潮汐式生物接触氧化法处理生活污水试验研究

发布时间：2018-05-19 04:01

本文选题：潮汐式 + 生物接触氧化　；参考：《兰州交通大学》2017年硕士论文

【摘要】：随着我国城镇化建设的快速发展,城镇居民生活水平不断提高,产生的生活污水量越来越大。对城市污水收集管网未遍及区域和农村地区的分散式生活污水进行就地处理,已成为控制水体污染的重要途径。因此,在选择分散式污水处理技术时既要因地制宜,选择适合当地环境条件的技术,又要兼顾经济、技术合理性,选择出水水质稳定,操作管理简单、投资、运行费用低的技术。兼具活性污泥法与生物膜法二者优点的生物接触氧化工艺,被广泛用于处理分散式生活污水,但是其在运行过程中存在曝气布水不均匀,容易出现死角的问题。基于分散式生活污水处理工艺要求及生物接触氧化工艺存在的不足,本文提出了潮汐式生物接触氧化,采用“快速进水-淹没-快速排水-空置”的潮汐式运行方式处理生活污水。其中,快速进水相当于“涨潮”过程,使污水流经填料;淹没阶段污水与填料充分接触,有机物吸附于生物膜;快速排水相当于“退潮”过程,形成抽吸作用将空气快速吸入反应器中,为生物膜上微生物好氧降解污染物提供氧气;空置阶段微生物以被生物膜吸附有机物为底物,借助抽吸复氧供给的氧气进行高效降解,同时反应器中形成的溶解氧浓度差也强化了氧的自然扩散。潮汐过程中,排水后填料孔隙均被吸入空气充满,使氧气在反应器里均匀分布,再次进水时排挤出填料孔隙内空气使污水与生物膜充分接触,不留死角。潮汐过程提高了生物接触氧化反应器的氧传输量和复氧能力,克服了传统生物接触氧化工艺布水、曝气不易均匀,局部有死角的问题。运行过程中无需曝气系统,仅需消耗少量动力实现潮汐,属于低成本运行工艺,可以有效降低运行费用。试验采用城市污泥再生填料,该填料具有孔隙率高、表面粗糙、易于附着生物膜的特点,既满足了生物接触氧化法填料应满足的要求,又实现了城市污泥的再生利用。论文主要研究内容与结论如下:(1)采用自然挂膜法启动潮汐式生物接触氧化,在环境温度15～21℃左右,DO2mg/L以上,淹没空置时间比为1:3的条件下,挂膜15天后,COD_(cr)去除率稳定在80%以上;到29天,氨氮去除率达到91.9%。此时,系统对COD_(cr)、氨氮去除效果稳定,标志着挂膜成功,表明以城市污泥再生填料为载体的潮汐式生物接触氧化反应器在较低温度下可以实现较快挂膜启动。(2)本试验研究了不同运行条件潮汐式生物接触氧化对生活污水中有机物的去除效果,结果表明在进水水质波动大的情况下,出水水质稳定,对污水中COD_(cr)处理效率高,表明系统抗冲击负荷能力强。通过考察不同运行条件的潮汐式生物接触氧化对生活污水中有机物去除效果,对比分析不同淹没空置时间比、处理时间对处理效果的影响。试验结果表明较大的淹没空置时间比更有利于有机物去除,原因是潮汐次数相同时较大的淹没空置时间比对应的淹没时间较长,从而强化了淹没时生物膜对污染物的吸附,使吸附更加充分;不同处理时间的试验结果表明,反应器中COD_(cr)的降解主要发生在处理周期的前段,后段以生物膜的更新再生为主,根据处理水质选择适当的处理时间既能满足去除COD_(cr)的要求,又可以使生物膜充分再生,从而有利于下一周期的吸附,使该工艺整体处理效果较好。(3)为实现去除有机物的同时脱氮的目的,本试验在潮汐式生物接触氧化反应器中设置了潮汐区、淹没区为脱氮提供条件,试验结果表明,对氨氮的去除效果较好,6种运行条件平均去除率在72%以上,最高可达99.4%。试验过程中硝氮积累量明显低于氨氮去除量,表明在去除氨氮的同时存在N损失,说明反应器中发生了同步硝化反硝化。对比不同淹没空置时间比的氨氮效果发现较大的淹没空置时间比有利于去除氨氮;温度低于15℃时,对硝化反应有明显的抑制,氨氮去除效果仅为72.4%(C2段)。生物膜硝化、反硝化强度实验表明反应器上部潮汐区为硝化区,反应器中无明显反硝化区。由潮汐式生物接触氧化处理生活污水去除COD_(cr)、氨氮试验结果可知在进水COD_(cr)为175.9～386.8 mg/L、氨氮为34.2～51.6 mg/L时选择淹没空置时间比为1:1,处理时间为24h的运行条件C1,可以获得较好的COD_(cr)去除效果,同时氨氮去除效果也较好。(4)对反应器生物膜特性进行研究,从微生物角度揭示潮汐式生物接触氧化的去除机理。显微镜观察潮汐式生物接触氧化生物膜,发现大量菌胶团及多种原、后生动物及微型动物,说明生物膜微生物相丰富。生物膜上多种细菌、原、后生动物等微生物间存在稳定的捕食-被捕食关系,维系了较长的食物链。(5)通过测定挥发性生物膜量及生物膜微生物呼吸速率确定了潮汐式生物接触氧化反应器生物膜量及膜活性,生物膜量折算成MLSS达18.01g/L,高于传统生物接触氧化;呼吸速率为40.2kgCO2/kg活性生物膜·d,表明反应器内生物膜量大且膜活性高。(6)本试验采用Biolog-ECO方法对潮汐式生物接触氧化反应器长期运行过程中生物膜微生物碳源代谢特征进行分析,进一步解析潮汐式生物接触氧化净化机理。试验结果表明潮汐式生物接触氧化反应器中生物膜微生物对应的易利用碳源与生活污水中碳源组成基本一致,正是由于微生物生存环境中丰富的易利用碳源使生物膜微生物快速生长繁殖,且群落多样、物种丰富。
[Abstract]:With the rapid development of urbanization in China, the living standard of urban residents is increasing and the amount of domestic sewage is becoming more and more large. The treatment of scattered domestic sewage from the urban sewage collection pipe network which has not spread throughout the region and rural areas has become an important way to control the pollution of the water body. Therefore, the choice of decentralized sewage treatment is chosen. The technology not only should be adapted to local conditions, but also choose the technology suitable for the local environment conditions, but also take into account the economic and technical rationality, and choose the technology of stable water quality, simple operation and management, investment and low operating cost. The biological contact oxidation process with the advantages of the active sludge process and the biofilm method is widely used in the treatment of dispersed domestic sewage. However, in the course of operation, there is an uneven distribution of aeration water and the problem of dead angle. Based on the requirements of the treatment process of dispersed domestic sewage and the deficiency of the biological contact oxidation process, this paper puts forward the tidal biological contact oxidation, and uses the "fast influent submerged fast drainage empty" tidal operation mode. The rapid influent is equivalent to the "flood tide" process, which makes the sewage flow through the packing; the sewage and the filler are fully exposed in the submerged stage, and the organic matter is adsorbed on the biofilm; the rapid drainage is equivalent to the "ebb tide" process, forming the suction in the air fast inhalation reactor to provide oxygen for the aerobic degradation pollutants on the biofilm; In the vacancy stage, the microorganism is used as the substrate for the adsorption of organic matter by the biofilm, and the oxygen is degraded efficiently with the oxygen supplied by the suction and reoxygenation. At the same time, the difference of dissolved oxygen in the reactor also strengthens the natural diffusion of oxygen. In the tide process, the pore of the packing is filled with air, so that the oxygen is evenly distributed in the reactor and reentered into the reactor. In the water, the air is extruded in the pore air to make the sewage fully contact with the biofilm without leaving the dead angle. The tide process improves the oxygen transfer and reoxygenation capacity of the biological contact oxidation reactor, overcomes the problem of the traditional biological contact oxidation process, is not easy to be evenly aerated and has a local dead angle. No aeration system is needed during the operation process, and only need to be consumed. A small amount of power to realize the tide, which belongs to the low cost operation process, can effectively reduce the operating cost. The experiment adopts the urban sludge regenerating packing, which has the characteristics of high porosity, rough surface and easy attachment to biological membrane, which not only satisfies the requirements of the biological contact oxidation method, but also realizes the regeneration and utilization of the municipal sludge. The main research contents and conclusions are as follows: (1) using the natural membrane method to start the tidal biological contact oxidation, the removal rate of COD_ (CR) is stable over 80% at the ambient temperature of about 15~21 degrees C, DO2mg/L above and the vacancy time ratio of 1:3, and the removal rate of ammonia nitrogen reaches 91.9%. at the 29 day, and COD_ (CR), ammonia nitrogen goes to the system. In addition, the effect is stable, indicating the success of the film hanging. It shows that the tidal biological contact oxidation reactor which takes the regenerated sludge as the carrier of the municipal sludge can realize the rapid film starting at a lower temperature. (2) the effect of the removal of organic matter in the polluted water by the tidal biological contact oxidation in different operating conditions is studied in this experiment. The results show that the influent is in the water. Under the condition of high water quality, the water quality is stable and the treatment efficiency of COD_ (CR) in sewage is high, which indicates that the system has a strong ability to resist impact load. By investigating the removal efficiency of organic matter in domestic sewage by observing the different operating conditions, the effects of different submergence time ratio and treatment time on the treatment effect are compared and analyzed. The test results show that the larger inundation time is more beneficial to the removal of organic matter, the reason is that the larger inundation time is longer than the corresponding submerged time when the times of the tide are the same, thus strengthening the adsorption of pollutants in the submerged biofilm and making the adsorption more sufficient; the experimental results of different treatment time show that the COD_ (c) in the reactor has been shown. The degradation of R mainly occurs in the front of the treatment cycle, the latter is mainly the regeneration and regeneration of the biofilm. According to the treatment time, the appropriate treatment time can not only satisfy the requirement of removing COD_ (CR), but also make the biofilm fully regenerated, thus it is beneficial to the adsorption of the next cycle, and the whole treatment effect is better. (3) the removal is achieved. For the purpose of simultaneous denitrification of the machine, the tidal zone was set in the tidal biological contact oxidation reactor. The submerged area was the condition of nitrogen removal. The experimental results showed that the removal efficiency of ammonia nitrogen was better. The average removal rate of 6 operating conditions was above 72% and the maximum was up to 99.4%. The accumulation of nitrate and nitrogen in the test process was obviously lower than the ammonia nitrogen removal. It shows that there is N loss in the removal of ammonia nitrogen at the same time, indicating that synchronous nitrification and denitrification occurs in the reactor. The effect of ammonia nitrogen on different submergence time ratio is found to be better than ammonia nitrogen. When the temperature is lower than 15, the nitrification reaction is obviously inhibited and the removal efficiency of ammonia nitrogen is only 72.4% (C2 section). The experiment of nitrification and denitrification showed that the tidal zone in the upper part of the reactor was nitrification area, and there was no obvious denitrification zone in the reactor. COD_ (CR) was removed by tidal biological contact oxidation treatment. The results of ammonia nitrogen test showed that the influent COD_ (CR) was 175.9 ~ 386.8 mg/L, and when ammonia nitrogen was 34.2 ~ 51.6 mg/L, the choice of submergence vacancy time was 1:1, The removal efficiency of COD_ (CR) can be obtained with a running condition of 24h (C1), and the removal efficiency of ammonia nitrogen is also better. (4) the biological membrane characteristics of the reactor are studied. The removal mechanism of tidal biological contact oxidation is revealed from the microbiological angle. A variety of original, metazoan and microanimals, indicating that biofilm is rich in microbial phase. There are stable predator-prey relationships among a variety of bacteria, probiotic, metazoan and other microorganisms on the biofilm. (5) tidal biological contact oxidation is determined by determining the amount of volatile biofilm and the rate of biofilm respiration. The biomass and membrane activity of the reactor were converted to MLSS up to 18.01g/L, which was higher than that of the traditional biological contact oxidation. The respiration rate was 40.2kgCO2/kg active biofilm. D, indicating that the biofilm was large and the membrane activity was high in the reactor. (6) the Biolog-ECO method was used in the long-term operation of the biological contact oxidation reactor of the tidal type. The characteristics of carbon source metabolism of membrane microorganism were analyzed, and the mechanism of biological contact oxidation purification was further analyzed. The experimental results showed that the carbon source corresponding to biofilm microorganisms in the biological contact oxidation reactor was basically consistent with the carbon source in domestic sewage, and it was the abundant easy to use carbon in the living environment of the microorganism. The source makes the biofilm microorganism grow rapidly and propagate, and the community is diverse, the species is rich.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X799.3

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