【作者】 王晓玲；

【导师】 尹军；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2010， 博士

【摘要】 随着水体“富营养化”问题的日渐突出,污水排放标准不断提高,污水处理技术逐渐从以单一去除有机物为目的的阶段进入既要去除有机物又要脱氮除磷的深度处理阶段,以控制富营养化为目的的脱氮除磷己成为当今污水处理领域的研究热点之一。反硝化聚磷脱氮是近年来颇受关注的污水生物处理新技术,在污水同步脱氮除磷工艺中实现并强化反硝化除磷既可大幅度节省需氧量又能减少有机碳源、剩余污泥量和反应器的有效容积,这对于提高城市污水尤其是低C/N比值城市污水脱氮除磷的可行性具有重要意义。为促进MUCT工艺的研究发展与实践应用,尤其是充分发挥其适于处理低C/N比污水的优势,本课题以模拟生活污水为处理对象,全面系统地研究了MUCT工艺的缺氧吸磷性能,考察了内循环比与工艺缺氧吸磷效果、缺氧吸磷性能与碳源节省量的关系,并开发利用第二缺氧段硝酸盐氮浓度作为MUCT工艺强化缺氧吸磷性能和优化工艺运行的参数,且研究了该参数与进水C/N比的关系。首次研究了MUCT工艺各反应段DO、pH值以及ORP的沿程典型变化规律,并对ORP能否作为强化MUCT工艺缺氧吸磷性能和优化工艺运行的参数进行了探讨。深入研究了厌氧段和第二缺氧段采用完全混合反应器串联运行的反应器型式分别对MUCT工艺厌氧释磷量、缺氧吸磷量的影响,确定最佳的串联反应器级数。MUCT工艺中去除的大部分COD在厌氧段被聚磷菌转化成PHA,转化率受混合液内循环比γ影响。厌氧段释磷量受混合液内循环比γ的影响,当γ为1.5时,总释磷量最高,为6.89g/d。MUCT工艺的吸磷过程发生在第二缺氧段和好氧段,其中缺氧吸磷量与α密切相关,缺氧吸磷质量分数在α=4时最高,为0.44。经计算可知,MUCT工艺缺氧吸磷与好氧吸磷存在6.8%的差别,且强化缺氧吸磷作用可节省外碳源,当α和γ分别为3和1.5时碳源节省量最高,可节省24.29%的碳源。第二缺氧段硝酸盐氮浓度可作为MUCT工艺优化缺氧吸磷性能的控制参数。该值受进水C/N比的影响,当进水C/N比为5、5.45、6、6.67、7.5、8.57、10、12的条件下,最佳SNO3值分别为2.75、2.5、2.25、2、1.75、1.5、1.25、1,此时缺氧吸磷质量分数可分别达到0.467、0.455、0.44.、0.410、0.365、0.300、0.210、0.100。第二缺氧段ORP与硝酸盐氮浓度之间存在很好的线性相关关系,因此,可用ORP代替最佳硝酸盐氮浓度作为MUCT工艺优化缺氧吸磷性能的控制参数。该参数同样受进水C/N比的影响。当进水C/N比为5、5.45、6、6.67、7.5、8.57、10、12时,最佳ORP分别为-71、-83、-90、-94、-101、-113、-117、-124mV。MUCT工艺厌氧段串联反应器级数越多,厌氧释磷量越多,缺氧吸磷质量分数也随之增加。理论分析和试验结果还表明,当厌氧段串联反应器级数从单级增加至2级(总停留时间相同)时,厌氧段COD去除量及消耗速率、TP释放量及释磷速率等明显增加。所以在本试验条件下,厌氧段串联反应器级数推荐为2级。第二缺氧段串联反应器级数越多,第二缺氧段出水TP浓度越低,缺氧吸磷质量分数越高。在本试验条件下,第二缺氧段串联反应器推荐级数为2级。根据氨氮和硝酸盐氮的物料平衡计算结果,证明了在MUCT工艺中发生着明显的同步硝化反硝化现象。这对于MUCT工艺的实际应用具有很重要的意义。更多还原

【Abstract】 Sewage discharge standard is rising with eutrophication gradually becoming a prominent problem. Sewage disposal technology must remove not only organics but also nitrogen and phosphorus. Nitrogen and phosphorus removal aiming at eutrophication control is a hot problem in the sewage disposal. Denitrifying phosphorus removal has been a new and noticeable biological technology in recent years. It can save oxygen consumption, and reduce original carbon, excess sludge and effective volume of reactors. Hence it plays an important role in increasing the nitrogen and phosphorus removal feasibility of domestic sewage, especially domestic sewage with low C/N ratio.In order to promote the research development and practical application of MUCT process, especially to exert full advantage of domestic sewage with low C/N ratio, the relation between recirculation ratio and anoxic phosphorus uptake were investigated by using simulative domestic sewage in this project. The concentration of NO3--N in the second anoxic zone was settled as a parameter strengthening the anoxic phosphorus uptake capability and optimizing the process, and the relation between the concentration of NO3--N in the second anoxic zone and C/N ratio of influent was also studied. Typical variation rule of DO, pH and ORP in each stage was investigated for the first time. The feasibility of ORP settling as a parameter strengthening the anoxic phosphorus uptake capability and optimizing the process was discussed. The effects of both the anaerobic zones and the second anoxic zone running as a succession of CSTRs on the anaerobic phosphorus release and the anoxic phosphorus uptake were studied respectively. Optimal number of CSTRs in series was determined.Most COD was change into PHA by PAO in anaerobic zones in MUCT process, and the transformation ratio is affected by mixed-liquor return ratio (γ). The anaerobic phosphorus release was influenced byγ. The anaerobic phosphorus release reached the highest level of 6.89g/d whenγwas 1.5. Phosphorus uptake occurred in the second anoxic zone and aerobic zones in MUCT process. The anoxic phosphorus uptake was closely related to reflux ratio of nitrification (α). The anaerobic phosphorus uptake mass fraction reached the maximum of 0.44 whenα was 4. The difference between anoxic phosphorus uptake and aerobic phosphorus uptake was 6.8% after calculation. Additional carbon source could be saved when anoxic phosphorus uptake was strengthened. Whenαwas 3 andγwas 1.5, the maximum of carbon source saving was 24.29%.NO3--N concentration in the second anoxic zone, which was influence by the C/N ratio of influent, could be settled as controls parameter of anoxic phosphorus uptake performance in MUCT process. When C/N ratio were 5, 5.45, 6, 6.67, 7.5, 8.57, 10 and 12, the optimal NO3--N concentration in the second anoxic zone (SNO3) were 2.75, 2.5, 2.25, 2, 1.75, 1.5, 1.25 and 1, respectively, with the anoxic phosphorus uptake mass fraction of 0.467, 0.455, 0.44, 0.410, 0.365, 0.300, 0.210 and 0.100, respectively.There was a linear correlation between ORP and the concentration of NO3--N in the second anoxic zone. Hence ORP, which was also influence by the C/N ratio of influent, could be settled as controls parameter of anoxic phosphorus uptake performance instead of NO3--N concentration in MUCT process. When C/N ratio were 5, 5.45, 6, 6.67, 7.5, 8.57, 10 and 12, the optimal ORP were -71, -83, -90, -94, -101, -113, -117, -124mV, respectively.The more CSTRs in series of the anaerobic zones was, the more the anaerobic phosphorus released, thus the anaerobic phosphorus uptake mass fraction was also increasing in MUCT process. The results showed that COD removal and consumption speed, TP release and phosphorus release speed were increased obviously when the number of CSTRs in series increased from 1 to 2 under the same total HRT. The recommended number of CSTRs in series of the anaerobic zones was 2 under the conditions of this experiment. The more CSTRs in series of the second anoxic zone was, the lower TP concentration in effluent of the second anoxic zone was, thus the anoxic phosphorus uptake mass fraction was also increasing evidently. The recommended number of CSTRs in series of the second anoxic zone was 2 under the conditions of this experiment.The mass balance computing results of NH4+-N and NO3--N proved a distinct Simultaneous Nitrification and Denitrification (SND) phenomenon in MUCT process, which played an important role in practical application of MUCT process.更多还原