【作者】 梁志伟；

【导师】 徐向阳； 陈英旭；

【作者基本信息】 浙江大学 ， 环境工程， 2010， 博士

【摘要】 近年来日益加剧的水体富营养化对废水生物脱氮技术提出了新的要求,然而我国目前的生活污水和工业废水的生物处理技术对于有机污染物的控制比较有效,对氮素的去除效果不甚理想,因此开发应用高效、低能耗的新型生物脱氮工艺显得尤为重要。短程硝化和自养反硝化等脱氮工艺节省曝气量,不需要投加有机碳源,大大降低了运行费用,越来越受到研究者的关注。但是许多研究者都是通过不同功能的反应器串联来运行新型联合脱氮工艺,在单一反应器中的综合控制策略研究很少,因此联合脱氮工艺的研究还存在很多的问题,如工艺运行可控性、稳定性、影响因素等还有待于进一步探索。本课题立足于国内外新型生物脱氮的研究成果,对短程硝化和不同电子供体进行的异养与自养反硝化联合工艺进行基础性研究,考察了单一反应器中短程硝化联合脱氮工艺的实现和稳定运行的可行性与控制策略,探讨了碳源和电子供体对脱氮微生物种群结构和生物膜特性的影响。研究结果如下：1、系统研究了新型复合固定床生物膜反应器中短程硝化异养反硝化工艺快速启动和稳定运行的最佳控制策略,发现将硝化反应体系氮负荷在0.89kgN-NH4+m-3d-1条件下稳定运行,亚硝化比率达到85%以上,总氮去除率基本上稳定在90%以上。硝化生物膜表面生长的p亚群氨氧化菌属占全菌比例为64.1±5.0%,硝化菌属占全细菌的比例仅为5%左右,氨氧化菌主要分布在生物膜表面的0-80μm范围内,亚硝酸盐氧化菌主要分布在生物膜表层80μm以下的范围。2、对短程硝化硫自养反硝化联合工艺实现和稳定运行控制策略进行了研究,探讨了不同的因素对工艺稳定运行的影响效应。结果发现当硫氮摩尔比为3：2时工艺运行稳定,总氮去除率稳定在90%以上；高浓度的氨氮、亚硝酸盐氮和硫化物对微生物均会产生抑制作用,高浓度的硝酸盐对亚硝酸盐的反硝化过程存在竞争性抑制作用,同时硫化物易于转化为硫酸盐。观察生物膜发现自养菌生物膜和异养菌生物膜结构和微生物种群存在一定的差异,氨氧化菌和自养反硝化菌的优势菌种分别为亚硝化单胞菌和硫氧化菌。3、探索在自养反硝化脱氮工艺的基础上启动半短程硝化与厌氧氨氧化联合脱氮工艺的可行性,分析了半亚硝化工艺实现的最佳控制条件与稳定控制策略,结果证实进水中添加适量的碱度和水力停留时间可以很好的实现半短程硝化。联合工艺持续运行了4个多月的结果表明反应器可以稳定实验半短程硝化工艺,最后出水总氮去除率为52%,去除比值约为l：1.2-1：2.3之间。运行末期反硝化生物膜中硫氧化细菌的数量仍然占比重较大,同时存在一定数量的厌氧氨氧化菌微生物生长在生物膜内层。4、揭示了工艺运行过程中异养硝化生物膜和自养硝化生物膜的胞外聚合物成分与结构特性,结果发现提取出的自养生物膜中蛋白质、多糖、腐殖质和DNA提取总量和提取层差异较大,自养生物膜中蛋白质与多糖的比值(PN/PS)约为4-7之间,增加了自养生物絮体的疏水性能,相对于异养的絮体其结构也更加稳定,生物膜的胞外多聚物更难以提取。它们主要存在紧密附着的EPS和提取剩余物中,其中自养生物膜中有94%的蛋白质和89%的多糖在这两个提取层中,松散附着的EPS和可溶性EPS中含量较少。更多还原

【Abstract】 The classical biotechnology has been widely applied in biological nitrogen removal process of wastewater. But the new requirement has challenged the classical biotechnology of removal nitrogen with the progressive eutrophication. The organic substances in wastewater have been removed effectively from domestic and industrial wastewater by classical biotechnology, but nitrogen removal efficiency always couldn’t reach the wastewater discharge standard. Therefore it is important that researching and developing new nitrogen removal biotechnology which is free from the use of organic carbon and save the consumption of energy. In recent years, the new biotechnologies have been the focus of research all around the world. Whereas the most new nitrogen removal processes running in different reactors, few researchers was effort to implemented combined nitrogen removal processes in sole reactor. It has been many problems in those processes when it was applied in single reactor. The problems include lower stability and the difficulty of controlling. Our research based on domestic and foreign new biological nitrogen removal achievements and implemented the shortcut nitrification and autotrophic denitrification process, examined the feasibility and the stable control strategy of nitrogen removal in the single reactor. This report adopted the new biotechnology of nitrogen removal provide certain theoretical basis for the nitrogen removal technology to treatment the actual wastewater. The conclusions are as follows:1. This study examined the feasibility and the stable control strategy of shortcut nitrification and denitrification in the novel united fixed bed biofilm reactor. At the end of start-up period, the NLR was 0.89 kg N-NH4+m-3 d-1 and ammonium was almost entirely converted to nitrite. The nitrite ratio (NO2--N/(NO2--N+NO3--N)) was above 85% and total nitrogen removal percentage above 90% during the steady period. The results showed that the ammonia oxidation bacteria (AOB) community of the bioreactor consists almost entirely of Nitrosomonas spp. and Nitrosospira spp.. AOB were 64.1±5.0% of the total volume on the biofilm which reproduced in 0-80μm of the biofilm surface. Nitrite-oxidizing bacteria (NOB) were 5% of the total volume of the biofilm samples which reproduced under the 80μm of the biolfilm surface.2. Simultaneous elimination of sulfide and ammonia from synthetic wastewaters was investigated using the fixed bed biofilm reactor to evaluate the feasibility, the stable control strategy and effect of sulfide and nitrite ratios and substrate concentrations on the process performance. The effluent fluctuation at S/N ratio of 3:2 was less than at the other two ratios and nitrogen removal percentage reached 90%. High ammonia, nitrite, sulfide and nitrate concentrations in the bioreactor contributed towards the inhibition of the combined process. The observation of biofilm results proved that the autotrophic and heterotrophic biofilm structure and microbial populations were different, preponderant bacteria in nitrifier and denitrification biofilm were Nitrosomonas spp. and sulfur oxidation bacteria, respectively.3. This study investigated the feasibility and the stable control strategy of successfully achieved stable partial nitrification and Anammox processes of synthetic ammonium rich wastewater in the fixed bed biofilm reactor. The results conformed HRT plays an important role in the 50% nitrite accumulation, while half alkalinity plays a critical role in achieving the desired 50% partial nitrification in the effluent. The effluent from the bioreactor could be quite easily and very stably used as a feed to the Anammox reactor for the course of the experiment. The combination of this system with the subsequent ANAMMOX process has great potential and nitrogen removal percentage reached 52% after four months running, ammonium and nitrite removal rates were between 1:1.2 and 1:2.3. The results showed that the sulfur oxidation bacteria community of the bioreactor consists most of bacteria and Anammox bacteria reproduced in bottom of the biofilm.4. In this study, we examined the composition and distribution of extracellular polymeric substances (EPS) that were extracted from autotrophic nitrifying biofilm and activated sludge. The results for EPS content, including carbohydrates, proteins, humic and DNA, with different layers changed great. Autotrophic biofilm PN/PS ratios were 4-7 and the cell hydrophobicity were increased which make the extraction of EPS became harder. The TB-EPS and pellets are mainly composed of carbohydrates and proteins. There are about 94% proteins and 89% carbohydrates associated with TB-EPS and pellets layers. In contrast, there were almost no proteins in slime and LB-EPS.更多还原