【作者】 杨群；

【导师】 杨昌柱；

【作者基本信息】 华中科技大学 ， 环境工程， 2011， 博士

【摘要】 本研究将膜生物反应器(MBR)和电极-生物膜反应器(Biofilm-electrode Reactor, BER)技术相结合,形成适用于低C/N比污水脱氮处理的电化学-物化-生化组合脱氮工艺——EMBR (Electrode-membrane Biological Reactor)反应器。利用自制的小型EMBR试验装置进行了低C/N比化粪池污水脱氮工艺试验,对自制EMBR反应器的工艺性能、生物-电化学特性、脱氮机理及其脱氮过程的数学模式进行了系统研究。课题研究内容及取得的主要成果如下：(1)利用自制的复合式活性炭纤维BER反应器对低C/N比污水进行了强化脱氮的试验。结果表明：当进水有机物浓度和C/N较低时,反应器具有较为明显的强化脱氮作用。当C/N小于3.0时,BER的脱氮效率与C/N基本成正相关；在进水C/N比、有机物浓度和反应器电流密度适宜的条件下,BER的脱氮效率与单纯生物膜反应器相比可提高6-15个百分点；保持C/N不变,提高进水污染物浓度会导致所需电流密度的提高和脱氮效率的下降。(2)将自制的活性炭纤维生物膜电极引入A/O型MBR,形成EMBR工艺体系,利用正交试验确定了试验装置处理低C/N比化粪池污水的最佳工艺参数,在此基础上进行了工艺效能试验。结果表明：EMBR具有与MBR类似的污染物高效去除特征,在进水COD平均浓度为138mg/L,COD/TN≈3和最佳工艺参数条件下,EMBR系统对进水中的浊度、COD、NH4+-N和TN的平均去除率可分别达到96.4%,93.1%,84.5%和62.3%,出水可满足回用水水质要求。联合反硝化室在TN去除过程中起着重要作用,其TN去除率约为9.1%。与MBR系统相比,EMBR的TN去除率可提高7.3%左右。EMBR反应器具有较强的抗COD冲击负荷的能力,但对NH4+-N冲击负荷的变化较为敏感。(3)在EMBR系统内部,电化学反应是实现生物强化脱氮的前提和条件,生物化学反应是电化学反应产物发挥作用的必要途径。电化学反应过程和生物化学反应过程之间相互作用、相互影响,形成特定的生物-电化学耦合作用体系,共同促进工艺系统脱氮能力的提高。在EMBR系统的联合反硝化室内,反应器电流密度的变化对生物脱氮过程的TN最大比降解速率有显著的影响。在试验进水水质和工艺参数条件下,EMBR系统内TN最大比降解速率发生在电流密度为0.03mA/cm2时。在电流密度过大时,联合反硝化室内有类似“氢抑制效应”现象发生。在电流密度适宜,电极生物膜活性较高的条件下,脱氮微生物的反硝化能力越高,对H的利用能力越强,电化学反应速度提高幅度越大。(4)在EMBR工艺体系中,废水的脱氮依赖四种生化反应过程而进行,即氨化反应,硝化反应,异养反硝化反应和自养反硝化反应。氨化反应和硝化反应主要在EMBR的好氧曝气室内进行；异养反硝化反应主要发生在EMBR前端的异养反硝化室内,是EMBR反应器脱氮的主要途径。在EMBR的联合反硝化室内,有自养-异养联合反硝化反应发生。自养-异养联合反硝化反应的发生是EMBR的重要工艺特征。将联合反硝化室内电极生物膜和悬浮型污泥联合脱氮的过程看成一个整体,结合联合反硝化室的构造特征和工艺条件可建立异养-自养联合反硝化过程的半理论半经验模型如下：N=KN·lambertw(1/KN·exp(-MLSS·(9.12j+0.465)/KN·t-MLSS·(9.12j+0.465)/KN·C1))更多还原

【Abstract】 In this thesis, MBR(Membrane Biological Reactor) technology and BER (Biofilm-electrode Reactor) technology were intergrated to produce a new kind of electrochemical-physicochemical-biochemical denitrogenation process, which is named EMBR(Electrode-Membrane Biological Reactor). Experiments were carried out to dispose the organic wastewater of low C/N ratio from the septic-tank in self-made EMBR experimental device. Technological propoties, biochemical characteristics, denitrifying mechAnism and the denitrification mathematic pattern of EMBR were systematically studied.The contents and the main achievements of this research include:(1) Denitrifying experiments were carried out with simulated wastewater of low C/N ratio in self-made activated carbon fiber electrode-biofilm experimental device. According to the experiment results, the experimental BER system could evidently strengthen the denitrification process with low C/N ratio and low consentration of the organics of the influents. As the C/N ratio was less than 3.0, the denitrifying efficiency increased with the enhance of the C/N ratio. With appropriate influent C/N ratio, organic concentration and working current density, the denitrification efficiency of the experimental BER could be 6 to 15 percents higher than that of simple biofilm reactor. With the invariable influent C/N ratio, the increase of the concentrations of the influent pollutants would accordingly lead to the increase of the optimum current density of the device, while the denitrification efficiency would decrease simultaneously.(2) Self-made activated carbon fiber electrodes were installed in a A/O-MBR to form a experimental EMBR system. An orthogonal experiment was conducted with septic wastewater of low C/N ratio to acquire the optimum working parameters of the experimental EMBR. The technological experiments were carried out to remove the pollutants from the influents afterwards. The experimental results showed that EMBR had similar characteristics of high removal efficiency to MBR. On the optimum technological conditions and with the influent COD concentration of 130mg/L and the C/N ratio of 3.0, the average removal efficiency of the turbidity, COD, NH4+-N and TN of the influents of the experimental EMBR were respectively 96.4%,93.1%,84.5% and 62.3%, and the average concentrations of the turbidity, COD, NH4-N and TN of the efflents were respectively 3.5NTU,8.8mg/L,4.2mg/L and 14.6mg/L, which could successfully meet the quality requirements of water reuse. The multiple denitrifying chamber played an important role in the denitrifying process, with the total nitrogen removal efficiency of 9.1%. The denitrification process in EMBR and MBR was contrasted and discussed by experiments. The TN removing effiency of EMBR was 7.3 % higher than that of MBR. Meanwhile, the experimental EMBR had the same ability of resisting the impact load of COD as MBR, whereras the impact of the NH4+-N loading would apparently decrease the denitrifying efficiency of device, and a interval of about 2 weeks would be necessary for the resume of the denitrifying function of EMBR.(3) In the internal of EMBR, electrochemical reaction was the premise of strengthened denitrification, and biochemical reaction was the necessary pathway for electrochemical reaction of denitrification. The interaction and the influence between electrochemical reaction and biochemical reaction existed to form specific biological-chemical coupling system to promote the denitrifying capability of the technology system. In the multiple denitrifying chamber of EMBR, the change of current density influenced degradation rate of TN significantly. With experimental water quality of the effluents and the operating parameters, the maximum degradation rate of TN occurred at the current density of 0.03 mA/cm2.When current density was excessive, "Hytrogen Inhibition" emerged analogously. With appropriate current density and higher activity of electrode-biofilms, the stronger the denitrifying capability and the hytrogen utilization of the microbes were, the faster the electrochemical reaction proceeded.(4) In technology system of EMBR, denitrification processes relyed on four kinds of biochemical reactions, which were known as amination, nitration, heterotrophic denitrification and autotrophic denitrification. Amination and nitration occurred mainly in aeration chamber. Heterotrophic denitrification played an important role in denitrogenation process and occurred mainly in the front heterotrophic denitrification chamber of the reactor. Heterotrophic-autotrophic mutiple denitrification took placed in the multiple denitrifying chamber of EMBR, which was the main characteristics of the process. Integrating the denitrification of electrode-biofilms and the suspended sludge, with the specific structure of the mutiple denitrifying chamber and the working conditions of EMBR, an empirical model of heterotrophic-autotrophic mutiple denitrification was constructed as follows:N= KN·lambertw(1/KN·exp(-MLSS·(9.12j+0.465)/KN·t-MLSS·(9.12j+0.465)/KN·Cl))更多还原