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固定化包埋硝化菌去除废水中氨氮的研究
Study on the Removal of Ammonia by Immobilized Nitrobacteria Pellets
【作者】 邓岩岩;
【导师】 张振家;
【作者基本信息】 上海交通大学 , 环境工程, 2010, 硕士
【摘要】 本文研究了固定化包埋硝化菌和生物膜在驯化阶段去除氨氮的各种特性,及驯化结束后不同影响因素对其活性及硝化特性的影响。固定化包埋硝化菌在流化床内培养,生物膜反应器内的硝化菌以生物膜的形式附着在软性填料上生长。最后研究了固定化包埋硝化菌处理玉米发酵废水时的硝化能力。实验主要针对硝化细菌的驯化、温度和溶解氧对两个反应器硝化反应的影响、不同储存条件对固定化包埋硝化菌活性恢复的影响及固定化包埋硝化菌处理玉米发酵废水的能力几个方面展开。主要实验结论如下:1)保持系统连续进水的条件下,固定化包埋硝化菌经过37天的驯化,颗粒活性由初期的10 mgNH4-N/L·h上升至23.4mgNH4-N/L·h。生物膜反应器内的硝化菌硝化速率由初期的由开始时的2.0mgNH4-N/L·h升高至结束时的11. 8mgNH4-N/L·h。2)同期颗粒活性数据与PCR扩增实验结果表明,对包埋硝化菌进行驯化期间,包埋颗粒内部硝化菌含量明显增加,颗粒内部生物量大幅提高。3)溶解氧从4mg/L向2mg/L转变的过程中,固定化包埋硝化菌与生物膜反应器内的的硝化菌硝化能力均受到影响,但流化床的硝化能力要远高于固定床。未降低溶解氧前流化床的氨氮降解负荷最高达34.1mgNH4-N/L·h,而固定床最高仅为11.8mgNH4-N/L·h。降低溶解氧后流化床氨氮降解负荷为28.4mgNH4-N/L·h,固定床为9.5mgNH4-N/L·h。此外,在低溶解氧条件下两反应器均出现一定程度的亚硝酸氮积累情况。4)温度从高向低的转变过程中,两反应器内硝化菌硝化速率均有所降低,亚硝酸氮积累现象减轻。温度高时易出现亚硝酸氮积累。5)固定化包埋硝化菌在较高活性时放置在4℃下保存后可迅速恢复活性,7天内颗粒活性从储存后取出时的1. 8mgNH4-N/L·h上升至13.8mgNH4-N/L·h。6)使用固定化包埋颗粒处理玉米发酵废水中的氨氮,有较好的去除效果,系统连续运行效果稳定。废水中不存在抑制硝化菌活性的物质。当体系进水中氨氮浓度在40mg/L左右,停留时间为2.5h~3.5h之间,溶解氧在4mg/L时,出水氨氮浓度基本上可以达到15mg/L以下,满足排放标准。废水中存在的有机物对硝化反应影响不大。
【Abstract】 Ammonia removal features of nitrobacteria in immobilized pellets and bio-film during the acclimation phase were studied and the effects of surrounding factors on their activity were discussed after the acclimation. Immobilized nitrobacteria were cultivated in the fluidized bed while nitrobacteria in the bio-film grew on the elastic plastic media in the fixed bed. The nitro-bacterial degradability of immobilized nitrobacteria in the treatment of the corn distillery wastewater was also investigated.The experiments mainly focused on the acclimation of nitro-bacteria, the effects of temperature and DO on the nitro-bacterial degradability of the two reactors, the influence of storage conditions on the nitro-bacteria activity recovery, and the nitro-bacterial degradability of immobilized nitrobacteria in the treatment of corn distillery wastewater.The major conclusions were drawn as follows:1) In the continuous experiment, the ammonia oxidizing ability of the pellets increased from 10mgNH4-N/L·h to 23.4 mgNH4-N/L·h after 37 days’acclimation while the nitrification ratio of the fixed bed increased from 2.0 mg mgNH4-N/L·h to 11. 8mg mgNH4-N/L·h.2) The result of PCR experiment showed that the quantity of the ammonia oxidation bacteria increased substantially during the acclimation.3) When DO declined from 4mg/L to 2mg/L, the nitrification ability of two reactors decreased while the nitrification ability of the fluidized bed is far better than that of the fixed bed. DO of 4mg/L enabled both, reactors to reach the maximum nitrification rate of 34.1mgNH4-N/L·h and 11.8mgNH4-N/L·h respectively, while at 2mg/L, the two reactors had lower nitrification rate of 28.4mgNH4-N/L·h and 9.5mgNH4-N/L·h, respectively. Besides, NO2-N accumulation was detected in both reactors.4) When the temperature was decreased, both reactors were affected and the NO2-N accumulated less. Higher temperature tended to cause nitrite accumulation more likely.5) After long-term storage, the immobilized nitrobacteria kept at 4℃showed quick recovery from an inertia status. Its nitro-degrading rate increased from 1. 8mgNH4-N/L·h to 13.8mgNH4-N/L·h after 7 days’acclimation.High nitrogen removal rate and steady operation were obtained when using the immobilized bacteria to treat the corn distillery wastewater. No inhibitive material was found in the wastewater and the organic material in the water had a limited influence on the nitrification rate. At the influent ammonia of 40mg/L, HRT of 2.5h-3.5h, and DO of 4mg/L, the NH4-N concentration in the effluent water was lower than 15mg/L and was able to meet the requirement.
【Key words】 immobilized nitrobacteria; biofilm; nitrification rate; NO2-N accumulating ratio; corn distillery wastewater;