微生物电化学系统强化含氨氮有机废水处理的效能与机制

发布时间：2018-06-06 15:58

  本文选题：微生物电化学系统 + 梯级降解　； 参考：《哈尔滨工业大学》2017年博士论文

【摘要】：微生物电化学系统(Microbial electrochemical systems,MESs)是利用产电菌的催化作用将有机物中的化学能直接转化为电能的装置。作为一种兼具废水处理和能源回收的新型水处理技术,MESs在电极材料修饰、反应器构型优化及胞外电子传递机制等方面已取得较大突破。然而,在处理成分复杂的有机废水时,MESs表现出产电性能下降、运行能耗高及碳氮同步去除效果差等问题,限制了其在实际废水处理中的应用。针对以上问题,本论文从提高MESs对复杂有机物的降解效能、降低脱氮系统运行能耗两方面展开研究,构建了可实现废水中碳氮同步去除及净能量回收的微生物电化学系统,并对有机物降解过程与微生物种群的协同作用关系及脱氮机制进行深入探讨,对于建立微生物电化学强化废水处理技术具有重要意义。以提高MESs对复杂有机物的处理效能及产电性能为目的,将连续搅拌釜式反应器(CSTR)与MESs耦合,构建了连续搅拌微生物电化学系统(CSMES)。在四通路的电极组合方式下,当进水有机负荷为12 kg COD/m~3/d时,系统内四个电池的最大功率密度分别为583±9、562±7、533±10和572±6 mW/m2。其COD去除率、甲烷产率及能量回收率分别为87.1±1.1%、1.48±0.15 L/L/d和32.1%,均优于平行运行的对照反应器CSTR。高通量测序结果表明,电流的存在使地杆菌属(Geobacter,14.5%)这种典型的产电菌属选择性富集在CSMES的阳极上,相对复杂的细菌群落结构使其同时含有丰度较高的嗜乙酸产甲烷菌属(52.1%)和嗜氢产甲烷菌属(47.0%),而CSTR以单一的嗜乙酸产甲烷菌属为主(79.1%)。底端全混流搅拌区(CMZ)的厌氧消化与顶端微生物电化学区(MEZ)的产电过程之间的协同作用强化了小分子挥发酸的去除,缓解了发酵产物对产甲烷菌的抑制作用,从而提高了CMZ中产甲烷菌的多样性及活性,强化了CSMES的有机物去除效能并使其能量回收率高于CSTR。以啤酒废水为处理对象,考察CSMES对复杂有机物的降解机制。CSMES底端的CMZ以发生水解酸化反应为主,啤酒废水中79.1±5.6%的可溶性蛋白质和86.6±2.2%的可溶性糖类首先在该区被发酵菌属(Clostridium和Bacteroides,19.7%和5.0%)降解为小分子物质,供产甲烷菌属(Methanosaeta和Methanobacterium,40.3%和38.4%)利用。部分小分子物质及未被降解的蛋白质和糖类等沿着水力方向进入顶端的MEZ进一步被该区的产氢产乙酸菌属(Syntrophobacter,20.8%)及产电菌属(Geobacter,12.4%)利用进行产电,提高出水水质的同时以电能的形式回收了啤酒废水中的能量。CSMES对可溶性蛋白质和糖类等有机物的梯级降解过程是保证其处理复杂有机物时产电性能相对稳定的基础,而以上四类菌群的空间分布结构及协同作用是该梯级降解过程的生物学依据。以降低微生物电化学脱氮系统运行能耗为目的,利用虹吸式排水原理,构建了复氧式生物阴极微生物电化学系统(ABMES)。为了提高生物阴极材料在间歇式复氧过程中对氧气的吸附能力,以PTFE对柱状活性炭(CAC)表面的一侧进行疏水处理,制备疏水型柱状活性炭生物阴极材料(PTFE-coated CAC)。将其应用于ABMES中可获得8.2±0.8 W/m~3的最大功率密度,较未经处理的CAC生物阴极比,提高了39%。PTFE-coated CAC的疏水表面对空气的高亲和力强化了氧气向阴极生物膜内部的传质过程,使其空气捕获率(29.7±0.6 L/m~3)较CAC生物阴极比提高了54±3.8%,从而使其氧还原催化性能优于CAC生物阴极。间歇式复氧状态及饱和溶解氧状态下的阴极内阻分析结果表明,电极表面产电菌较高的氧还原催化活性对PTFE-coated CAC性能的提高也起到一定作用。ABMES通过在阴极室实现同步硝化反硝化作用完成脱氮过程。外阻、COD/N及阴极室进水-排水频率三个因素通过影响阴极氧还原反应、硝化过程及反硝化过程对ABMES的产电性能及脱氮效能产生较大影响。在外阻为5Ω、阴极室进水-排水频率为8 cph的条件下,以ABMES处理一种低碳氮比的实际废水——污泥消化液(COD/N=2.5),其最大功率密度及总氮去除率分别为8.9±0.2 W/m~3和53.2±3.8%。这种间歇式复氧方法所需能耗仅占系统产能的14.3%,避免了脱氮过程中使用高能耗的曝气供氧方式。得失电子平衡分析结果表明,异养反硝化与电化学反硝化过程的共同作用是促使ABMES在低碳氮比条件下获得较高总氮去除率的原因。以CSMES-ABMES组成的串联系统处理含氨氮的有机废水——养猪废水,考察其同步脱氮除碳性能。以聚合氯化铝对养猪废水进行混凝处理,混凝后上清液中COD和SS的浓度分别下降到6745±522 mg/L和2441±185 mg/L。以串联系统处理经混凝沉淀的养猪废水,其中对COD和SS起主要去除作用的为CSMES,而ABMES负责氨氮及总氮的去除。串联系统总的COD、SS、氨氮及总氮的去除率分别为97.7±4.5%、94.4±5.8%、85.1±3.3%及43.8±2.3%,并获得了1.298 kWh/m~3的净能量,在完成碳氮同步去除的同时实现污水能源化,理论上可以实现能量自持。
[Abstract]:Microbial electrochemical systems (MESs) is a device for direct conversion of chemical energy in organic matter into electrical energy by using the catalysis of electric bacteria. As a new water treatment technology with both waste water treatment and energy recovery, MESs is used in the modification of electrode materials, optimization of reactor configuration and the mechanism of exo electron transfer. However, in the treatment of complex organic wastewater, MESs shows a decline in electrical properties, high energy consumption and poor carbon nitrogen removal efficiency, which restricts its application in the treatment of waste water. In this paper, the degradation efficiency of complex organic compounds and reduction of nitrogen removal from the higher MESs are proposed in this paper. The two aspects of the energy consumption of the system are studied, and a microbiological electrochemical system can be constructed to realize the simultaneous removal of carbon and nitrogen in the wastewater and the net energy recovery. The relationship between the organic degradation process and the microbial population and the mechanism of nitrogen removal are discussed. It is important for the establishment of microbiological electrochemical enhanced wastewater treatment technology. In order to improve the efficiency and power production performance of MESs for complex organic matter, the continuous agitating reactor (CSTR) and MESs are coupled to build a continuous stirring microorganism electrochemical system (CSMES). The maximum power of four batteries in the system when the influent organic load is 12 kg COD/m~3/d in the four channel electrode combination mode. The COD removal rate was 583 + 7533 + 10 and 572 + 6 mW/m2. respectively. The methane yield and energy recovery were 87.1 + 1.1%, 1.48 + 0.15 L/L/d and 32.1%, respectively, which were superior to the parallel operating control reactor CSTR. high throughput sequencing results. On the anode of CSMES, the relatively complex bacterial community structure makes it contain more eosinophilic methanogenic bacteria (52.1%) and methanogenic bacteria (47%), while CSTR is dominated by a single eosinophilic methanogenic genus (79.1%). The anaerobic digestion of the bottom end total mixed flow area (CMZ) and the production of the apical microorganism electrochemistry school area (MEZ) The synergistic effect between the electrical processes enhanced the removal of the volatile acid of small molecules, alleviated the inhibitory effect of the fermentation products on methanogenic bacteria, thus enhanced the diversity and activity of methanogens in CMZ, enhanced the removal efficiency of CSMES organic matter and made its energy recovery rate higher than that of CSTR., and investigated the complexity of CSMES to the complex. The degradation mechanism of organic matter at the bottom of.CSMES was mainly hydrolyzed and acidified, and 79.1 + 5.6% of soluble protein and 86.6 + 2.2% soluble sugar in beer wastewater were first degraded to small molecular substances (Clostridium, Bacteroides, 19.7% and 5%) in this area for methanogenic bacteria (Methanosaeta and Methanobacterium). 40.3% and 38.4%) MEZ is used to produce hydrogen producing acetic acid (Syntrophobacter, 20.8%) and producing electric bacteria (Geobacter, 12.4%) by using the partial small molecule material and the non degraded protein and sugar and so on. The effluent water quality is improved and the beer wastewater is recovered in the form of electric energy. The cascade degradation process of energy.CSMES to soluble proteins and carbohydrates is the basis for ensuring the relatively stable electrical performance of the complex organic matter, while the spatial distribution structure and synergy of the four types of bacteria are the biological basis for the cascade degradation process to reduce the operating energy of the microbial electrochemical denitrogenation system. In order to improve the adsorption capacity of oxygen in the process of intermittent reoxygenation, ABMES was constructed with the principle of siphon drainage. In order to improve the adsorption capacity of the cathode material to oxygen during the intermittent reoxygenation process, a hydrophobic columnar activated carbon (P) cathode material (P) was prepared by water treatment on one side of the surface of the columnar activated carbon (CAC). TFE-coated CAC). The maximum power density of 8.2 + 0.8 W/m~3 can be obtained by using it in ABMES. Compared with the untreated CAC Biological Cathode ratio, the high affinity of the hydrophobic surface of 39%.PTFE-coated CAC enhances the mass transfer process of oxygen to the cathode biofilm, and the air capture rate (29.7 + 0.6 L/m~3) is more than the CAC cathode. The ratio of oxygen reduction catalyzed by 54 + 3.8% was improved, and the catalytic performance of oxygen reduction was better than that of the CAC cathode. The results of the intermittent reoxygenation state and the cathodic resistance analysis in the saturated dissolved oxygen state showed that the higher oxygen reduction catalytic activity on the electrode surface also played a role in improving the performance of the PTFE-coated CAC through the cathode chamber. The nitrification and denitrification process has completed the process of denitrification. The three factors of external resistance, COD/N and the frequency of influent drainage of the cathode chamber affect the cathodic oxygen reduction reaction, nitrification process and denitrification process have a great influence on the electric property and denitrification efficiency of ABMES. Under the condition of the external resistance is 5 Omega, the influent water frequency of the cathode chamber is 8 CPH, it is treated with ABMES. The actual wastewater of low carbon and nitrogen ratio, COD/N=2.5, has the maximum power density and total nitrogen removal rate of 8.9 + 0.2 W/m~3 and 53.2 + 3.8%.. The energy consumption of the intermittent reoxygenation method is only 14.3% of the capacity of the system. It avoids the high energy consumption oxygen supply mode in the process of denitrification. The common effect of heterotrophic denitrification and electrochemical denitrification is the reason for ABMES to obtain higher total nitrogen removal rate under the low carbon and nitrogen ratio. The series system composed of CSMES-ABMES is used to treat organic wastewater containing ammonia nitrogen - pig wastewater and investigate its synchronous denitrification and decarbonization energy. The concentration of COD and SS in the supernatant after coagulation was reduced to 6745 + 522 mg/L and 2441 + 185 mg/L. respectively to treat the pig wastewater with coagulation sedimentation in series system. The main removal effect of COD and SS was CSMES, and ABMES was responsible for the removal of ammonia nitrogen and total nitrogen. The total COD, SS, ammonia nitrogen and total nitrogen removal rate of the series system was 97.7, respectively. It is + 4.5%, 94.4 + 5.8%, 85.1 + 3.3% and 43.8 + 2.3%, and the net energy of 1.298 kWh/m~3 is obtained. At the same time, the sewage energy is realized at the same time of carbon and nitrogen removal. The energy self holding can be realized in theory.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X703
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本文编号：1987269