers on the mechanisms of constructed wetland treating wastewater have been reported in the past few years. The common theory is that substrate; wetland plants and microorganisms mainly conduct wastewater purification. Substrate enzyme is a kind of biocatalyst, and it can promote chemical reaction of organic compounds in the substrate. The exist of substrate enzymes is due to the results of the activities of substrate microorganisms, animals and plant roots. Substratum enzymes play very important role in the processes of many important biochemical reactions, such as formation and decomposition of humus, hydrolysis and transformation of resides of organic compounds, plants and microorganisms, and oxidation-reduction reactions. Among them, phosphatases and urease are the most important in material transform. Phosphatases can make hydrolysis of organic phosphates easier. The enzymatic activities of urease in the wetlands are obvious related to the number of microorganisms, contents of organic material and total nitrogen.\; The substrate activities of phosphatase and urease, together with removal rates of total phosphorus(TP)、inorganic phosphorus (IP)、total nitrogen(KN)、BOD_5 、COD_ Cr 、TSS in the integrated vertical flow constructed wetland (IVCW) were measured. Colorimetric analysis was adapted to measure the substrate enzymatic activities, traditional methods were used to measure the physico-chemical parameters. The results were as follows: (1) Substrate enzymatic activities of different wetlands were different, even in different months they were different. It probably indicated that purification ability of different wetland plants was variant, and it was very necessary to choose wetland plant species in order to achieve ideal treatment performances. (2). Substrate enzymatic activities in the different layers were different. The result can be used to improve the structure of constructed wetland. (3). There was significant correlation between activities of phosphatases in the substrate and removal rates of TP( r =0.8923), IP (r =0.9903) and COD_ Cr ( r =0.9472). It probably proved that activities of phosphatase in the substrate were important factor in the removal of TP, IP and COD_ Cr . (4)There was significant positive correlation between activities of urease in the substrate and removal rates of KN( r =0.9634). It probably indicated that activities of urease in the substrate were responsible for removal of KN in the constructed wetlands. In general, all these conclusions will give reference to future researches on utilizing substrate enzymatic activities as evaluating purification efficiency and choosing ideal wetland plant species.