【作者】 陈涛；

【导师】 赫俊国；

【作者基本信息】 哈尔滨工业大学 ， 建筑与土木工程（专业学位）， 2018， 硕士

【摘要】 我国长江下游地区全年气温和降雨量变化明显,其地表水水源受外界环境的影响较大,水质呈现冬季部分时段低温低浊、夏季浊度突变的特性,同时受上游城市排放的生活污水、工业废水及沿线的农业灌溉等的影响,原水中耗氧量较高,尤其当浊度突变时,对现有净水厂工艺造成较大的冲击,难以保障供水的安全性。本论文以江阴小湾水厂原水为研究对象,开展了强化混凝工艺研究,通过对近年来原水的水质变化规律进行分析,确定长江下游地区原水水质特性,开展混凝动力学特性研究与参数优化、混凝剂种类及投加量、助凝剂最佳投加量及投加点确定小试试验,并在此基础上,开展强化混凝中试效能及抗冲击负荷能力试验研究,为工程实施提供参数,并以小湾水厂西区改建工程为依托进行经济性分析。通过对近几年小湾水厂原水的水质变化规律分析表明,长江江阴段原水水质全年变化较大,温度及浊度季节性变化明显,在冬季部分时间存在低温低浊的现象,而在夏季浊度较高,极端天气下又会出现浊度突变;原水呈弱碱性,pH全年保持在7.9左右,变化幅度较小;氨氮浓度较低,通常保持在0.5mg/L以下;耗氧量较高,全年平均耗氧量为6mg/L左右。混凝动力学试验确定了混合及絮凝过程中的最佳动力学参数,最终确定混合过程中最佳转速为300r/min,时间为45s;絮凝阶段分为一级絮凝和二级絮凝,一级絮凝的最佳转速为100r/min,时间为5min;二级絮凝的最佳转速为60r/min,时间为10min。混凝剂的优化比选及助凝剂最佳投加量及投加点试验表明,除残余铝和残余铁两项指标外,聚合硫酸铝铁和聚合氯化铝铁均表现出了优于其他混凝剂的处理效果,二者的最佳投加量范围为60-70mg/L;助凝剂的最佳投加量为1.0mg/L,最佳投加点为混合结束后5min投加,即一级絮凝结束后立即投加。强化混凝中试试验对聚合硫酸铝铁和聚合氯化铝铁的投加量、助凝剂的投加量和投加点进行了进一步的优化,聚合氯化铝铁对于浊度及剩余颗粒总数的去除效果较好,出水水质达到了1.52NTU,而聚合硫酸铝铁对于去除耗氧量的效果较好,其去除率达到了65%,二者均在65mg/L时达到最佳去除效果;当混凝剂与助凝剂联用时,在15#竖井投加1.1mg/L阴离子型PAM可以将出水浊度、剩余颗粒总数和耗氧量分别控制在0.3NTU、31个/mL和2.7mg/L以下。中试抗冲击负荷试验表明,水量和水质变化均会导致出水水质下降,不同的药剂组合其变化程度不同。混凝剂与助凝剂联用的出水效果较单独投加混凝剂的出水效果好,聚合硫酸铝铁+PAM的药剂组合在面临冲击负荷时出水水质较聚合氯化铝铁+PAM的变化幅度更小,出水水质更平稳,当水量在0.75-1.25倍设计水量范围内变化时,其沉后出水浊度及剩余颗粒总数均能保持在0.7NTU和70个/mL以下,耗氧量保持在3mg/L以下;当原水浊度在250NTU以下时,其出水浊度及剩余颗粒总数均能保持在1.0NTU和100个/mL以下,耗氧量保持在3mg/L以下,只有当原水浊度高于250NTU时出水水质恶化程度才会加剧。以此为依据,确定聚合硫酸铝铁为最适合原水水质的混凝剂。强化混凝实际工程以江阴小湾水厂西区改建工程为依托,在对其常规处理工艺(混合、絮凝、沉淀、过滤)、过滤水回用池、清水池、排泥水处理工艺等进行工艺、建筑、电气、结构及自动化控制等进行了设计建造的基础上,对水厂原水、改造工程沉淀池出水、原有东区工艺沉淀池出水进行两个月的水质分析,结果发现,聚合硫酸铝铁+PAM的药剂组合比单独投加聚合氯化铝的出水效果更好,其出水中浊度及剩余颗粒总数值低于原有工艺出水的50%以上,耗氧量去除率提高20%左右,同时出水水质波动较小,抗冲击负荷能力强。工程实施表明,该工艺处理长江下游原水总投资为31381.23万元,运行成本0.47元/m~3,单位经营成本为0.28元/m~3。更多还原

【Abstract】 The temperature and rainfall in the downstream area of the Yangtze River in our country have obvious changes throughout the year.The surface water sources in this area are greatly affected by the external environment.The water quality shows low temperature and low turbidity in winter and turbidity mutation in summer.Meanwhile,contaminated by the domestic sewage discharged from the upstream cities,industrial wastewater and agricultural irrigation along the line,the consumption of oxygen in the raw water is high,especially when the turbidity is abrupt,causing a great impact on the process of water purification plant,which makes it difficult to guarantee the safety of water supply.In this paper,the raw water of Jiangyin Xiaowan water purification plant is taken as the research object to carry out the research of strengthening coagulation process.The characteristics of raw water quality in the downstream area of the Yangtze River are analyzed by analyzing the variation regularity of raw water quality in recent years.And then the coagulation kinetics characteristics and parameters optimization,coagulant types and dosage,the best dosage of coagulant aid and dosage point were studied through batch tests.On this basis,the pilot study of strengthen coagulation efficiency and impact of load capacity were carried out,to provide parameters for the project implementation.The full scale study of strengthening coagulation and the economic analysis was based on the reconstruction project of west bay in Xiaowan water purification plant.Through the analysis of water quality changes of raw water in Xiaowan water plant in recent years,it was shown that the quality of raw water in Jiangyin section of Yangtze River changes greatly throughout the year.Seasonal changes of temperature and turbidity are obvious,and low temperature and low turbidity occur in part of winter.Turbidity in summer is high and changeable under extreme weather.The raw water is weakly alkaline while the pH is around 7.9 throughout the year,with a small change range.The ammonia nitrogen concentration is relatively low,usually below 0.5mg/L.However,the oxygen consumption value is high,about 6.0 mg/L all over the year.The optimum kinetic parameters in the mixing process and flocculation were determined by the coagulation kinetics tests.The optimum speed of the mixing process was 300 r/min and the duration was 45s.The flocculation stage was divided into primary flocculation and secondary flocculation.The optimal primary flocculation speed was 100 r/min,lasting for 5min and the optimal secondary flocculation speed was60 r/min,lasting for 10min.The tests of optimum coagulant,best dosage and dosing point showed that both polymeric aluminum ferric sulfate and polymeric aluminum ferric chloride showed better treatment efficiency than others except for the residual aluminum and residual iron.The best dosage of both were in the range of 60-70 mg/L and the best coagulant aid dosage was 1.0mg/L,dosing at the end of 5min after mixing,that is,immediately after the primary flocculation.The pilot tests of strengthen coagulation studied the dosage of the polymerization of aluminum and aluminum ferric chloride.The amount of coagulant aid and its dosing points were further optimized.The results showed that aluminum ferric chloride had a better removal efficiency for turbidity and the total number of remaining particles,with an effluent water quality of 1.52NTU.However,the polymerized ferric sulphate was better for oxygen removing and the removal rate reached 65%.Both of which reached the best removal efficiency at 65mg/L.When the coagulant and coagulant aid were used in combination,the addition of 1.1mg/L anionic PAM in 15#shaft can control the effluent turbidity,total residual particles and oxygen consumption at 0.3NTU,31/mL and 2.7mg/L or less.The impact load test showed that changes in water quantity and quality will both lead to a decline in effluent quality,but different combinations had different degrees of changes.The quality of effluent treated by the combination of coagulant and coagulant aid was better than that of coagulant alone.The effluent quality of polymerized ferric sulphate+PAM was higher than that of aluminum ferric chloride+PAM combination while facing with impact loading.The amplitude is smaller and the water quality is more stable.When the water volume changes within the range of 0.75-1.25 times of the designed water volume,the turbid water after sedimentation and the total number of remaining particles can be maintained below 0.7 NTU and 70/mL,and the oxygen consumption remained below 3mg/L.When the raw water turbidity was below 250NTU,the water turbidity and the total number of remaining particles can be maintained at 1.0NTU and 100/mL or less and the oxygen consumption remained below 3mg/L.Only when the original water turbidity wass higher than 250NTU,the deterioration of water quality will be aggravated.Based on this,it is determined that the poly-ferric aluminum sulfate is the most suitable coagulant for the raw water.The full scale strengthen coagulation test was carried out based on the reconstruction project of the Western Area of Jiangyin Xiaowan water purification plant.After the design and construction of the building,electrical,structural and automatic control for conventional treatment(mixing,flocculation,sedimentation and filtration),filtration of reuse water pool,clear water tank and discharged sludge water treatment process,the water quality of raw water,the effluent from the sedimentation tank of the reconstruction project and the effluent from the former eastern sedimentation tank were analyzed.As a result,it was found that the combination of polymeric aluminum sulfate+PAM was better than that of polyaluminum chloride alone.The turbidity and residual particles in the effluent were lower than 50% of the original effluent and the removal of oxygen was increased by about 20% at the same time.The quality of the effluent was less fluctuated and the capability of anti-impact load was stronger.The project implementation showed that the total investment of the process for raw water in the downstream area of the Yangtze River was 313,812,300 Yuan.The operation cost was0.47 Yuan/m~3,and the unit operating cost was 0.28 Yuan/m~3.更多还原