【作者】 蔡亮；

【导师】 王林权； 杨建州；

【作者基本信息】 西北农林科技大学 ， 农业环境保护与食品安全， 2009， 硕士

【摘要】 北京是世界上严重缺水的大城市之一,水资源紧缺已成为制约其经济社会可持续发展的主要瓶颈。北京郊区是首都的生态屏障,也是北京主要的水源涵养区和供给地。农村污水对水源保护和水环境的影响日益显现。本文结合北京市的现实情况和发展需求,以两种不同膜组件为研究对象,研究和探讨两种不同膜组件应用于重力出水式膜生物反应器的可行性。为解决北京市水资源短缺、减少农村污水排放、有效控制河流,水库和水源地污染等提供技术支撑。经启动试验、模拟试验和中试运行试验等,得到以下主要结论。1、膜组件A(膜丝材质为聚乙烯,直径0.54 mm,孔径0.4μm,膜面积为9.0 m2)的清水比通量为42.611[L·(m2·h)-1/KPa],纯膜阻力为1.47(108m-1);膜组件B(膜丝材质为聚偏氟乙烯,直径0.80 mm,孔径0.22μm,膜面积为12.5 m2)的清水比通量和纯膜阻力分别为40.839[L·(m2·h)-1/KPa]和2.66(108m-1)。膜组件A在重力出水模式下的初始膜通量在11 L·(m2·h)-1左右,膜组件B在重力出水模式下的初始膜通量在7.5 L·(m2·h)-1左右。启动时期两膜组件对于污水中CODcr的去除率保持在80%以上;污水中NH4+-N的去除率保持在60%以上。2、在污泥浓度(MLSS)为2000mg/L～3000 mg/L的情况下,膜组件A的膜通量随着水头重力的增加而增加;在曝气强度为50 m3·(m2·h)-1下,膜组件A在4个给定水头重力下,均达到最大膜通量。在试验期内,曝气强度对膜通量的衰减影响较小,膜通量无明显下降的现象,其经济曝气强度约为50 m3·(m2·h)-1,平均膜通量为8.7 L·(m2·h)-1。膜组件B的膜通量也随着水头重力的增加而增加;曝气强度对于膜组件B膜通量的变化也无明显的影响;当曝气强度在40 m3·(m2·h)-1～60 m3·(m2·h)-1时,对膜通量的衰减影响较小,膜通量无明显下降的现象。其经济曝气强度约为40 m3·(m2·h)-1,在此曝气强度下,膜组件B平均膜通量为3.7 L·(m2·h)-1。膜组件A于长期运行下,具有较好的抵抗膜污染的特性,可以保持较高的膜通量;而膜组件B在长期抵抗膜污染能力上有待加强。同时重力水头对膜组件B的膜通量有较大的影响,单位压力膜通量(J/Δp)的最大递增率可达到168.75%,而膜组件A的单位压力膜通量(J/Δp)的最大递增率仅为16.95%。3、经济曝气强度约为40 m3·(m2·h)-1时,重力出水式膜生物反应器的对氨氮、CODcr、浊度的平均去除率分别为:97.8%、90.8%、99.4%。对比膜通量与曝气强度的关系,膜组件A比膜组件B具有更好的经济性,适和于改造为重力出水式膜生物反应器。4、空曝气只是对膜表面的污染物质有一定的冲刷作用,而对膜孔内部的污染物质的清洗作用有限。不同空曝气时间后,膜组件A的膜通量只恢复到了重力出水模式下的平均初始膜通量的26.9%～39.8%。而膜组件B则可恢复到了重力出水模式下的平均初始膜通量的49.0%～70.0%。说明膜组件A膜孔内污染严重,而膜膜组件B以膜外污染为主。空曝气对膜组件B的清洗效率优于膜组件A。5、负压式膜清洗方式对两种膜组件的清洗效果不同。膜组件A清洗后瞬时膜通量随清洗时间的增加而出现小幅下降的现象;而膜组件B清洗后瞬时膜通量则随清洗时间的增加而出现小幅上升的现象。6、次氯酸钠在线反冲的膜清洗方式是一种比较理想的清洗方式,膜组件A的平均膜通量恢复率为78.7%,膜组件B的平均膜通量恢复率为65.4%。其对膜组件A的清洗效果优于膜组件B。更多还原

【Abstract】 As known, Beijing, a famous age-old capital, is one of the water quite deficient metropolis in the world. Deficiency of water resource has become a bottleneck for the continuable or sustainable development of economy in Beijing. Surburb of Beijing is both a natural ecological safeguard and main water source for the Capital. Therefore, treatment of wastewater in country area plays a more and more important role in protection of citys water source and water environment. Considering the practical situation and development requirement of Beijing, The aims of this thesis is to afford technical support for the reduction of wastewater drainage, pollution control of rivers effectively and control of riverhead, and overcome the crisis of water deficient in Bejing finally. There are two sets of membranes moulds to be tested in the subject, and the aim is to improve the traditional membrane bioreactor and constructed a new membrane bioreactor with gravity flow. The main results as follow:1. The results indicated that the pure water permeate flux, the membrane resistance and the permeate flux for membrane mould A (Material: PVDF, Diameter:0.54 mm, Aperture: 0.4μm, Membrane area: 9.0 m2) are 42.611[L·(m2·h)-1/KPa], 1.47(108m-1) and 11 L·(m2·h)-1. the pure water permeate flux, the membrane resistance and the permeate flux for membrane mould B (Material: PE, Diameter: 0.80 mm, Aperture: 0.2μm, Membrane area: 12.5 m2) are 40.839[L·(m2·h)-1/KPa], 2.66(108m-1) and 7.5 L·(m2·h)-1. The removal efficiency of CODcr and NH4+-N for the membrane mould A and the membrane mould B were over 80% and 60%.2. The permeate flux for membrane mould A increased with the increase of water gravity in the MLSS from 2000 mg/L to 3000 mg/L. The permeate flux for membrane mould A could be achieved the biggest permeate flux under the four given water gravities when the aeration intensity was 50 m3·(m2·h)-1. The weak effect of aeration intensity on permeate flux was small and the permeate flux decreased not significantly. The economical aeration intensity was 50 m3·(m2·h)-1 and the average permeate flux was 8.7 L·(m2·h)-1. The permeate flux for membrane mould B increased with the increase of water gravity. The effect of aeration intensity on the permeate flux for membrane mould B was not significant. The weak effect of aeration intensity on permeate flux was small when the aeration intensity was from 40 m3·(m2·h)-1 to 60 m3·(m2·h)-1and the permeate flux decreased not significantly. The economical aeration intensity was 40 m3·(m2·h)-1 and the average permeate flux for membrane mould B was 3.7 L·(m2·h)-1. The permeate flux for membrane mould A had good resistance membrane pollution properties and kept higher permeate flux. However, the permeater flux for membrane mould B remained to strengthen on the ability of resistance membrane pollution. Meanwhile, the effect of water gravity for membrane mould B was large. The maximum increasing rate of J/Δp for membrane mould B was 168.75% and the permeate flux for membrane mould A was only 16.95%.3. The economical aeration intensity was 40 m3·(m2·h)-1 for this membrane bioreactor with gravity flow. The average removal efficiency of NH4+-N, CODcr, and turbidity were 97.8%, 90.8% and 99.4%. Compared permeate flux and aeration intensity, the mould A was economical efficiency than the mould B, and the mould A was fit for membrane bioreactor with gravity flow.4. Aeration played a certain role in the scouring of membrane foulants but had no obvious effect on the cleaning of membrane pore fouling. After different aeration time, membrane mould A recovered 26.9%～39.8% flux of average flux in gravity flow while membrane mould B recovered 49.0%～70.0% flux of average flux in gravity flow which indicated that cleaning efficiency of membrane mould B was better than that of membrane mould A.5. The effect of minus pressure cleaning on the two membrane mouldes was different. After cleaned, instantaneous flux of membrane mould A appeared a slight decrease with the increase of cleaning time, whereas instantaneous flux of membrane mould B appeared a slight increase with the increase of cleaning time.6. Membrance cleaning way of NaClO online backwashing was a relatively ideal cleaning way. The average flux recovery ratio of membrane mould A and membrane module B were 78.7% and 65.4%.The cleaning effect of NaClO online backwashing on membrane mould A was better than membrane mould B.更多还原