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一体式好氧膜生物法处理城市垃圾渗滤液的试验研究

The Experimental Study on Treatment of Municipal Landfill Leachate by a Submerged Membrane Bioreactor

【作者】 崔喜勤

【导师】 金奇庭;

【作者基本信息】 西安建筑科技大学 , 环境工程, 2004, 硕士

【摘要】 垃圾渗滤液是垃圾卫生填埋过程中产生的一种难处理的高浓度有机废水,其特点是水质水量波动大、成份复杂、有毒有害物质含量高。目前垃圾渗滤液对周围环境的污染问题日趋严重,垃圾渗滤液的控制和治理已经成为当前环境保护领域内的一项重大研究课题。膜生物反应器(MBR)是由污水生物处理技术和膜分离技术结合而成的一种新型污水处理与回用工艺,其对于高浓度、难降解有机废水的处理有着一定的研究前景。 本课题以西安市江村沟城市垃圾卫生填埋场产生的垃圾渗滤液为对象,就一体式好氧膜生物反应器在处理垃圾渗滤液过程中的污染物去除效果、污泥特性、溶解性微生物产物(SMP)特性以及膜污染机理展开了研究,试验结果表明:MBR对垃圾渗滤液中污染物的去除效果较好,在HRT为25~112h,COD和NH3-N容积负荷分别为0.32~2.22kgCOD/m3.d和0.14~0.50kgNH3-N/m3.d的条件下,MBR对COD和NH3-N的去除率分别为81.2~88.2%和99%以上;在C/N比为5.2,回流比为300%的条件下,系绩对总氮去除率为75.2~82.2%。 在对反应器中活性污泥特性和SMP特性的试验研究中,稳定状态的污泥浓度随容负荷的增加而升高,本试验中反应器污泥浓度最高达10.4g/L;大量SMP和胞外多聚物(ECP)等难降解物质随着试验运行时间的增加在反应器中积累,使污泥沉降性能变差、污泥活性降低、污泥颗粒粒径减小、生物相变差,同时对反应器中污泥混合液的过滤性能也有负面影响。 在对膜通量衰减规律和膜污染机理的试验研究中,HRT对实际运行中的膜通量衰减速率影响较大,当HRT为25~40h时的膜通量衰减速率最大;将MBR中污泥混合液分为离心上清液、细胞液和溶解性组份,通过死端过滤试验确定出离心上清液中的细小胶体是造成膜污染阻力的主要原因;通过阻力分布试验,得出膜污染阻力主要由凝胶极化阻力和外部污染阻力构成,二者之和占总污染阻力的95%以上;同时MBR中积累的大量细小胶体以及溶解性物质是导致膜污染总阻力增加,混合液过滤性能变差的原因。

【Abstract】 Landfill leachate, produced in the process of landfill disposal, is one kind of organic wastewater of high concentration and difficult treatment, which is very difficult to treat because of its variable quantity and quality and much toxic and harmful ingredient in it. Because it may hazard environment badly, it has been one of the critical problem of pollution control to treat landfill leachate in the nowadays and a long time later. The membrane bioreactor (MBR), a combined process of biological treatment with advanced membrane separation, is a new technology for wastewater treatment and reuse. MBR has the specified research foreground being used for treating the organic wastewater of high concentration and slow-biodegradable nature. Its removal effect of contamination, characteristics of sludge and soluble microbial products (SMP) and mechanism of membrane fouling were investigated to treat the leachate from JiangCungou municipal solid waste landfill site in Xi’an in this dissertation. Experimental results show:MBR has good effect in contamination removal, When volume loading rates of chemical oxygen demand (COD) and NH3-N were between 0.32~2.22kgCOD/m3.d and 0.14~0.50kgNH3-N/m3.d respectively, the MBR had removal efficiencies of COD and NH3-N ranging between 81.2-88.2% and over 99% respectively at hydraulic retention time (HRT) between 25~112h; When C/N and circumfluence rate of mixed liquor were 5.2 and 300% respectively, the system had removal rates of total nitrogen ranging between 75.2~82.2%.In experimental research of the characteristics of sludge and SMP, sludge concentration in stable stage increased with the enlargement of volumetric loading and was above 10.4g/L in process of the experiment; The slow-biodegradable substance such as SMP and extracellular polymers (ECP) were accumulated in the MBR with the extension of running time, which caused sludge settleability to become worse sludge activity to decrease the size of sludge particle to reduce and microbial variation to be bad, as well as contributing to the poor membrane permeability of the mixed liquor.In experimental research of the decline regularity of membrane flux and mechanism of membranefouling, HRT had the greater effect to the decline rate of membrane flux in actual running process, the decline rate of membrane flux was the largest when HRT act as 25~40h; The mixed liquor in the MBR was divided into centrifugal supematant cell liquid and soluble part, the tiny colloid in centrifugal supernatant was ascertained the main reason that created membrane fouling resistance by the filtration tests with a mini-membrane module; The conclusion was obtained that the membrane fouling resistance was mainly completed of polarization layer resistance and external fouling resistance with the distribution tests of resistance, and the sums of two took over 95% of total fouling resistance-, With the extension of experiment running time, a great deal of tiny colloid and soluble substances were accumulated among the MBR, that thereby leaded the total fouling resistance to increacing and the membrane permeability of the mixed liquor to becoming bad.

  • 【分类号】X799.3
  • 【被引频次】14
  • 【下载频次】376
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