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水库沉积物原位生物覆盖修复技术研究

In-Situ Biocarrier Capping Remediation Sediment in Reservoir

【作者】 蔡道健

【导师】 徐金兰; 黄廷林;

【作者基本信息】 西安建筑科技大学 , 市政工程, 2010, 硕士

【摘要】 本论文对水库沉积物原位生物覆盖技术进行研究,试验以沸石、陶粒、轻质多孔三种填料为覆盖载体,并接种从水库沉积物中分离得到的高效硝化细菌与反硝化细菌组合,制备成生物覆盖载体。将生物载体覆盖在污染沉积物表层,通过生物载体的硝化与反硝化作用,抑制和消除沉积物内源污染。本文旨在找出控制内源污染的最佳生物载体,并对沸石和陶粒的吸附动力学、不同沸石粒径、投加量对修复的影响及去除机理进行研究,为原位修复水库沉积物提供理论依据。主要结论如下:(1)沸石吸附动力学试验结果表明沸石能快速吸附氨氮,在6-9小时内吸附达到平衡。在吸附反应的初期,溶液中氨氮浓度从79.48mg/L降到23.5mg/L,吸附速率为0.47mg/(L·min),随后吸附速率降到0.09mg/(L·min)。反应初期,氨氮浓度降低速率与沸石对氨氮的吸附速率较快,随着时间越来越长,吸附反应速率减缓。沸石粒径为1-2mm的吸附速率是粒径为2-4mm的1.125倍,是粒径为4-8mm的1.5倍。(2)在对沸石及陶粒吸附氨氮的两种体系中,在这两种体系都加入硝化细菌WGX15和WGX18、反硝化细菌HF3和HF7,试验结果表明在沸石吸附氨氮的体系中,去除氨氮的效果最好。沸石量越多,去除的氨氮越多,生物去除率越高,1g沸石时生物去除率为30.56%,5g沸石时生物去除率为100%。在陶粒吸附氨氮的体系中,去除氨氮较小,当5g陶粒时去除氨氮最好,其去除率为39.9%。(3)在找出控制内源污染的最佳生物载体试验中,其结果表明轻质多孔、陶粒及沸石这三种填料对NH4+-N及TN都有去除能力,沸石的去除效果最好,对氨氮及总氮的去除率分别为89.6%、84.8%,其次是陶粒,分别为65.1%、59%,轻质多孔去除效果最不好,分别为35.6%、37.8%。因此,沸石是控制内源污染的最佳生物载体。(4)分别对粒径为1-2mm、2-4mm、4-8mm的挂膜和未挂膜沸石进行污染沉积物修复试验,发现在挂膜的条件下,对TN的去除率分别为74.05%、85.24%及78.99%,对NH4+-N的去除率分别为80%、97.92%和89.48%;在未挂膜的条件下,对TN的去除率分别为88.93%、82.81%及82.54%,对NH4+-N的去除率分别为94.41%、87.21%及91.71%。上述试验结果表明在不同沸石粒径条件下,修复效果差异不大。(5)在沸石投加量分别为160g、190g、220g、250g时,对污染沉积物进行修复试验,结果表明四组修复的效果都较好,但投加量为250g挂膜后的沸石一组去除效果最好,其TN去除率为83.15%,NH4+-N去除率为100%,可能由于沸石量越多,比表面积就越大,附着的硝化细菌及反硝化细菌就越多,对总氮去除的效果就越好。(6)在原位生物覆盖技术修复大唐芙蓉园人工湖和扬州某湖的污染沉积物时,两种沉积物的TN去除率分别为84.77%、92.25%;对NH4+-N去除率分别为89.59%、100%,表明原位生物覆盖技术是修复污染沉积物的有效技术。

【Abstract】 The study of the thesis focused on In-Situ biocarrier capping technology to remedy sediment in the reservoirs. Zeolite, ceramic, and light porous carriers are choosed. They are inoculated couple of nitrification bacteria and denitrification bacteria to make biocarrierss, and then put the biocarriers on the surface of the contaminated sediment in order to restrain and eliminate endogenesis pollution in the sediment through the mechanism of the nitrification and denitrification. The aims of the study is to find out the optimal biocarrier to control endogenesis pollution. We investigated the adsorption kinetics of zeolite and ceramic, and the effect of diameter of zeolite, dosage of zeolite on remediation to explore the mechanism of nitrogen removal. The results will provide theoretical support to In-Situ remediation sediment in reservoirs. The main results and conclusions are as follows.(1) In adsorption kinetics of zeolite experiment, the results show that zeolite can quickly adsorb ammonia, and adsorption equilibrium appear in 6-9hours. In the initial stages of adsorption, the concentration of ammonia decreases from 79.48mg/L to 23.5mg/L, and the adsorption rate is 0.47mg/(L-min), then down to 0.09mg/(L-min). In the initial reaction, ammonia concentration decrease sharply and the adsorption ammonia rate of zeolite is very fast. As time goes on, the rate of adsorption reaction decrease. The adsorption reaction rate of 1~2mm zeolite is 1.125 times of that of 2-4mm zeolite, and is 1.5 times of that of 4-8mm zeolite.(2) The experiment of adsorption ammonia with zeolite and ceramic were carried out. Which inocluted combined the nitrification bacteria WGX15 and WGX18, denitrifiation bacteria HF3 and HF7 respectively. The results show that zeolite is the best biocarrier of adsorption ammonia. The removal efficiency of ammonia depended on the mass of zeolite, and increase with zeolite mass increasing.That is to say, the biological removal efficiency is 30.56%, when the mass of zeolite is 1g, while the biological removal efficiency is 100%, when the mass of zeolite is 5g. In contrast, the mass of removed ammonia is not so much in bio-ceramic system. Under application of 5g ceramic condition the biological removal efficiency is 39.9%.(3) In the experiment of finding out the optimal biocarrier to control endogenesis pollution, the results show that zeolite, ceramic and light porous biocarriers have the capacity of removing NH4+-N and TN. We observed that the removal efficiency of NH4+-N and TN respectively is 89.6% and 84.8% in bio-zeolite system, and the corresponding date is 65.1% and 59% in bio-ceramic system. The removal efficiency of NH4+-N and TN is 35.6% and 37.8% in bio-light porous system. So, bio-zeolite is the best carrier, and the bio-ceramic is better. Light porous fillers is the worst.(4) The experiment was carried out to investigate the effect of zeolite diameter on remedying the contaminated sediment. 1~2mm,2~4mm,4-8mm of zeolite were used and carried out under inoculation or non-inoculation conditions. We observed that under inoculation condition the removal efficiency of TN is 74.05%,85.24% and 78.99%, and the removal efficiency of NH4+-N is 80%,97.92% and 89.48%. Moreover, under the non-inoculation condition the removal efficiency of TN is 88.93%,82.81% and 82.54%, and the removal efficiency of NH4+-N is 94.41%, 87.21% and 91.71%. The results mentioned above show that the TN removal is independent on the diameter of zeolite.(5) The experiment was carried out to explore the effect of zeolite dose on remediation of sediment. The zeolite dose is 160g,190g,220g and 250g in this study. The results show that the removal efficiency of TN and NH4+-N is 83.15% and 100%, when the zeolite dose is 250g. The dose of zeolite is more, and the surface area is greater, and the attached nitrifying bacteria and denitrifying bacteria is more. So removal TN is better.(6) We tested two kinds of contaminated sediment using in-situ bio-zeolite capping technology. One is taken from man-made lake of Tang Paradise, another is a lake of Yangzhou. The results show that the removal efficiency of TN is 84.77% and 92.25%, while the removal efficiency of NH4+-N is 89.59% and 100%. These results show that In-Situ biocarrier capping is a effective technique to remedy contaminated sediment.

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