【作者】 冯晶；

【导师】 王毅力；

【作者基本信息】 北京林业大学 ， 生态学， 2014， 博士

【摘要】 本论文针对乡村生活污水的生态环境污染问题,通过厌氧折流板反应器(ABR)与改进填料的人工湿地组合技术对乡村生活污水的动态处理试验,结合Fe3+、Fe2+对ABR启动过程的强化效果与污泥颗粒化特征的结果,探讨了ABR-人工潜流湿地技术处理乡村生活污水的可行性及其关键控制因子的强化效果与机制,为乡村生态环境的改善提供技术支撑。获得的主要研究结果如下：ABR-人工湿地处理实际生活污水的动态试验结果表明：在进水CODCr=200-1200mg/L, TN=100-150mg/L, NH3-N=50-150mg/L的条件下,ABR的启动时间为130d,启动完成后继续运行49d,出水CODcr达到城镇污水处理厂二级排放标准(GB18918-2002),相应的TN、TP的平均去除率分别为10.28%、12.49%。栽植芦苇的人工湿地模拟装置采用了给水厂污泥作为强化除磷的填料,其中所含的铝铁物质可以吸附污水中的磷,理论吸附量最高值为13.07mg(PO43--P)/g,优于沸石、钢渣与粉煤灰等常规湿地填料材料。ABR出水经过人工湿地模拟装置的进一步处理后,出水CODcr稳定在20mg/L左右,相应的去除率约为80%,总磷在2.05-6.51mg/L范围,平均去除率为39.2%,氮去除率仅为10%-20%,主要受湿地微生物和植物生长状况的影响。ABR在上述常规启动运行过程中,各格室污泥中的微生物发生了部分相分离现象。污泥在颗粒化过程中,其长宽比经历了增长-急剧下降-趋于稳定三个阶段,启动成功后颗粒污泥具有趋于球形的密实结构,表面较为光滑。成熟厌氧颗粒污泥的平均粒径为0.54-0.92mm,沉降速度为1.8-29.1mm/s,有效密度为2.82-71.32kg/m3,质量分形维数为2.17-2.69,具有内层密实外层疏松的特征,基于Logan公式确定的颗粒污泥孔隙率为0.60-0.95,而通过石蜡切片图像确定的平均孔隙率仅为0.66-0.81。还提出了ABR处理低浓度生活污水时颗粒污泥成长过程与成熟颗粒污泥的概念模型。ABR的强化启动过程研究表明：直接投加Fe3+不能提高ABR的处理效果,而采用铁炭微电解装置产生的Fe2+进行强化启动,可以将ABR的启动时间从对照试验的51d缩短为38d,出水CODCr为120mg/L,其去除率提高了10%。ABR各格室中加入Fe2+加速了污泥的生长速度,最终形成了表面光滑结构密实的球形颗粒污泥,各格室中这些颗粒污泥的平均粒径为0.28-0.73mm,而对照ABR和Fe3+作用下的ABR内污泥颗粒的平均粒径仅为0.04-0.20mm。Fe2+强化启动的ABR运行稳定后颗粒污泥的水凝胶结构分析表明：该颗粒污泥水凝胶结构的关键物质可能为：蛋白质与α-多糖。在中性pH与高离子强度下颗粒污泥的储能模量(G’)、结合能(Ec)与屈服应力(τ)较高,表明该颗粒污泥水凝胶结构的强度和弹性较好。在温度为25℃-75℃范围内,该颗粒污泥的平衡水含量(EWC)变化不大；pH<4时EWC急剧降低,pH>10时EWC迅速升高；离子强度的升高导致了EWC的降低。在本研究的环境条件变化范围内,颗粒污泥的渗透压为负值,具有通过“EPS半透膜”向环境释水的趋势,这与“道南平衡”理论中的凝胶渗透现象的影响因素相关。此外,通过铁碳微电解装置产生的Fe2+投加到ABR中,进水Fe2+浓度为150mg/L,启动过程中反应器上清液pH值维持在7.0左右,是产甲烷细菌生长的适宜条件。采用PCR-DGGE技术解析了ABR成熟颗粒污泥中真细菌的分子生态学特征,结果表明,与对照ABR相比,Fe2+的加入改变了ABR各格室污泥中微生物种群的分布,前者各格室内分布着大量的螺杆菌属与泥生绿菌属微生物,且在第2格室发现大量的梭菌属与气单胞菌属细菌,第3-5格室发现较多的Uncultured Sulfuricurvumsp.；后者前2个格室的优势种为Uncultured Sulfuricurvum sp.,后3个格室内该细菌数量减少。并且Fe2+的投加导致ABR第二格室至第五格室内微生物多样性指数降低。论文研究结果证明,ABR-人工潜流湿地分散处理乡村生活污水时,通过铁炭微电解单元释放的Fe2+强化ABR的启动过程、给水厂污泥除磷填料和典型湿地植物强化人工湿地对有机物和磷的去除效果等技术措施的实施,不仅可以缩短关键单元的启动时间,而且提高污染物去除效果,可以作为乡村生态环境改善方面生态处理的储备技术。针对北京市昌平区康陵村低浓度生活污水的水质水量特征,确定了Fe2+强化启动的ABR反应装置为中试工艺的预处理单元,含有给水厂污泥强化除磷填料和典型湿地植物的人工潜流湿地装置作为中试工艺的深度处理单元,计算了4m3/d的ABR-人工潜流湿地中试工艺装置以及铁碳微电解装置的尺寸,绘制了单元装置的结构图。比较了ABR-人工湿地工艺系统与其它乡村生活污水处理系统,分析了前者的优势。更多还原

【Abstract】 In this paper, to treat the ecological environmental pollution caused by rural sewage, a combination of anaerobic baffled reactor(ABR) and constructed wetland with the enhanced wetland media was employed for rural sewage disposal, of which dynamic features were explored. The ABR start-up experiment was also conducted by adding Fe3+and Fe2+, respectively. Furthermore, the feasibility of the ABR-constructed wetland and the effect of key controlling factors on the performance of the wetland as well as the corresponding mechanism were investigated. The results of this paper would provide technical support for improving the rural ecological environment. The results were as follows:Under the condition of COD of200-1200mg/L,TN of100-150mg/L, NH3-N of50-150mg/L in the influent, the start-up time lasted130d and the CODcr in the effluent of ABR reached the second discharge standard of pollutants for municipal wastewater treatment plant(GB18918-2002)49-day later, and the corresponding average TN and TP removal was10.28%and12.49%,respectively. The effluent was discharged to the simulated apparatus of constructed wetland for the further purification. In the apparatus, reed was planted and water treatment residual (WTR) was considered to be the enhanced wetland media. Due to the presence of Al and Fe in WTR, its maximum adsorption capacity of phosphorus was13.07mg(PO43--P)/g, which was higher than that of normal constructed wetland substrate, like zeolite, steel slag, coal ash etc. The effluent COCr of the simulated apparatus was stable at about20mg/L, and the corresponding CODCr removal was about80%. The effluent CODcr ranged from2.05mg/L to6.51mg/L, and the average TP removal was about39.2%. The nitrogen removal was only in the range of10%to20%, which was due to the influence of the microbial and growth of wetland plants.During the ABR start-up and running process, the partial microbial separation in ABR sludge was observed. The aspect ratio of the granules in ABR firstly increased followed by a dramatically decreasing, then tended to be stable. The anaerobic granules produced in ABR became more and more regular in surface and compact in structure. The size of the granules increased to0.54-0.92mm after a duration of stable running. The corresponding settling velocity and the effective density of these granules ranged from1.8mm/s to29.1mm/s and from2.82kg/m3-71.32kg/m3,respectively. Based on Logan’s equation, the porosity of these granules was in the range of0.60-0.95, whereas the average porosity of these granules was only0.66-0.81determined from the paraffin section image.Adding Fe3+alone did not improve the performance. By comparison, when ABR was dosed Fe2+by the iron carbon micro electrolysis device, it took ten days shorter to start up the ABR than the control one which lasted45days. Meanwhile, the CODCr was120mg/L in the effluent and the removal efficiency increased by10percent. Dosing Fe2+to ABR accelerated the granulation, improved the capability of resistance to shear deformation, and promoted the growth of granular sludge in the length direction and the width direction. Finally, the sphere-like granule formed, which had smooth surface and dense structure. The average size of the granules in the five compartment was0.28-0.73mm, while it was only in the range from0.04mm to0.20mm for the control ABR and the ABR dosed Fe3+.The protein and a-polysaccharide might be the main contributor to the formation of anaerobic granule hydrogel. Under conditions of neutral pH and high ionic strength, the storage modulus(G’), energy of cohesion(E) and yield stress(τ) of the granules were higher, which indicated that the granules exhibited stronger elasticity and strength. The equilibrium water content (EWC) of the anaerobic granules kept almost stable when the temperature was in the range of25℃and75℃. As pH<4, the sharp decrease of the EWC indicated the decrease of the water content in sludge. While the EWC increased rapidly when pH>10. The high concentration of NaCl in the solution led to the reduction of the EWC. Under these conditions, the osmotic pressure was negative, which showed that the granules tended to release water. This tendency was controlled by Donnan equilibrium.Adding Fe2+to ABR by control the Fe2+concentration of150mg/L, maintained the pH in ABR at about7.0, under which the methane-producing bacteria grew well. Through the PCR-DGGE technology, the distribution of microbial community in the ABR was characterized, and the results was as following. A variation in the microbial community in the ABR compartments was observed with the addition of Fe2+. In the ABR dosing with Fe2+, the dominant species was Uncultured Sulfuricurvum sp in the first and second compartment, and its quantity decreased in the latter three compartments. However, in the control ABR, a great number of Uncultured Sulfuricurvum sp. and Chlorobium limicola was observed in all the five compartments. In addition, Uncultured Clostridiales bacterium and Tolumonas auensis dominated in the second compartment, Uncultured Sulfuricurvum sp and great quantity of Uncultured Sulfuricurvum sp was observed in the fifth compartment. The microbial diversity analysis showed that the microbial diversity decreased in ABR apart from in the first compartment due to the Fe2+dosing.In this paper, ABR-constructed wetland was employed for decentralized treating rural domestic sewage. The ABR start-up was strengthed by Fe2+produced in the iron carbon micro electrolysis device, and the wetland was strengthed by WTR and typical plants, through which the start-up period of key unit was shortened and the removal efficiency of polluant in sewage was increased. The combination of ABR-constructed wetland could be recommended techniques for improving rural ecological environment. Based on the results of the above-mentioned and the analysis about the water quantity and wastewater characterization of the low-strength rural sewage produced in Kang Ling Village in Beijing, the ABR that was celebrated start-up by Fe2+was considered as the pretreatment unit. A constructed subsurface wetland that contained WTR to ennaced phosphorus removal was employed as the advanced treament unit. An4.0m/d pilot-scale improved ABR-constructed’ wetland and iron carbon micro electrolysis device were designed, and the draft was drawn after calculating the structure parameters of every unit. In addition, the improved ABR-constructed wetland with enhanced media was compared with other technology used in rural sewage disposal.更多还原