潜流人工湿地中的基质作用及污染物去除机理研究

发布时间：2018-03-18 15:47

本文选题：潜流人工湿地　切入点：基质　出处：《西安建筑科技大学》2017年博士论文　论文类型：学位论文

【摘要】：针对基质在人工湿地净化污水中的重要作用,基于因地制宜和生态低耗的理念,以炉渣和砾石为基质开展了潜流人工湿地污染物去除的机理研究。通过批次实验,分析了炉渣和砾石对磷的吸附机理及其影响因素;结合两种基质潜流人工湿地对污染河水的净化效果,揭示了主要污染物在潜流人工湿地中的降解与去除规律;通过基质对人工湿地植物与微生物群落的作用分析,判明了人工湿地中基质-植物-微生物之间的生态效应机制;通过两种基质潜流人工湿地中微生物群落的季节性变化特征与污染物去除效果的相关性分析,明确了潜流人工湿地的污染物去除机理。本研究主要的结论如下:(1)基质的静态吸附试验结果表明,炉渣对磷的吸附符合Freundlich吸附等温线的规律,砾石对磷的吸附符合Langmuir吸附等温线的规律,炉渣和砾石的理论吸附量分别为3.15mg/g和0.81mg/g。准二级动力学方程可较好的描述两种基质的吸附动力学特性,且物理吸附、化学吸附和配位体交换是磷吸附去除的主要作用原理。炉渣的吸附性能基本不受初始pH、有机物种类和浓度、氨氮浓度的影响,但砾石的吸附量随着pH、氨氮浓度的增加而有所减少。(2)炉渣和砾石为基质的两组潜流人工湿地,在四年的运行过程中,对SS、COD和BOD5均有较好的处理效果;运行前两年,炉渣潜流湿地对SS、COD和BOD5的去除率可分别达到90%、72%和84%,均高于砾石潜流湿地的去除效率;后两年,随着湿地内部环境逐渐趋同,两组湿地对SS、COD和BOD5的去除效果也趋于一致。且在四年运行过程中,两组湿地SS、COD和BOD5的单位面积去除量均随着进水负荷的增加而线性增加。(3)湿地运行的前两年,两组湿地对TN和NH_3-N的去除效果相近,随着湿地运行时间延长,砾石潜流湿地对TN和NH_3-N去除效果逐渐优于炉渣潜流湿地。湿地运行的四年中,炉渣潜流湿地保持了对TP和PO_4-P的较高去除率,高于砾石潜流湿地10%以上,且TP单位面积去除量有随进水负荷增加而增大的趋势。(4)湿地运行的第一年不存在空间约束的条件下,两组湿地中植物均急速生长,与炉渣潜流湿地相比,砾石潜流湿地更有利于植物的持续生长,在第四年植物收割季,砾石潜流湿地的植物生物量和生长密度分别比炉渣潜流湿地高出25株/m2和0.3 kg/m2。且在砾石潜流湿地中,植物对营养物去除的贡献率更高。两组湿地中,植物根系的微生物群落多样性均高于基质区,且根系的好氧环境激发了特征根系微生物Acinetobacter calcoaceticus的产生。(5)两组潜流人工湿地中,冬季的微生物多样性高于夏季;在冬季,进水区的微生物多样性高于出水区,而在夏季,出水区的微生物多样性反而较高。聚类分析结果表明,两组湿地基质样品的相似度较高,进出水区域微生物群落的相似度为75.15-88.06%,说明炉渣和砾石潜流湿地内部具有相近的氧环境,且在冬季也检出了反硝化菌,说明潜流湿地具有较好的保温效果。湿地冬季进水DO较高,而夏季进水DO较低,但存在沿程DO增加的趋势,双因素方差分析结果表明,DO浓度是影响湿地中微生物群落的主要因素。(6)潜流湿地对SS和TP的去除效果受季节影响不大,但COD和BOD5的去除效果在夏秋两季较好,冬春两季相对较差;TN和NH_3-N的去除受季节影响最大。且TN的去除与微生物多样性指数显著相关。潜流人工湿地的脱氮效果与进水溶解氧含量密切相关,冬季进水DO为4.6±0.15mg/L,硝化条件较好,NH_3-N转化为‘’NO3-N的效率较高,但反硝化作用不明显;夏季进水DO浓度低于0.5 mg/L,虽然沿水流可上升到2 mg/L左右,但总体上硝化条件受限,而反硝化效果反而较好。
[Abstract]:The matrix plays an important role in artificial wetlands in the local conditions and ecological consumption based on the concept of matrix mechanism carried out wetland contaminant removal with cinder and gravel. Through batch experiments, analyzes the factors of slag and gravel adsorption mechanism of phosphorus and its influence; combined with the purification effect of two kinds of matrix constructed the wetland of polluted river water, and reveals the degradation and removal of the main pollutants in the subsurface flow constructed wetland; through the effect of matrix on plant and microbial community analysis of artificial wetland, and ascertain the mechanism of ecological effect between matrix and artificial wetland in plant microbe; correlation analysis of seasonal variation characteristics and removal efficiency of pollutants by microbial community two kinds of substrates in the SSFW, the pollutants in subsurface flow constructed wetland removal mechanism. The main research conclusions Are as follows: (1) static adsorption test results show that the matrix, adsorption of phosphorus slag with Freundlich isotherm of adsorption of phosphorus on gravel with Langmuir isotherm of adsorption theory of slag and gravel were 3.15mg/g and 0.81mg/g. adsorption kinetics of two quasi kinetic equation can well describe the two kinds of matrix the physical adsorption and chemical adsorption, and ligand exchange is the main effect of phosphorus removal by adsorption principle. The adsorption performance of slag is not affected by the initial pH, organic matter type and concentration, the effect of ammonia concentration, but the adsorption capacity of gravel with pH, increased ammonia concentration decreased. (2) and slag the two group of gravel for the matrix constructed wetland, in the process of four years, of SS, better treatment effect COD and BOD5 respectively; two years ago, the slag flow wetlands on SS, COD and the removal rate of BOD5 Respectively 90%, 72% and 84%, were higher than that of gravel in the subsurface wetland removal efficiency; after two years, with the gradual convergence of the internal environment of wetland, wetland two groups of SS, COD and BOD5 removal efficiency also tended to be the same. And in the process of four years, two groups of wetland SS, unit area COD and BOD5 removal with the increase of the influent load increases. (3) two years ago, wetland, removal efficiency of TN and NH_3-N of the two groups are similar with the wetland wetland, prolonging the running time, the removal effect was better for TN and NH_3-N slag subsurface wetland gravel subsurface wetland. For four years running of wetland in slag subsurface wetland maintained the TP and PO_4-P removal rate is higher, higher than that of the gravel subsurface wetland is above 10%, and the TP removal rate per unit area increase with the water load. (4) the first year of operation of the wetland there is no space constraints, two groups of wetland vegetation All the rapid growth, compared with the slag subsurface constructed wetland, gravel wetland more conducive to the sustainable growth of the plant, in the fourth year plant harvest season, gravel subsurface wetland plant biomass and growth density were 25 higher than slag subsurface wetland plants of /m2 and 0.3 kg/m2. and the flow wetland in the gravel potential, plants on nutrient removal the contribution rate is higher. Two groups of wetlands, the microbial community diversity of plant roots were higher than that of the matrix, aerobic environment and root excitation characteristics of root microorganism Acinetobacter calcoaceticus. (5) two groups of subsurface flow constructed wetland in winter microbial diversity is higher than in summer; in winter, the water area microbial diversity is higher than that of the water outlet area, and in the summer, but higher water area of microbial diversity. The results of cluster analysis showed that two groups of wetland samples with high similarity, import water domain microbial community The similarity of 75.15-88.06%, shows the internal slag and gravel subsurface flow wetland has similar oxygen environment, and also detected the denitrifying bacteria in the winter, that subsurface wetland has good thermal insulation effect. The wetland water in winter and summer DO high influent DO was low, but increased along the DO trend, two factor variance analysis results show that the DO concentration is the main factor affecting the microbial community in the wetland. (6) on the removal of SS and TP in subsurface flow wetland affected by season is not big, but the removal effect of COD and BOD5 in the summer two season better in the two season is relatively poor; TN and NH_3-N removal was affected by season. No significant correlation with TN the removal and microbial diversity index. The nitrogen removal effect of subsurface flow constructed wetland is closely related with the water content of dissolved oxygen, water in winter DO was 4.6 + 0.15mg/L, nitrification condition, the conversion of NH_3-N to "NO3-N" but with high efficiency. The denitrification is not obvious. The DO concentration in summer is less than 0.5 mg/L, although it can rise to 2 mg/L along the current, but the nitrification condition is limited in general, and the denitrification effect is better.

【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X703

【相似文献】