【作者】 张硕；

【导师】 张玉先；

【作者基本信息】 同济大学 ， 市政工程， 2007， 博士

【副题名】气浮—生物接触氧化—沸石过滤

【摘要】 对于微污染水源水，常规工艺有时不能有效去除氨氮、COD_Mn等以满足日益严格的水质标准。结合我国国情，本课题基于小城镇科技发展重大项目（2003BAS08A17），开发出一种处理受污染水源水的集成技术，并研究去除机理和工艺参数，为多级保障饮用水安全提供技术途径。本研究将气浮工艺与生物膜反应器集成，以防止泥沙沉积影响生物处理和利用气浮水充氧效果，并将深度处理“O₃-GAC”工艺优化为“O₃-沸石-GAC”工艺。通过中试试验，研究运行参数对去除效果的影响，探讨反应动力学和去除机理。试验结果表明：高温下挂膜三周后，以COD_Mn和氨氮去除率与NO₂-N浓度变化规律判定生物膜成熟，反应器启动较快。随溶气罐压力和回流比增大，气浮出水DO浓度增长率高达50～350％，滤罐填充溶气填料时出水DO明显提高0.8～1.5mg／L。原水浊度90％左右由气浮去除。水力负荷或浊度负荷较大时，去除负荷提高3～4倍，组合工艺出水浊度低于2NTU。集成技术对叶绿素a去除率高于90％，且以气浮为主，滤罐为辅。藻类负荷或水力负荷较高时，除藻率均90％以上。AGP受温度和加药量影响明显，高温时超出低温20倍。高温下，COD_Mn总去除率大于80％，出水浓度低于3.0mg／L，低温时也在50％以上。有机物分子量分布试验表明，大分子有机物以气浮去除为主，小分子量则依靠接触区和滤罐生物作用降解。气浮出水UV₂₅₄和UV₄₁₀均显著下降，沸石过滤后两者降低也较明显。集成工艺沿程DOC去除率为26～38％，气浮和接触区的去除效果较好。各区出水的吸光值均在低波长紫外段，最终出水的190～235nm吸光值显著升高，235～400nm段则降低，与原水比较分子趋向饱和化和简单化。反应器性能评价上，对灰色关联度进行改进，结果表明气浮操作条件对除浊效果影响作用由大到小依次为进水浊度、回流比、加药量、水温和水力负荷。以量纲分析和π定理，推导出滤罐过滤性能指标。利用模糊数学权重计算方法，对工况进行评价表明，HRT为1.0h时，综合指标最小，去除效果和经济性较好。集成工艺接触区出水NH₃-N浓度显著下降50％以上，NO₂-N和NO₃-N浓度增长10倍左右。滤罐过滤后，NH₃-N去除近50％，NO₂-N浓度较低，NO₃-N则明显上升。进水增至1.5m³／h，接触区和滤罐的氨氮去除率仍达50％左右，前者受进水COD_Mn影响较大。高温期，氮挥发速率较大，风速4.5m／s时为4.8mgN／m²／d，动力学方程的K_N’和α较大。分析气态氮和微气泡碰撞频率公式可知，温度越高，气泡直径越大，气体分子量越小则碰撞速率越快。硝化速率和耗氧速率试验表明，旋转填料和沸石的硝化速率在1h内均高于1.0mg／L／h，之后则显著降低，上层旋转填料和下层的沸石硝化能力较强。下层旋转填料的耗氧速率为0.7743mgO₂／L／h，略高于上层，沸石的OUR则仅为接触填料50％左右。气浮去除机理方面，分形维数随加药量增加先变小后增大，投加15mg／L混凝剂时，分形维数较小，除浊效果较好。对于疏水絮体，气泡优先在絮粒表面析出，表面自由能下降较多，体系趋于稳定。析出气泡存在最小直径，上升时气泡变大以保持压力平衡。粘附率方程表明，增加气泡体积密度、提高絮粒和气泡附着几率和延长气浮时间可提高气浮去除效果。对气泡和絮体群体受力分析后，推导出上升速度和气泡最大吸附颗粒数。若颗粒数小于临界值，气泡将浮升。上升速度随附着的颗粒数变化，群体直径较大时则较快。滤罐溶气速率随时间延长而增长变缓。为了提高空气份额，可采取延长混合长度、增加湿润周界或提高摩擦系数。推导多组分空气溶解方程后发现，空气先溶解再释放后，氧气所占比例下降，滤罐空气层中可能积累O₂。由滤料吸附颗粒模型可知，反应常数受活化能、温度、粘附层厚度、沸石和颗粒粒径等影响，吸附率受被吸附物浓度影响较大。建立滤层生物降解模型后可知，水力负荷对反应速率常数影响较明显，膜龄受反冲洗强度和周期影响较大，稳态生物膜量为最大饱和度与衰减系数和增殖系数商的差值。工程应用上，对泥沙沉积、反冲洗、低温强化处理等方面分析后，提出了相应措施。除螺试验表明，预加氯、加次氯酸钠和水力冲刷等方法的效果不理想，排空后再反冲洗较好，而生物接触氧化区前置气浮则完全避免长螺。某水厂作为基金示范工程以集成技术处理微污染水源水，对浊度、藻类和氨氮效果良好，有效保障了饮用水水质安全。从理论和经验上，探讨了单基质负荷法、多因子拟合法、经验作图法和基质动力学法等四种设计方法。更多还原

【Abstract】 At present, the traditional water treatment techniques could not remove organic substance, ammonia nitrogen and other matters from the polluted raw water sometimes. Thus it is not enough for the strict drinking water quality standard. Based on the situation of china, an integrated technique was developed and removal mechanism and operation parameters were studied in this paper. The study gained financial support from State Small Towns Technology Development Project （grant 2003BA808A17）.In the study, dissolved air flotation process and microbe reactor were integrated, and zeolite was applied as the filling material for aerated filter to form "O3-zeolite-GAC" process. The operation conditions effect on the removal efficiency was studied in a pilot experiment. Then the reactor mechanism was discussed on the base of experiment.During biofilm cultivation, it took twenty days in the summer to grow up, judging by the criteria that NH3-N and COD_Mn removal rate stabilized and nitrite concentration in the effluent approaches low after fluctuation. With the increase of dissolved air pressure or pressurized water rate, DO in DAF effluent would grow 50～350% more than raw water. Dissolved oxygen of zeolite filter effluent raised 0.8 ～ 1.5 mg/L under the help of special contact filling.In the process, turbidity would be removed 90% by dissolved air flotation technique. Under high inlet flow or turbidity concentration, the turbidity could be removed more, which would be lower than 2.0 NTU in final effluent. Even under high algae concentration or flow, the chlorophyll removal efficiency was up to 90%, which was removed by DAF and filter. Algae growth potential was influenced by the temperature and coagulant and it would be enhanced in summer. The removal rate of COD_Mn would be 80% or so under high temperature, which about 50% in winter.Organic molecular weight experiment results showed that big molecular organics were removed by DAF and small those by microbe life action. UV₂₅₄ and UV₄₁₀ would be reduced by DAF and filter. DOC removal rate in any part of integrated process could be 26～38% The effluent absorbency was in the ultraviolet zone, which rose great in 190～235 nm and fell in 235～400 nm.In the dissertation, new method was introduced to revise grey weighted related degree calculation. The results displayed that factors ranging from great effect to low on turbidity removal were influent turbidity, pressurized water rate, coagulant, temperature and flow. Filter performance was evaluated by the index derived from theory and fuzzy mathematics. Furthermore, the performance index value was relatively small under 1.0 HRT, which resulted from short hydraulic retention time and favorable effluent quality.NH₃-N would decrease above 50% after treated by contact filling microbe film. However, NO₂-N and NO₃-N could increase 10 times. In the filter effluent, NH₃-N dropt about half with low NO₂-N concentration. Under 1.5m³/h, NH₃-N removal rate of contact part and filter could be more than 50% and the former was influenced by influent COD_Mn. In summer, the ammonia volatilization velocity could be 4.8 mgN/m²/d under wind speed 4.5m/s and kinetic constants were higher than in winter. Analyzing the equation on the contact velocity of ammonia and air bubble, the diameter would grow under high temperature and short space from water surface. According to small molecular weight,the velocity could be bigger.The tests results of nitrification showed that both nitrification rates of upper layer rotating fillings and zeolite were higher than 1.0 mg/L/h in an hour, and then obviously fell. Upper layer rotating fillings and low layer zeolite had better nitrification capacity. But the oxygen uptake rate（OUR） of under layer fillings was 0.7743 mgO₂/L/h, higher than that of upper ones. OUR of zeolites was only half of the fillings’.In the aspect of floatation removal theory, fraetal dimension decreased at first and then increased when coagulant dosage increased. When the dosage was 15 mg/L, fractal dimension was smaller and removal effect of turbidity was better. For hydrophobic flocs, air bubbles preferred occurring on their surfaces since surface free energy of system decreased largely and the whole flocculation system became stable. The air bubbles had minimum diameter and became larger to balance pressure in ascending. The equation of adhesion rate showed that augmenting the volume density of air bubbles, increasing the adhesion probability of flocs and air bubbles and lengthening floatation time could improve the removal effect by floatation. Analyzing the forces on air bubbles and flocs, the relation between ascending velocity and maximum adhesion quantity of flocs by air bubbles was deduced that when the floc number is smaller than critical value, air bubbles would ascend and the ascending rate could change with the number of flocs and increase with floc diameter.Air dissolution velocity increased more slowly with time. Lengthening length of mixing tank, increasing wetted perimeter and improving frictional coefficient were efficient measures to enhance air dissolution. By deduced air dissolution equation, it was found that when air dissolved and then released the proportion of oxygen would decrease and the air space in the dissolved air vessel would probably accumulate oxygen. The adhesion model of filter material indicated that the reaction constant was influenced by activation energy, temperature, thickness of adhesion layer, zeolite and particle diameter. Adherence rate was largely influenced by adsorbate concentration. Biodegradation model of the filter showed that reaction rate was obviously affected by hydraulic loading and membrane age by backwash rate and filter runtime. Stable biofilm quantity was the difference value between maximum saturation and coefficient of quotient of attenuation to propagation.Some problems such as silt deposit, back wash and enhanced treatment in low temperature and their measures were discussed. The snail removal experiment revealed that the removal was not effective by prechlorination, sodium hypochlorite or hydraulic wash, but it would be better by back wash after emptying. However by putting floatation before biological contact process, there were never any snails. When this integrated process was applied to treat heavily polluted water in a plant as a model project, the removal effects of turbidity, alga and ammonia nitrogen were satisfactory that efficiently guaranteed the security of drinking water. This dissertation discussed four design methods on theory or experience that are substrate loading method, multiple factor fitting method, experience drawing method and substrate dynamics.更多还原