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好氧颗粒污泥及颗粒化动态膜生物反应器的研究
Study on Aerobic Granular Sludge and Granular Sludge Dynamic Membrane Bioreactor
【作者】 刘宏波;
【导师】 杨昌柱;
【作者基本信息】 华中科技大学 , 环境工程, 2009, 博士
【摘要】 好氧颗粒污泥技术是目前最有发展前景的污水处理工艺之一,具有沉降性能好、有机负荷高、同步硝化反硝化能力强、生物除磷效果好等优点,但它存在系统不稳定、出水浊度波动大的不足。本研究在SBR反应器内,对好氧颗粒污泥的低温培养、生物相分布和稳定性等方面进行了试验研究;并以此为基础,将好氧颗粒污泥工艺与膜分离技术相结合,拟开发出一套稳定、高效的可持续污水处理工艺。主要研究成果包括:(1)GSBR反应器中好氧颗粒污泥特征的研究在低温条件下,好氧颗粒污泥能够在SBR反应器快速的培养成功,并实现稳定的运行,同时表现出沉降性能好、EPS含量高和有机物去除速率大、丝状菌生长旺盛等特点。在常温条件下,停运闲置对好氧颗粒污泥的影响不大,且颗粒污泥恢复速度快;但进水氨氮浓度和COD浓度对好氧颗粒污泥的影响较大。酵母菌和霉菌是好氧颗粒中的主要微生物种群,而细菌和放线菌也是其重要的组成部分之一。在单一好氧条件下,颗粒化SBR反应器对TP的去除是通过“富营养释磷”和“贫营养吸磷”实现的。(2)SBGDMBR反应器的研究试验在高氨氮、偏碱性条件下,成功地培养出了在高氨氮条件下能稳定生存、硝化反硝化能力强的好氧颗粒污泥,并将其接种到序批式动态膜生物反应器中,构成了SBGDMBR。试验结果表明,SBGDMBR反应器具有良好的处理高氨氮、低C/N污水效果。且当膜通量为普通动态膜反应器膜通量的5-30倍时,动态膜能够稳定运行20多天,不用进行膜清洗,分离效果良好。试验采用高压水冲洗的方式对被污染动态膜进行恢复性清洗,膜通量能够100%的恢复。试验还研究了动态膜在超高膜通量下的过滤特征,分析了膜出水规律以及排泥频率和出水方式对SBGDMBR的影响。(3)CFGDMBR反应器的研究试验以粒径选择压法成功地培养出了适应于连续流运行模式的好氧颗粒污泥,并将其接种到新型的连续流动态膜生物反应器中,构成了CFGDMBR反应器。试验结果表明,好氧颗粒污泥能够在CFGDMBR反应器内稳定存在,但粒径小、沉降性较差、结构松散和丝状菌生长旺盛。在70多天的运行期间,CFGDMBR反应器表现出良好的有机物和氨氮去除效果,COD和NH4+-N的去除率分别85%和75%左右;具有一定的反硝化和好氧除磷去除效果,TN和TP的去除率分别为67%和58%左右。同时,系统表现出较好的稳定性,有较强的抗水力负荷冲击和有机负荷冲击的能力;动态膜膜阻力小、运行周期长。最后还建立了动态膜的形成与污染的机理,提供了动态膜膜面最佳错流流速和最佳清洗曝气量的计算方法
【Abstract】 Aerobic granulation is a promising technology that has great potential in the wastewater treatment due to the advantages of excellent biomass settleability, highly organic loading rate, simultaneous nitrification and denitrification and biological phosphorus removal. However, the effluents of the granular sludge reactors are often not stable, resulting from the washout of mixed liquor suspended solids (MLSS). Therefore, firstly, in the SBR, the cultivating method at low temperature, main microorganism and stability of aerobic granules were studied. Then, based on the research results, aerobic granulation technology was combined with the membrane bioreactor for developing a sustainable technology of low energy consumption, low investment cost, low running cost and high efficiency. This paper includes following research works:(1) Characteristics of aerobic granular sludge in the GSBRAt low temperature, aerobic granules could be cultivated quickly in SBR. And the cultivated aerobic granules dominated by filamentous have good settleability, high content of extracellular polymeric substances (EPS), and good removal efficiency of organic matters. At normal temperature, the influences of operation disruption and ammonia and COD concentrations in influent on aerobic granules were studied, the main microorganism in granules was isolated and cultured, and mechanism of phosphorus removal in the sole aerobic condition was analyzed. It indicated that aerobic granules could be slightly influenced by operation disruption, but could be seriously influenced by ammonia and COD concentrations in influent. Yeast and mould were found to be the main microorganism. Finally, a two-stage mechanism of phosphorus removal was simulated in the granular SBR and then testified systematically.(2) Characteristics of SBGDMBRUnder alkalescent and high ammonia concentration environment, aerobic granules with highly nitrification and denitrification potential and accommodating to high ammonia concentration were successfully cultivated. Then, the SBGDMBR was developed by seeding this kind of aerobic granules in the SBDMBR. Results showed that SBGDMBR had great ability in disposing cesspool wastewater. And when the membrane flux was 5-30 times of that in the common DMBR, dynamic membrane could operate normally more than 20 days without membrane cleaning, and membrane flux could be 100% recovered by the washing of high pressure water. Moreover, the influences of sludge discharging frequency and effluent discharging mode on SBGDMBRR were studied.(3) Characteristics of CFGDMBRAerobic granular sludge accommodating to continuous-flow mode was successfully cultivated under the selective pressure of granule size in SBR. And a novel continuous-flow granular dynamical membrane bioreactor (CFGDMBR) was developed by seeding this kind of aerobic granules into the continuous-flow dynamical membrane bioreactor. The aerobic granules existing stably in the CFGDMBR had the characteristics of small particle size, bad settleability, loose structure and high water content.During the operation period of more than 70 days, CFGDMBR presented good organic and ammonia removal capabilities, 85% and 75%, respectively. Moreover, when DO was about 3.0-6.0 mg/L, CFGDMBR had TN and TP removal rates of 67% and 58%, respectively. Furthermore, the CFGDMBR system presented the characteristics of stability, strong anti-shocking of organic and hydraulic loading, low membrane resistance and long operation cycle. At last, the mechanisms of formation and fouling of dynamic membrane was built, and the methods for calculating the optimum cross-flow rate on the membrane surface and aeration gas amount for controlling membrane fouling were provided.
【Key words】 Aerobic granular sludge; dynamic membrane bioreactor; Super-high membrane flux; Continuous flow;