垂直流人工湿地条件优化及其微生物多样性研究

发布时间：2018-04-13 10:33

本文选题：人工湿地 + 植物组合　；参考：《浙江大学》2015年硕士论文

【摘要】：人工湿地作为一种经济有效的污水处理方式,过去几年中得到迅速发展与推广,然而传统人工湿地主要通过原始湿地改建而来,其处理效果和应用范围受到很大限制。环境温度变化影响着湿地系统中微生物的活性,对湿地处理效果具有很大影响。针对传统湿地系统冬季低温处理性能不佳等问题,优化湿地运行条件,构建固定化生物膜复合流生态湿地工艺,开展固定化生物膜强化湿地系统运行稳定性研究,有效控制水体中有机物及氮等污染物。另外,湿地温室气体的排放作为一种湿地运行的副产物受到人们越来越多的关注,本文对不同湿地系统中甲烷的排放进行检测并对其机理进行研究分析,为提高湿地运行效果、保护生态环境提供理论指导。本研究主要得出以下结论：(1)通过微宇宙实验研究单种和混种植物人工湿地对人工污水的处理效果、甲烷释放及其相应的微生物学机理,发现植物混种可以提高污水处理效率,但是较高的CH4释放活性削弱了其环境效益。对不同植物种类及丰度条件下微生物多样性进行分析,发现植物对产甲烷古菌和甲烷氧化菌的群落结构影响不大,而在不同湿地系统中甲烷氧化菌的丰度差异较大,可能是导致湿地甲烷释放差异的主要原因。另外,在本研究体系中,种植羊蹄在湿地污染物的去除过程中发挥着重要作用并可能对甲烷释放产生重要影响。(2)比较分析了四个水力负荷(0.2、0.4、0.8和1.6m.d-1)对复合垂直流人工湿地系统污染物去除及甲烷排放的影响发现,随着水力负荷(HL)增加,湿地对NH4+-N去除率逐渐降低(88%、87%、83%和76%),但对N03--N和CODMn的去除效率无显著变化；由于湿地进水溶解氧(DO)含量较低,因此湿地有机物的去除主要以厌氧降解为主,HL的提高会导致CH4排放的增加,综合考虑污染物去除及甲烷排放的环境效益,可控制湿地运行的HL为0.8 m.d-1。不同HL条件下,湿地系统中微生物群落结构变化不明显,但Down-flow和Up-flow之间微生物群落结构变化较大；湿地中硝化细菌主要为Nitrosomonas和Nitrospira,湿地Up-flow中菌群多样性丰富,受HL影响较大,湿地Down-flow中氨单加氧酶基因amoA相对含量高于Up-flow,并且随着HL的增加逐渐降低；反硝化菌在湿地中种类丰富,受HL影响显著,亚硝酸还原酶基因nirS的相对含量要显著高于amoA基因,高HL (1.6 m·d-1)条件下湿地Down-flow和Up-flow中nirS基因的相对含量显著高于其它HL,说明反硝化菌群丰富,从而维持了N03--N稳定高效地去除。对湿地Down-flow湿地中产甲烷古菌和甲烷氧化菌的分析发现产甲烷古菌的相对含量随着HL的增加而呈递增趋势,导致高HL条件下较高的甲烷释放能力；甲烷氧化菌的含量仅在高(1.6 m.d-1)、低(0.2 m·d-1)HL之间存在差异。对其菌群结构进行分析发现本实验系统中产甲烷古菌种类丰富,主要属于Methanomicrobiales,不同HL条件下菌群结构差异较大,甲烷氧化菌主要属于Methylocystaceae,受HL影响较小。(3)复合垂直流人工湿地对微污染水源水NH4+-N具有较高的去除效率(约80%)并且随时间变化表现出较高的稳定性,NO3--N去除受环境温度影响较显著；由于进水有机物含量较低,进入湿地的有机物能够很快被消耗,所以在环境温度-4-39℃湿地的CODMn去除效率也较稳定。在不同运行阶段,湿地系统中氨氧化菌群表现出较高的相似性,可以维持NH4+-N去除效率稳定；反硝化菌菌群结构差异较大,其含量随温度变化显著。
[Abstract]:Artificial wetland is an economical and effective way of sewage disposal, the rapid development and popularization of the past few years, however, the traditional artificial wetland mainly through original wetland reconstruction and its treatment effect and application scope is limited. The ambient temperature changes affect the activity of microorganisms in the wetland system, has great influence on wetland treatment effect in view of the traditional wetland system. The winter low temperature treatment of poor performance and other issues, to optimize the operating conditions of wetland, construction of the immobilized composite flow wetland ecological process, carry out the fixed biological film enhanced stability of the operation system of wetland, effectively control the organic matter and nitrogen pollutants in water. In addition, wetland greenhouse gas emissions as a by-product the wetland has attracted more and more attention, the emission of methane was detected in different wetland system and its mechanism Research and analysis, in order to improve the operation effect of wetlands, protect the ecological environment to provide the theoretical guidance. The main conclusions are as follows: (1) through the microcosm experiments of single and hybrid plants artificial wetland treatment of artificial wastewater, release of methane and its corresponding microbial mechanism, found that the plant mixture can improve the efficiency of sewage treatment, but the higher CH4 release activity weakened its environmental benefits. On the condition of different plant species and abundance of microbial diversity analysis showed little effect on plant community structure of methanogens and methanotrophs, and differences in the abundance of methane in different wetland system in oxidizing bacteria is larger, which may be the main reason for wetland methane release the difference in this study. In addition, in the system, in the process of removing pollutants in Rumex planting wetland plays an important role on the methane production and may release Have an important influence. (2) a comparative analysis of the four hydraulic load (0.2,0.4,0.8 and 1.6m.d-1) that influence on removal of integrated vertical flow constructed wetland system of pollutants and methane emission, with the increase of hydraulic load (HL), for the NH4+-N removal rate decreased gradually (88%, 87%, 83% and 76%), but the removal efficiency of the N03--N and CODMn had no significant change; because the influent dissolved oxygen (DO) content is low, so the wetland organic removal mainly by anaerobic degradation, the increase of HL will lead to increased CH4 emissions, and methane emissions of pollutants removal considering environmental benefits, can control the operation of the HL wetland is 0.8 m.d-1. HL under the condition of wetland microbial community structure change is not obvious, but between Down-flow and Up-flow changes of microbial community structure is relatively large; nitrifying bacteria are mainly Nitrosomonas and Nitrospira in the wetland, many bacteria in wetland Up-flow Like the rich, influenced by the HL, wetland Down-flow ammonia monooxygenase gene relative content of amoA is higher than Up-flow, and with the increase of HL gradually decreased; denitrifying bacteria species in the wetland is rich, was significantly affected by HL, the relative content of nitrite reductase gene nirS was significantly higher than that of amoA gene, HL (1.6 m D-1 and Down-flow nirS) the relative content of wetland under the condition of Up-flow gene in HL was significantly higher than the other, that denitrifying bacteria rich, in order to maintain a stable and efficient removal of N03--N. The analysis of wetland wetland Down-flow methanogens and methane oxidizing bacteria found in methanogenic archaea relative content with the increase of HL while the trend was increasing, leading to high HL under the condition of high methane content; methane oxidizing bacteria only at high (1.6 m.d-1), low (0.2 M D-1) HL. The difference between microbial community structure analysis found that the Test system of the methanogens rich species, mainly belonging to Methanomicrobiales, the difference of microbial community structure under different HL conditions, the methane oxidizing bacteria are mainly Methylocystaceae, less affected by HL. (3) composite vertical flow artificial wetland has high removal efficiency of micro polluted water NH4+-N (about 80%) and time-varying performance high stability, removal of NO3--N affected by the ambient temperature is remarkable; because of the low influent organic concentration, organic matter into the wetland can be quickly consumed, so the environmental temperature -4-39 wetland CODMn removal efficiency is also more stable. At different operation stages, in the wetland system of ammonia oxidation bacteria showed similarity high, can maintain the NH4+-N removal efficiency is stable; denitrifying bacteria structure is different, its content changes significantly with temperature.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

【参考文献】