【作者】 曾辉平；

【导师】 张杰；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2010， 博士

【摘要】 生物固锰除锰理论为地下水除锰技术开辟了新径,以“弱跌水曝气+一级生物过滤”为典型工艺流程的地下水铁锰生物同层净化技术得到了广泛应用,半个世纪以来地下水除锰难的困扰有了经济高效的解决办法。然而由于我国地域广阔,东西南北水文地质构造以及环境条件相差悬殊,造成各地地下水水质千差万别,铁锰生物同层净化技术在推广应用过程中自然会出现各种新问题,需要更深入研究,从而逐步完善生物固锰除锰理论。地下水厂实际生产运行经验表明,在高浓度亚铁离子存在的情况下,铁锰同层净化生物滤层的培养周期被大大延缓,从正常的1~2个月延缓至6~8个月,且成熟生物滤层的运行稳定性欠佳;另外在地下水中有氨氮存在的情况下,生物除锰滤层的培养受到抑制,只有在氨氮完全硝化之后,才能出现锰离子的完全去除。为此本文针对高浓度亚铁离子以及氨氮对生物除锰的影响进行高铁高锰含氨氮地下水的生物同层净化研究,旨在寻求高铁和氨氮双重影响下的铁锰氨氮生物同层净化滤层的快速启动,并建立高铁高锰含氨氮地下水生物同层净化示范工程。生物除铁除锰滤层中铁锰氧化还原关系的研究结果表明:在生物滤池中存在着复杂的铁锰氧化还原过程,并且与原水水质密切相关,当原水中Fe2+浓度超过3mg/L,高浓度的亚铁离子足以成为高价态的锰生物氧化物还原的电子供体,溶出Mn2+离子,从而破坏除锰生物膜结构及生物除锰滤层。因此只有当Fe2+在滤层上部氧化历程完成之后,在滤层中下部才能构筑高速率的生物化学除锰滤层,Fe2+、Mn2+离子可以在同一滤层中去除,但并非同时去除。在高铁高锰地下水生物同层净化滤池中,滤池上层为除铁段并有微弱的除锰能力,中下层才是高效除锰段,滤层厚度要求较厚。针对高铁型地下水生物除锰滤层成熟期长的问题,根据高浓度亚铁离子对生物除锰滤层的破坏作用这一发现,提出了高铁水质情况下除锰生物滤膜培养受损模型:在使用单层滤料进行生物除锰滤层的培养过程中,反冲洗后滤料的混层会致使部分除锰生物膜与源水中高浓度亚铁离子直接接触从而遭受破坏,延缓除锰生物膜的积累,延缓培养周期。为此又提出了采用双层滤料进行生物除锰滤层快速启动的设想,滤柱实验表明,在双层滤料的使用下,源水水质Fe2+为15mg/L,Mn2+为1.5mg/L时,铁锰生物同层净化滤层成熟周期成功缩短至2个月。含氨氮地下水在生物净化过程中溶解氧需求较大,在本实验水质条件下(Fe2+约为15mg/L,Mn2+约为1.5mg/L,NH4+-N约为1mg/L),要达到铁锰氨氮的同层净化,进水溶解氧需要控制在7.5mg/L以上。溶解氧主要消耗在滤层上部亚铁、氨氮以及其它还原性物质的氧化上,中下部生物除锰滤层能否得到足够的剩余溶解氧是生物滤层除锰成败的关键因素。根据地下水中氨氮的含量,在生物净化过程中需要对曝气工艺乃至整个工艺流程进行充分考虑,实验水质条件下,弱跌水曝气(DO约4~5mg/L)不能满足水质净化供氧需求,需要采用喷淋以及机械曝气等强曝气方式(DO约8.5~11mg/L);当氨氮含量再增大时,受水中氧气饱和溶解度限制,原水一次充氧将无法满足净化需求,从而重新尝试了两次曝气充氧的两级串联过滤方式和持续曝气充氧的曝气生物过滤方式。氨氮对于生物除锰滤层培养过程中的影响来源于氨氮硝化过程中亚硝氮的积累,只有当亚硝酸盐的积累完全消失以后,才会迎来锰的完全去除。含氮地下水生物除锰滤层的快速启动关键在于硝化菌的快速积累,尝试了循环培养生物滤柱启动试验,结果表明循环培养方式加速了硝化菌、以及除锰菌的积累,成功将高铁高锰含氨氮地下水的同层生物净化滤层启动周期缩短至20d。最后通过对松北水厂曝气系统改造、滤池滤层结构的调整以及生物滤层的培养,成功将水厂原有的两级过滤流程改造为一级过滤流程,滤池出水铁锰氨氮浓度控制在0.2mg/L,0.05mg/L及0.2mg/L以下。并对滤池微生物群落结构以及演替规律进行了研究,结果表明滤层不同深度微生物群落结构变化不明显,Zoogloea是滤池的常驻菌群,适应能力较强,对系统的稳定起一定作用。从滤池中分离到一株低温高效除锰功能菌Chryseobacterium sp·MSB-4,与鞘细菌(Sphingobacterium)具有较近的亲缘关系。更多还原

【Abstract】 The purification of groundwater containing manganese has been solved well by biological technology of manganese removal. The typical process flow has been widely used to remove iron and manganese by single filter. But it should be improved by further study to adapt diverse groundwater quality and to be used throughout the country. It is reported that the required start-up period of biofilter for the removal of Mn is typically 1-2 months, but when water contains ammonia, biological Mn removal can take place only after complete nitrification, and when water contains high concentration of Fe2+, the start-up period may be 6-8 months. So in this work we study in the effect of high concentration of Fe2+ and ammonia on the biological removal of manganese in order to shorten the start-up period of biofilter and build demonstration plant for the removal of Fe2+, Mn2+ and ammonia in a single biofilter.According to the research of redox relationship between Fe and Mn in the biofilter, the reduction of biological manganese oxide takes place under high concentration of Fe2+ (>3mg/L), inducing the release of Mn2+ and the destruction of Mn-removal biofilm. Fe2+ and Mn2+ can be removed in a single biofilter, but the efficient manganese removal can only take place in the middle-lower part of the filter after the complete oxidation of Fe2+, so a thick layer is needed for the biofilter. Considering the destruction of Mn-removal biofilm by high concentration of Fe2+, we suppose that: in the culture process of single-media biofilter for Mn-removal, partly formed Mn-removal biofilm would be destroyed by contacting high concentration of Fe2+ in the raw water because of mixed-layer structure of biofilter after backwashing, which would delay the accumulation of biofilm and prolong the start-up period. And dual-media filter is put forward to solve this problem, the result of the filter-column experiment proves that: the start-up period of the dual-media biofilter for the removal of Fe2+ and Mn2+ is shortened to 2 months when the concentration of Fe2+ and Mn2+ is respectively 15mg/L and 1.5mg/L in the raw groundwater.The DO in the influent should be raised above 7.5mg/L for the simultaneous removal of Fe2+, Mn2+ and NH4+-N from groundwater( Fe2+ about 15mg/L, Mn2+ about 1.5mg/L, NH4+-N about 1mg/L). The dissolved oxygen is mostly consumed at the upper part of the filter for oxidization of Fe2+, NH4+-N and other reducing agents. The residual dissolved oxygen concentration in the middle and lower part of the biofilter determines the result of the biological removal of manganese. The aeration system, even the process flow for the biological purification of groundwater should be taken fully into account according to the concentration of NH4+-N in raw water. When the weak cascaded aeration couldn’t afford enough dissolved oxygen for the purification, strong aeration technology should be adopted, for example, spray aeration and mechanical aeration. With the further increasing of NH4+-N, one-stage aeration couldn’t supply adequate dissolved oxygen due to the limitation of saturation of dissolved oxygen, and we try the two-stage filtration process which has two-stage aeration and the aerated biofilter process.The accumulation of NO2--N inhibits the culture process of Mn-removal biofilter and until it disappears, the complete removal of Mn could come true. The accumulation of nitrifying bacteria is the key part for the rapid start-up of biofilter for Mn-removal from groundwater containing NH4+-N. So we try cycling culture for rapid start-up of the biofilter, the result turns out that: the period is shortened to 20 days.In the end, the two-stage filtration process is transformed to one-stage filtration after transformation of aeration system, adjustment of filter structure and culture of biofilm in Songbei water plant, and the concentration of iron, manganese and NH4+-N in the filtrate is lower than 0.2mg/L, 0.05mg/L and 0.2mg/L. Structure and dynamics analysis of microbial community from biofilters indicate that the variation of the structure is inapparent, and Zooglowa has a role to the stability of the biofilter for its wide distribution and great adaptability. A strain Chryseobacterium sp.MSB-4 is isolated, which is efficient for the Mn-removal under low temperature and has close relationship with sheathed bacteria (Sphingobacterium).更多还原