基于自养反硝化工艺处理低有机碳水中硝酸盐技术研究

发布时间：2018-05-31 08:43

本文选题：硝酸盐 + 电极强化生物膜　；参考：《中国地质大学(北京)》2017年博士论文

【摘要】：硝酸盐(NO_3~-)是陆地生态系统中最常见的污染物之一,随着社会的发展和城市化进程的加速,NO_3~-污染已成为地表水和地下水生态系统中一个严重的环境问题。为了使生物反硝化方法更有效地应用于低有机碳水的NO_3~-去除过程中,在前人对自养反硝化技术研究的基础上,本研究针对低有机碳源的地下水及硝化生活污水,分别开发出适用的电极强化生物膜自养-异养协同反硝化方法和硫铁矿颗粒自养反硝化方法,为低有机碳水的生物脱氮提供了新途径。本研究首先构建电极强化生物膜自养-异养协同反硝化反应器(BER-AHD),分别在固定和变化C/N条件下确定反应所需最佳电流密度,并利用中心组合设计(CCD)和响应曲面法分析(RSM),确定反应器的最适C/N和电流密度分别为1.13和239.6 mA/m2,且在该条件下NO_3~--N去除率可达到100%。在此基础上,利用最大可能数计数(MPN)方法,确定反应器内自养和异养反硝化细菌的含量分别为2.0×103和2.0×105个/mL;并通过分析溶解态CO2及COD浓度,证明反应器内自养与异养反硝化菌具有协同关系,即异养反硝化过程产生的CO2,可以用作自养反硝化过程的无机碳源,且CO2的利用又促进了异养反硝化的进行。相比于传统的电极生物膜技术,本研究不仅可提高去效率、减少有机碳源添加量,而且能够有效地提高氢气利用率,降低能耗。由于BER-AHD阳极易腐蚀,且处理后出水中含有一定量的NH4+-N,故而该工艺较适用于低有机碳的地下水NO_3~-处理,并不适用于含有残留NH4+的硝化生活污水的处理,因此,针对硝化生活污水的处理问题,本研究通过微生物培养驯化批实验,确定硫铁矿颗粒自养反硝化(PPAD)的反硝化速率为0.86 mg/(L·h),低于单质硫氧化反硝化(SOD)速率1.19 mg/(L·h)。在此基础上,构建上流式固定床反应器对PPAD和SOD性能进行对比研究,结果表明,在空床接触时间(EBCT)为2.9 h时,平均NO_3~--N去除率分别为39.7%和99.9%;虽然本研究中PPAD柱的反硝化速率较低,但碱度消耗和副产物生成量均低于SOD,具有很好的应用潜力。进而,本研究采用模拟实际硝化生活污水,通过批实验和柱实验对PPAD进行性能优化研究。批实验结果表明,PPAD培养瓶在硫铁矿投加量125 g/L、生物质浓度(VSS)1250 mg/L、硫铁矿颗粒粒径0.815~1.015mm时,反硝化速率常数k最高,达到0.473 d-1。上流式固定床反应器(柱实验)研究结果显示,在反应器EBCT为5.8 h时,硫铁矿颗粒、石英砂和牡蛎壳(P+S+OS)填充柱的总无机氮(TIN)去除率为89.7%,而硫铁矿颗粒和石英砂(P+S)填充柱为70.1%,证明牡蛎壳的添加有助于PPAD脱氮性能的提升,同时对副产物的分析得知,混合营养型反硝化是导致P+S+OS填充柱高TIN去除率的主要原因。本研究所开发的BER-AHD与PPAD生物脱氮技术,可适用于不同低有机碳水中NO_3~-处理,并提出了利用以自养生物反硝化技术为基础的组合工艺处理不同污染水中NO_3~-的新思路。
[Abstract]:With the development of society and the acceleration of urbanization, the pollution has become a serious environmental problem in the surface water and groundwater ecosystem. In order to make the biological denitrification method more effective in the process of NO3C removal of low organic carbon water, based on the previous researches on autotrophic denitrification technology, this study was aimed at the groundwater and nitrified domestic sewage from low organic carbon source. The methods of electrode enhanced biofilm autotrophic and heterotrophic synergistic denitrification and pyrite particle autotrophic denitrification have been developed respectively which provide a new way for biological denitrification of low organic carbon water. In this study, the electrode enhanced biofilm autotrophic and heterotrophic synergistic denitrification reactor (BER-AHDN) was constructed, and the optimum current density for the reaction was determined under the condition of fixation and variation of C / N, respectively. The optimum C / N and current density of the reactor were 1.13 and 239.6 Ma / m ~ (2), respectively, and the removal rate of NO_3~--N could reach 100% under these conditions. On the basis of this, the contents of autotrophic denitrifying bacteria and heterotrophic denitrifying bacteria were determined to be 2.0 脳 10 ~ 3 and 2.0 脳 10 ~ 5 / mL, respectively, and the concentrations of dissolved CO2 and COD were analyzed by the method of maximum possible number counting (MPN). The results showed that autotrophic and heterotrophic denitrifying bacteria had a synergistic relationship, that is, CO _ 2 produced by heterotrophic denitrification process could be used as inorganic carbon source in autotrophic denitrification process, and the utilization of CO2 promoted heterotrophic denitrification. Compared with the traditional electrode biofilm technology, this study can not only improve the removal efficiency, reduce the amount of organic carbon source, but also effectively improve the hydrogen utilization rate and reduce energy consumption. Because the BER-AHD anode is easy to corrode and there is a certain amount of NH4 -N in the effluent after treatment, the process is more suitable for the treatment of low organic carbon groundwater NOS3, and is not suitable for the treatment of nitrified domestic sewage containing residual NH4. According to the treatment of nitrified domestic sewage, the experiment of microbial culture and acclimation showed that the denitrification rate of pyrite particle autotrophic denitrification (PPAD) was 0.86 mg/(L / h, which was lower than that of elemental sulfur oxidation denitrification (SOD) rate of 1.19 mg/(L / h. On this basis, the upflow fixed-bed reactor was constructed to compare the performance of PPAD and SOD. The results showed that the average removal rate of NO_3~--N was 39.7% and 99.9%, respectively, when the empty bed contact time was 2.9 h, although the denitrification rate of PPAD column was lower in this study. However, alkalinity consumption and by-product production are lower than SOD, which has good application potential. Furthermore, the performance of PPAD was optimized by batch experiment and column experiment. The results of batch experiment showed that the denitrification rate constant k was the highest at 0.473 d ~ (-1), when the dosage of pyrite was 125g / L, the concentration of biomass was 1250mg / L, and the particle size of pyrite was 0.815~1.015mm. The results of upflow fixed-bed reactor (column experiment) showed that when the EBCT of the reactor was 5.8 h, the pyrite particles could be obtained. The removal rate of total inorganic nitrogen was 89.7 for quartz sand and oyster shell PS filled column, and 70.1 for pyrite particle and quartzite sand filled column. It is proved that the addition of oyster shell can improve the nitrogen removal performance of PPAD, and the by-product analysis shows that the addition of oyster shell can improve the denitrification performance of Oyster Shell. Mixed nutrient denitrification is the main cause of high TIN removal rate in P S OS filled column. The biological denitrification technology of BER-AHD and PPAD developed in this paper can be applied to the treatment of NO3- in different low organic carbon water, and a new idea of treating NO3- in different polluted water by the combined process based on autotrophic biological denitrification is put forward.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X703

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