餐厨垃圾发酵碳源制备及其生物脱氮利用性能研究
发布时间：2018-07-31 17:07
【摘要】：碳源缺失现象普遍存在并已经成为了制约污水处理高效脱氮的重要原因,通过投加碳源强化反硝化过程是提升脱氮效率的重要途径。餐厨垃圾是城市有机固体废物的来源之一,本着“以废治废”的原则,利用其有机物含量高的特点,从餐厨垃圾制备可用碳源已成为水环境界关注的技术发展方向。基于此目的,本文以校园餐厨垃圾为基质,系统地研究了高温自由发酵和中温乳酸发酵两种碳源制备模式的特点,全面考察了发酵产物作为碳源的反硝化特性,并针对低碳氮比(C/N)生活污水处理和再生利用,开展了A/O-MBR中试研究,重点考察了碳源投加后的脱氮效率和膜污染特性。研究工作的主要成果如下:(1)提出了餐厨垃圾碳源制备的技术策略,将厌氧消化过程控制在水解和酸化阶段,以实现可用碳源的高效回收。高温自由发酵(55°C,无pH调节)能有效促进有机物水解,产物中以碳水化合物为主;中温酸性发酵(37°C,间歇调节pH至6)有利于酸化过程,能有效富集乳酸菌(Lactobacillus),产物以乳酸为主,并在OLR为14 g-TS/L·d时获得最大的乳酸产量,较高的OLR不利于乳酸发酵。(2)研究比较了不同接种对中温乳酸发酵碳源制备的影响,发现以餐厨垃圾本身作为接种时,乳酸产量最大,有机物损失量最少。微生物种群结构分析结果表明,尽管接种液中微生物种群结构差异较大,但在最优的发酵条件下,Lactobacillus能大量富集并成为优势种群,并实现基质高效转化。(3)研究提出了动态膜乳酸发酵强化技术,利用动态膜对颗粒态有机物的截留作用,延长了基质在反应器中的停留时间,增大了微生物量,强化了微生物酶活性,进而极大地提高乳酸产量。通过动态膜乳酸发酵可实现溶解性发酵产物的连续分离,从而提高发酵碳源制备效率。(4)研究揭示了中温酸性发酵条件下,有机物水解酸化过程中呈现的“碳水化合物→乳酸→VFAs”的物质转化路径,及其相关的微生物种群结构变化规律。利用未发酵、部分发酵、乳酸为主和VFAs为主的阶段产物作为碳源进行反硝化试验,结果表明,乳酸为主的发酵产物具有较高的反硝化速率和潜能,并能在C/N比大于6时实现完全反硝化。利用乳酸为主的发酵产物作为小试SBR碳源用于低C/N比实际污水处理时发现,反应器能够长期稳定运行,脱氮效率明显提高,微生物的碳源利用能力增强,微生物种群多样性丰富。(5)高温自由发酵产物虽然以碳水化合物为主,但作为外增碳源也具有良好的反硝化促进作用,且发酵液中未充分水解的颗粒态有机物也能得到生化利用,实现强化脱氮效果。以高温自由发酵产物作为补充碳源用于中试A/O-MBR系统进行低C/N比实际污水处理,结果表明,反应器能够长期稳运行定,微生物的碳源利用能力明显强化,具有降解溶解性微生物代谢产物(SMP)和复杂有机物能力的微生物种群增多,反硝化菌群相对丰度增加,脱氮效率明显提高。发酵产物投加后反应器内微生物胞外聚合物(EPS)并未明显累积,溶解性有机物(DOM)沿A/O-MBR系统处理流程逐渐降低,部分污染物被膜面泥饼层截留,长期运行过程中并未导致膜面的不可逆污染。
[Abstract]:The loss of carbon source is common and has become an important reason for restricting the efficient denitrification of sewage treatment. Strengthening the denitrification process by adding carbon source is an important way to enhance the efficiency of denitrification. In this paper, the characteristics of two carbon source models for high temperature free fermentation and medium temperature lactic acid fermentation are systematically studied based on the purpose of this purpose. The characteristics of the denitrification characteristics of the fermented products as carbon sources are investigated in this paper. Compared with (C/N) domestic sewage treatment and reuse, the pilot study of A/O-MBR was carried out, and the nitrogen removal efficiency and membrane fouling characteristics after the addition of carbon source were investigated. The main achievements of the research are as follows: (1) the technical strategy of carbon source preparation for food waste is proposed, and the anaerobic digestion process is controlled at the stage of hydrolysis and acidification to achieve the available carbon source. High efficiency recovery. High temperature free fermentation (55 C, no pH regulation) can effectively promote the hydrolysis of organic matter. Carbohydrates are the main products in the products. Medium temperature acid fermentation (37 degree C, intermittent regulation of pH to 6) is beneficial to acidification process and can effectively enrich lactic acid bacteria (Lactobacillus). The products are mainly lactic acid, and the maximum lactic acid yield is obtained when OLR is 14 g-TS/L D. The higher OLR was not beneficial to lactic acid fermentation. (2) the effect of different inoculation on the preparation of carbon source in medium temperature lactic acid fermentation was compared. It was found that the production of lactic acid was the largest and the loss of organic matter was the least. The results of microbial population structure analysis showed that, although the diversity of the microbial population structure in the inoculant was the best, it was the best. Under the condition of fermentation, Lactobacillus can enrich and become the dominant population, and realize the efficient transformation of matrix. (3) the dynamic membrane lactic acid fermentation strengthening technology was put forward, the dynamic membrane was used to intercept the granular organic matter, prolong the residence time of the matrix in the reactor, increase the microbial biomass and strengthen the microbial enzyme activity. The continuous separation of dissolved fermentation products can be achieved by dynamic membrane lactic acid fermentation, and the efficiency of the fermentation carbon source can be improved. (4) the transformation path of "carbohydrate to lactic acid to VFAs" in the process of hydrolysis and acidification of organic matter under the condition of medium temperature acid fermentation, and the phase of its phase, and its phase are revealed. The change rule of the microbial population structure of the microorganism. The denitrification test was carried out by using the unfermented, partially fermented, lactic acid based and VFAs dominant phase products as the carbon source. The results showed that the lactic acid based fermentation products had high denitrification rate and potential, and could complete denitrification when the C/N ratio was greater than 6. The fermentation by lactic acid was the main fermentation. The product was used as a small test SBR carbon source for low C/N ratio to actual sewage treatment. It was found that the reactor can run steadily for a long time, the efficiency of nitrogen removal is obviously improved, the carbon source utilization ability of microorganism is enhanced and the diversity of microbial population is rich. (5) the high temperature free fermentation products are mainly carbon hydrates, but they also have good reaction as the external carbon source. Nitrification promotes the effect, and the granular organic matter which is not fully hydrolyzed in the fermentation broth can also be used for biochemical utilization, and the effect of enhanced denitrification is achieved. The high temperature free fermentation product is used as a supplementary carbon source for the low C/N ratio of the actual wastewater treatment in the pilot A/O-MBR system. The results show that the reactor can run steadily for a long time and the carbon source of microorganism can be used. The increase of microbial population with the ability to degrade dissolved microorganism metabolites (SMP) and complex organic matter increased, the relative abundance of denitrifying bacteria increased and the efficiency of denitrification increased obviously. The microbial extracellular polymer (EPS) in the reactor was not obviously accumulated after the fermentation product was added, and the dissolved organic matter (DOM) was treated along the A/O-MBR system. The process gradually decreased, and some pollutants were trapped by the membrane cake layer. The long-term operation did not lead to irreversible fouling on the membrane surface.
【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】：X799
，
本文编号：2156264
[Abstract]:The loss of carbon source is common and has become an important reason for restricting the efficient denitrification of sewage treatment. Strengthening the denitrification process by adding carbon source is an important way to enhance the efficiency of denitrification. In this paper, the characteristics of two carbon source models for high temperature free fermentation and medium temperature lactic acid fermentation are systematically studied based on the purpose of this purpose. The characteristics of the denitrification characteristics of the fermented products as carbon sources are investigated in this paper. Compared with (C/N) domestic sewage treatment and reuse, the pilot study of A/O-MBR was carried out, and the nitrogen removal efficiency and membrane fouling characteristics after the addition of carbon source were investigated. The main achievements of the research are as follows: (1) the technical strategy of carbon source preparation for food waste is proposed, and the anaerobic digestion process is controlled at the stage of hydrolysis and acidification to achieve the available carbon source. High efficiency recovery. High temperature free fermentation (55 C, no pH regulation) can effectively promote the hydrolysis of organic matter. Carbohydrates are the main products in the products. Medium temperature acid fermentation (37 degree C, intermittent regulation of pH to 6) is beneficial to acidification process and can effectively enrich lactic acid bacteria (Lactobacillus). The products are mainly lactic acid, and the maximum lactic acid yield is obtained when OLR is 14 g-TS/L D. The higher OLR was not beneficial to lactic acid fermentation. (2) the effect of different inoculation on the preparation of carbon source in medium temperature lactic acid fermentation was compared. It was found that the production of lactic acid was the largest and the loss of organic matter was the least. The results of microbial population structure analysis showed that, although the diversity of the microbial population structure in the inoculant was the best, it was the best. Under the condition of fermentation, Lactobacillus can enrich and become the dominant population, and realize the efficient transformation of matrix. (3) the dynamic membrane lactic acid fermentation strengthening technology was put forward, the dynamic membrane was used to intercept the granular organic matter, prolong the residence time of the matrix in the reactor, increase the microbial biomass and strengthen the microbial enzyme activity. The continuous separation of dissolved fermentation products can be achieved by dynamic membrane lactic acid fermentation, and the efficiency of the fermentation carbon source can be improved. (4) the transformation path of "carbohydrate to lactic acid to VFAs" in the process of hydrolysis and acidification of organic matter under the condition of medium temperature acid fermentation, and the phase of its phase, and its phase are revealed. The change rule of the microbial population structure of the microorganism. The denitrification test was carried out by using the unfermented, partially fermented, lactic acid based and VFAs dominant phase products as the carbon source. The results showed that the lactic acid based fermentation products had high denitrification rate and potential, and could complete denitrification when the C/N ratio was greater than 6. The fermentation by lactic acid was the main fermentation. The product was used as a small test SBR carbon source for low C/N ratio to actual sewage treatment. It was found that the reactor can run steadily for a long time, the efficiency of nitrogen removal is obviously improved, the carbon source utilization ability of microorganism is enhanced and the diversity of microbial population is rich. (5) the high temperature free fermentation products are mainly carbon hydrates, but they also have good reaction as the external carbon source. Nitrification promotes the effect, and the granular organic matter which is not fully hydrolyzed in the fermentation broth can also be used for biochemical utilization, and the effect of enhanced denitrification is achieved. The high temperature free fermentation product is used as a supplementary carbon source for the low C/N ratio of the actual wastewater treatment in the pilot A/O-MBR system. The results show that the reactor can run steadily for a long time and the carbon source of microorganism can be used. The increase of microbial population with the ability to degrade dissolved microorganism metabolites (SMP) and complex organic matter increased, the relative abundance of denitrifying bacteria increased and the efficiency of denitrification increased obviously. The microbial extracellular polymer (EPS) in the reactor was not obviously accumulated after the fermentation product was added, and the dissolved organic matter (DOM) was treated along the A/O-MBR system. The process gradually decreased, and some pollutants were trapped by the membrane cake layer. The long-term operation did not lead to irreversible fouling on the membrane surface.
【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】：X799
，
本文编号：2156264
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