【作者】 刘晓；

【导师】 吕炳南； 董春娟；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2010， 博士

【摘要】 膨胀颗粒污泥床（Expanded Granular Sludge Bed）,简称EGSB反应器,与普通厌氧反应器相比,具有传质效果好、处理效率高、耐冲击性强等优点。EGSB反应器对进水水质和运行环境的适应性较好,它不仅适于处理高浓度有机废水,对于低浓度废水、低温（15²0℃）和低溶解氧状态也表现出较好的适应性。微氧（microaerobic）指介于厌氧和好氧之间的兼性状态,微氧生物处理在较低的供氧条件下就能实现有机物和营养盐的同步去除,具有能源利用率高、剩余污泥少等优点。本文主要研究了EGSB反应器在微氧状态下的运行情况,其中包括颗粒污泥的培养、COD和氮磷去除效能、以及相关的影响因素。首先采用EGSB反应器厌氧培养颗粒污泥。用模拟污水（COD为400¹650mg/L）并在接种消化活性污泥中混以少量破碎颗粒污泥,在25℃条件下,以适宜的上升流速和逐步增加的容积负荷,快速完成污泥颗粒化。颗粒污泥形成以后,转为实际生活污水继续培养。在13²6℃、进水COD为144⁶18mg/L、水力停留时间（HRT）为0.6¹.6h、容积负荷为2.5¹9.6kg/（m³·d）的情况下运行3个多月,稳定运行期间COD平均去除率可达80%左右,出水COD低于100mg/L。培养成熟的厌氧颗粒污泥粒径大都在0.43²mm;沉速为14⁹5m/h;比产甲烷活性为0.34⁰.45LCH₄/（gVSS·d）;颗粒污泥结构致密,内部杆菌和球菌聚集生长。在颗粒污泥培养过程中发现,温度、剪切强度、HRT和容积负荷都对运行效果和颗粒污泥性能产生影响。温度低于15℃或者平均剪切强度超过32.1×10^-3Pa都会加速颗粒污泥解体,降低处理效果;但当温度高于15℃时,缩短HRT和提高容积负荷反而能使颗粒污泥活性增强,处理效率有所提高。随后进行了微氧状态下的运行研究。试验用水仍为生活污水,运行温度为18²7℃。采用逐步增加溶解氧的方式对厌氧颗粒污泥进行微氧驯化。驯化成功后,污泥性能稳定,净化效果显著提高。在DO为0.3⁰.5mg/L、HRT为8h、回流比为8:1¹0:1、容积负荷为0.4¹.9kg/（m³·d）的情况下,COD、氨氮、总氮、总磷和SS的平均去除率分别为94%、83%、81%、36%和89%。研究发现,溶解氧、HRT、回流比、污泥浓度和污泥负荷都对微氧状态下的除污染效果产生影响。经试验确定的最佳运行参数为:DO为0.3⁰.4mg/L、HRT为8h、回流比为8:1、MLSS为11¹6g/L、污泥负荷低于0.15kgCOD/（kgMLSS·d）。此时,COD、氨氮和总氮的平均去除率分别为93%、84%和82%。微氧条件下反应器能实现高效稳定的同时硝化反硝化脱氮,微氧环境和高污泥浓度都对污染物去除起到强化作用。与活性污泥法脱氮相比,工艺水力停留时间较短、容积负荷较高、净化效果好;可减少34%的耗氧量和四分之三的剩余污泥。在微氧条件下,溶解氧和污泥负荷对颗粒污泥性能影响较大。当DO低于0.4mg/L、平均污泥负荷低于0.12kgCOD/（kgMLSS·d）时,颗粒污泥结构致密,沉降迅速,产甲烷和脱氮活性良好。污泥中微生物种类丰富,丝状菌生长较少。提高溶解氧或增加污泥负荷都会造成污泥沉降性能下降、污泥解体和产甲烷活性降低。当平均污泥负荷增加到0.18kgCOD/（kgMLSS·d）时,颗粒污泥丝状化程度和解体数量明显增加。微氧状态下颗粒污泥内部以及污泥床不同高度分布着不同的优势种群,多种降解途径使除污染效果得到改善。动力学分析表明,同时硝化反硝化脱氮的最佳溶解氧为0.41mg/L。在同时硝化反硝化的基础上,建立了微氧颗粒污泥内氧的传质动力学模型,应用模型对颗粒污泥内氧的分布进行了模拟,并评价了内扩散作用对耗氧反应的影响。结果显示,DO越低、颗粒越大,越不易被氧渗透;内扩散对耗氧反应的影响越明显。用不同DO条件下的实测污泥耗氧速率对模型进行了验证,得到较好吻合。本研究通过各种运行参数的有效调节,用EGSB反应器厌氧颗粒污泥成功培养出净化效能良好的微氧颗粒污泥,为生产实践的运行调控提供依据。更多还原

【Abstract】 Expanded Granular Sludge Bed （EGSB） reactor exhibits many advantanges such as better mass transffer, higher treatment efficiency and more resistance in shock load compared with conventional anaerobic reactors. EGSB reactor has a good adaptability for the changes of influent quality and operating condition, namely stable treatment can be obtained for both high and low strength wastewater even at low temperature（15-20℃） or low oxygen. Microaerobic condition is the transitional state betweent anaerobic and aerobic conditions. Microaerbic bio-treatment can remove organics and nutrients simultaneously with a high energy efficiency and low yield of excess sludge. This paper focuses on the performance of EGSB reactor in microaerobic condition, Study included the cultivation of granular sludge, removal efficiency of COD and nutrients as well as the related factors that influence the operation effect.First, granular sludge was anaerobicly cultured in EGSB reactor. The feed water was simulative wastewater（with COD of 400¹650mg/L） and the inoculum was digested sludge mixed with a little disintegrated granular sludge. Sludge granulation was rapidly achieved with suitable upflow rate and step-up volumetric loading rate（VLR） at 25℃. As granules formed, the feed water was changed to domestic wastewater. During the three more months operation, temperature was 13-26℃and influent COD was 144-618mg/L, the hydraulic retention time （HRT） and VLR of COD were set at 0.6-1.6h and 2.5-19.6 kg/（m³·d） respectively, and the average COD removal rate reached 80% with effluent COD below 100mg/L during stable stage. Most of the anaerobic granules were 0.43-2mm in diameter, with sedimentation velocity of 14-95m/h, and the specific methanogenic activity ranged in 0.34-0.45LCH₄/（gVSS·d）. The anaerobic granules were compact with bacillus and coccus colonies inhabited at different zones. It was observed that temperature, hydrodynamic shear conditions, HRT and VLR had influence on running efficiency and sludge property. Either temperature down below 15℃or the average shear rate increased above 32.1×10^-3Pa accelerated degranulation thus deteriorated the effluent quality. Nevertheless, at above 15℃, better granular activity and higher treatment efficiency were obtained by shortening HRT and increasing VLR.Then miceoaerobic operation was carried out based on EGSB reactor. The experimental water was still domestic wastewater and the operating temperature was 18-27℃. By increasing the dissolved oxygen gradually in the reactor, microerobic granules developed from anaerobic ones. After startup, the microaerobic granules had stable characteristics and much enhanced decontaminating capability. When DO, HRT, reflux ratio and VLR of COD were set at 0.3-0.5mg/L, 8h, 8:1¹0:1 and 0.4-1.9kg/（m3·d）, respectively, the average removal rate for COD, ammonium, total nitrogen, phosphorus and SS were 94%, 83%, 81%, 36% and 89%, respectively.Study showed that pollutants removal was related to factors such as DO, HRT, reflux ratio, sludge concentration and sludge loading. The optimum parameters were proved to be: DO 0.3-0.4mg/L, HRT 8h, reflux ratio 8:1, MLSS 11-16g/L and COD sludge loading rate 0.15kgCOD/（kgMLSS·d）. Under these conditions, the average removal rates of COD, NH4+-N and TN were 93%, 84% and 82%, respectively.Nitrogen was effectively removed through simultaneous nitrification and denitrification in microaerobic condition. Both the microaerobic environment and high sludge concentration benefited pollutants removal. As compared with the activated sludge techniques for nitrogen removal, this process had the features of shorter HRT, higher volumetric loading, and better decontaminating effect, cutting down 34% aeration and three-quarter excess sludge yield.Both DO and sludge loading influenced the granular property in microaerobic condition. When DO level was below 0.4mg/L and sludge loading rate was less than 0.12kgCOD/（kgMLSS·d）, the granules were compact with good settling property and were activitive in methanogenesis and nitrogen removal. There were less filamentous bacteria in granules since the microbial groups distributed were relative abundant. However, increasing in either DO level or sludge loading resulted in worse settlement, accelerated degranulation and diminished methanogenesis. It was observed that more filamentous and disintegrated granules appeared when the average sludge loading of COD rose to 0.18kgCOD/（kgMLSS·d）.It was the diversity in microbial groups and metabolic pathways that improved treatment effect since kinds of populations dominanted in granules and different part of sludge bed. Kinetics analysis showed that the optimal DO was 0.41mg/L for simultaneous nitrification and denitrification to remove nitrogen. On the other hand, model of oxygen transfer was built to simulate oxygen distribution in granule based on simultaneous nitrification and denitrification. Moreover, the influence of internal diffusion on aerobic reaction within granule was evaluated. According to the calculating results, either lower DO or larger granule would prevent oxygen from penetrating thus aerobic reaction was much effected by internal diffusion. Simulating results were then applied to evaluate the oxygen consumption in different conidtion with well agreement between experiment and prediction.The present study cultured excellent microaerobic granules from anaerobic ones in EGSB reactor by controllong operating parameters, which provided reference for the practical operation and regulation.更多还原