垂直流人工湿地启动期基质酶的时空变化

Spatial distribution of substrate enzyme in the vertical flow constructed wetland

为了解垂直流人工湿地系统中基质酶在去污效果中的作用及其随基质深度和运行时间的变化规律,设置3个垂直流人工湿地系统：种植皇竹草的A系统,种植象草的B系统,以及不种植物的C系统。分别监测3个系统不同基质深度与不同运行时间条件下脲酶、磷酸酶、过氧化氢酶、转化酶和纤维素酶的变化规律,以及这几种酶与TN、TP、COD、NH＋4-N和NO-3-N污染物之间的相关性。实验结果表明,上述5种酶都表现出随着基质深度增加而减少的趋势,且上层0～30cm处的基质酶活性极显著高于中层和底层的酶活性,此外,种植能源植物的A、B系统基质酶活性都高于不种植物C系统,说明湿地中污染物的去除主要集中在上层基质,种植能源植物能够有效促进微生物的活性,增加胞外酶的分泌,提高人工湿地对污染物的去除效果,可为优化人工湿地除污效果以及湿地植物的选择提供理论依据。

In this study,we established 3 vertical flow constructed wetland（ VFCW） systems,namely,system A（ by planting Pennisetum sinense Roxb.）,system B（ by planting Pennisetum purpureum Schum.）,and system C（ no planting）,to understand the spatial distribution and characteristics of a substrate enzyme and its relationship with different concentrations of TN,TP,COD,NH＋4-N,and NO-3-N. Changes in the functions of urease,phosphatase,catalase,invertase,and cellulose at different depths and times in the 3 VFCW systems were also monitored. In addition,the correlation between TN,TP,COD,NH4-N,and NO-3-N concentrations and the enzymes was investigated. Our results showed that the activity of the 5 enzymes decreased with an increase in depth. Enzyme activities were significantly higher with substrates on the top than with those at the bottom and in systems A and B than in system C. Our results suggested that substrates on the top play a critical role in removing pollutants present in wetlands and that planting energy plants effectively promotes the activity of microorganisms and increases the secretion of extracellular enzymes that directly remove contaminants from wetlands. Our findings provide a theoretical basis for optimizing pollutant removal efficiency and for selecting wetland plants.