【作者】 张小玲；

【导师】 王志盈；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2004， 博士

【摘要】 氮、磷是造成水体富营养化的主要原因，而传统脱氮除磷工艺普遍存在工艺流程较长，占地面积大、基建投资高等缺点。人们积极展开新型除磷脱氮理论及工艺的研究，其中短程硝化—反硝化脱氮、反硝化聚磷以及同步硝化反硝化工艺具有节约能源、减少污泥量和占地面积等优点，受到广泛地关注。本文对附着生长式(生物紊动床)和悬浮生长式(SBR)生物反应系统内的短程硝化—反硝化、悬浮生长式反应系统(SBR)内反硝化聚磷及同步硝化反硝化进行基础研究。主要研究成果如下。 (1)在填充轻质载体的生物紊动床内，温度为25℃左右，pH为7.2～8.0，进水氨氮浓度为300mg／L的条件下，将DO降低到0.5～1.0mg／L，经过30d后，系统内形成了稳定的短程硝化，亚硝酸积累率稳定在80％以上，氨氮去除率在90％以上。此时，亚硝酸菌的数量比高溶解氧时增加约4倍，而硝酸菌的数量减少约40％，亚硝酸菌在生物膜上成为优势菌群；导致氨氮和亚硝酸氮氧化速率严重不匹配，氨和亚硝酸氧化速率分别为1.5kgN／m~3·d和0.02kgN／m~3·d。证实了低溶解氧下附着生长生物反应系统中短程硝化是通过生物膜上两类硝化菌的竞争选择后促使两类菌的数量比例和活性发生了改变所致。 (2)在生物紊动床内有机物对低溶解氧下短程硝化过程的影响研究结果表明：DO=0.5～1.0mg／L、TOC＞100mg／L(TOC／N=1∶3)的条件下，短程硝化过程受到破坏。低溶解氧下异养菌和硝化菌之间也存在着动力学选择过程，硝化菌由于竞争不到氧，活性受到影响，数量大大减少。 (3)在SBR内，温度为25℃左右，pH为7.5～8.5，进水氨氮浓度为300mg／L的条件下，控制溶解浓度为0.3～0.5mg／L也能实现短程硝化。SBR周期内低、高溶解氧交替环境是实现短程硝化的控制条件，合理的高溶解氧时间段是维持亚硝酸积累稳定性的保证，亚硝酸的饱食—饥饿特性是该条件下短程硝化实现的生物学基础。游离氨对亚硝酸的积累起到一定促进作用，实现短程硝化的温度和泥龄范围较大，在温度为21～30℃、泥龄为15～40d的范围内都可以实现稳定的短程硝化。西安建筑科技大学博士论文 (4)在SBR内研究了溶解氧和有机碳源的投加方式对同步硝化反硝化效果的影响。低溶解氧下的同步硝化反硝化发生的机理应归结于微环境理论。有机碳源的投加方式对同步硝化反硝化效果影响显著。当采用半连续碳源投加方式时，在进水氨氮浓度为300mg几、投加COD总浓度为600m叭的条件下TN去除率达到80%以上。 (5)在进水COD浓度为350mg几，温度为25oC，pH为7.0一7.5的条件下，在SBR内进行基质及环境条件对反硝化聚磷的影响特性试验。试验结果表明，反硝化聚磷速率随着硝酸盐浓度的增加而增加，而当硝酸盐浓度大于20m叭时，反硝化聚磷速率与20mg几的反硝化聚磷速率差别不大，而反硝化聚磷效果会因为硝酸盐残留而受到影响;在相同的硝酸盐浓度下，反硝化聚磷效果随着缺氧时间的延长而增加;缺氧段后维持一定的好氧时段有利于反应器污泥的沉淀和反硝化聚磷效果的稳定。 (6)以亚硝酸为电子受体的反硝化聚磷的诱导试验表明，污泥经过驯化诱导是可以以亚硝酸为电子受体聚磷的，亚硝酸的投加方式对反硝化聚磷菌的诱导时间和最终的聚磷效果影响很大。采用连续投加亚硝酸方式时，经过23天的驯化培养，缺氧段最大聚磷速率达到10.44mgp/955·h。 (7)在sBR内温度为25℃，pH为7一7.5的条件下研究了反硝化聚磷颗粒污泥的培养过程、理化特性及颗粒污泥降解污染物的能力。研究结果表明，颗粒污泥的形成是COD负荷、水流剪力、HRT以及沉淀时间共同作用的结果。颗粒粒径范围为50一900 pm，颗粒污泥含水率在%.78%一98.14%之间，颗粒污泥比重为1.002一1.006。污泥沉降性能极好，Svi在25mL/g一40mL/g之间。由于颗粒污泥的形成sBR的coD去除负荷及脱氮除磷能力大大提高。有机物去除负荷1.4%kgcoD/m，·d，硝酸盐及磷酸盐的去除分别为0.21kgN/m3·d和0 .o6kgP/m，·d。更多还原

【Abstract】 Biological nutrient removal processes were introduced into wastewater treatment because nitrogen and phosphorus induced eutrophication of closed water bodies. However conventional biological nutrient removal processes exist some problems such as system complex, large footprint, high investment, and etc. Short-cut nitrification-denitrification, simultaneous nitrification-denitrification and denitrifying phosphorus removal are novel biological nutrient removal technologies. The processes have many advantages, such as high efficiency, energy saving and less sludge etc. So these new technologies are being paid more and more attention by environmental engineering experts.In this paper, short-cut nitrification-denitrification was studied in the attached growth system (Biological Turbulent Bed Reactor, BTBR) and suspended growth system (Sequencing Batch Reactor, SBR), respectively. In addition, simultaneous nitrification-denitrification and denitrifying phosphorus removal were studied in SBR reactor. From the experiments I get the main conclusions as follows.(1) In a BTBR, DO concentration was controlled between 0.5 and 1.0mg/L and 300mg/L of ammonium nitrogen was filled, the 80% of nitrite could be reached stably; 90% of ammonium was removed at 25℃, the value of pH 7.2-8.0. The MPN test showed that ammonium oxidizers had dominated in the biofilm at the end of dynamic selection under low DO concentration.(2) The effect of organic carbon concentration on short-cut nitrification was also studied in BTBR. The results showed that nitrification system was destroyed with DO=0.5~1 .0mg/L TOC >100mg/L and TOC/N=1:3, because nitrifiers couldn’t compete for DO with heterotrophic bacteria.(3) The alternation of low DO concentration and high DO concentration was the key factor for a successful short-cut nitrification in an SBR. Ammonium oxidizers had feast-famine abilities,so it could endure the fluctuation of DO and survived in the reactor, but nitrite oxidizers did not.(4) Effects of DO concentration and feed mode of organic carbon on simultaneous nitrification-denitrification were studied. The aerobic zone and anoxic zone coexisted in a floe, so nitrification and denitrification took place simultaneously at low DO. Feed mode of organic carbon influenced the efficiency of nitrogen removal. 80% of nitrogen removal efficiency could be reached at 300 mg/L of ammonium nitrogen and 600mg/L of COD using batch feed mode .(5) Nitrate concentration was one of the factors affecting the denitrifying phosphorus removal. Generally, a higher Nitrate concentration benefits denitrifying phosphorus removal. But when the Nitrate-nitrogen concentration was enhanced over 20mg/L, the phosphorus removal efficiency couldn’t be improved. At the same Nitrate concentration, denitrifying phosphorus removal efficiency could be promoted with the increase of anoxic time. In order to keep steady phosphorous removal efficiency and sludge settle ability, an aerobic stage should be added following anoxic stage.(6) Nitrite can be used as electron acceptor in denitrifying phosphorus removal. Feed mode of nitrite had significant influence on denitrifying phosphorus removal. Anoxic phosphorus assimilation rate could be reached 10.44mgP/gSS-h after 23 days with continues feed mode.(7) Sludge granular with denitrifying phosphorus removal activity was cultivated In an SBR. The effects of different operational conditions on formation of granular were studied such as COD loading, settling time, HRT and shear force. The dimension of granular was between 50 m and 900 m,. Its water content was at 96.78% -98.14%, specific gravity 1.022-1.006, SVI of sludge 25~40mL/g, COD removal loading could be reached to 1.496kgCOD/m3-d, nitrogen and phosphorus removal loading could be reached to 0.21 kgN/m3-d and 0.06kgP /m3-d respectively.更多还原