RCEES OpenIR  > 环境水质学国家重点实验室
典型南方水源水强化混凝和优化工艺研究
Alternative TitleEnhanced Coagulation and Optimization Technique for Typical South-China Source Water
刘海龙
Subtype博士
Thesis Advisor汤鸿霄 ; 王东升
2005-12-01
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Discipline环境工程
Keyword强化混凝 预氧化 Enhanced Coagulation 臭氧 Pre-oxidation 消毒副产物 O3 聚合铝 Disinfection By-products Polyaluminum Chloride (Pacl).
Abstract消毒副产物(DBPs)的去除是当今饮用水安全的重大课题,强化混凝是控制DBPs前驱物的重要手段。本文对深圳原水的水质特征、混凝特征、强化混凝特征及其在预臭氧氧化条件下对混凝去除有机物的影响进行了系统的研究。建立了有机物分级表征方法,提出了强化混凝系统研究方法;针对中国典型南方水,研究了强化混凝特征及其影响因素,系统研究预臭氧对混凝的影响,发现混凝剂碱化度在预臭氧对混凝作用中的重要影响,并提出应针对水体有机物组成特性选择优化组合工艺。
研究、建立了较为适用的水体有机物特征分析表征方法,首次对深圳水库水体有机物分级表征,发现溶解性有机物(DOC)占总有机物(TOC)90%左右,DOC以小分子(1KD以下)、亲水性有机物为主,分别占60%和40%左右。通过烧杯试验和现场试验(中试试验或生产性试验),针对目标水体特点提出了强化混凝工艺要点:混凝剂选PACl2.5、pH值6.5~7.5和增加混凝剂投量50-100%。针对强化混凝带来的负面影响和当地水厂生产的实际需求,研究了有机高分子助凝剂的使用。针对目标原水,有机高分子助凝作用增大絮体等效粒径、增强絮体密实度、促进沉淀,有效降低浊度,抗冲击性能好;在低投药量阶段助凝明显,阳离子聚丙烯酰胺(PAM)可以降低主混凝剂投量30%。有针对性地解决了水厂跑矾花的实际问题,但对TOC去除助凝作用不显著。
运用PDA(Photometric Dispersion Analysis)、有机物分级表征技术和原子力显微镜表征技术系统研究了臭氧预氧化对混凝的作用,研究包括臭氧的投加量和接触时间、混凝剂的种类、水体有机物种类和分布等主要的影响因素;发现预臭氧对混凝影响程度和PACl碱化度(B)密切相关,B值越小Ala含量越多,影响程度越大。有机物与低聚态铝离子的结合是臭氧影响混凝效果的关键。臭氧助凝的影响从很大程度上取决于原水中有机物分子量分布,在DOC去除上主要取决于有机物或者有机物附着体的粒度大小以及分布特征。臭氧对有机物的矿化作用,及其降低分子量、增强亲水性的作用,这两者在DOC的变化上是相反的,最终DOC的处理效率取决于消长作用。有机物处理优化集成试验实现了药剂优化、工艺条件优化,预臭氧、强化混凝以及主臭氧、BAC优化组合工艺有效去除TOC和THMFPs,分别达到75%和80%以上,TOC从原水2.92ppm降低到出水中的0.5-0.7ppm,THMFP由230ppb降至50ppb左右;藻类去除达到85-90%,AOC显著增多(约一倍左右),出水溴酸盐有显著增加(11ng/L);余铝、甲醛等没有明显增多。
强化混凝和预氧化等工艺环节的优化组合,能有效地去除DBPs前驱物,控制DBPs的危害。
Other AbstractDisinfection By-Products (DBPs) have become an important topic to the safety control of drinking water. Enhanced coagulation is one of the important techniques to control DBPs. The thesis aimed at removing precursor of DBPs by using Enhanced Coagulation and optimizing of pre-ozonation and other downstream treatment processes.
Apparent molecular weight distribution (AMWD) and resin fractionation methods were established and first used in water of Shenzhen Reservoir, a typical South-China water. The results show that DOC composes major part of TOC, which takes up 90% of TOC. DOC less than 1k Dalton and the hydrophilic parts take up 60% and 40% respectively. Systematic investigation on enhancing removal of natural organic matter (NOM) using polyaluminum chloride (PACl) and polyacrylamide (PAM) were performed. Enhanced coagulation and applying polymer flocculant-aid were compared through jar tests and pilot tests. Raw water and settled water were characterized and fractionated by resin adsorption method. Major operation parameters were obtained which including the use of PACl with B value 2.5 as optimum coagulant, increasing of coagulant dosage by 50-100% and pH control to 6.5-7.5. Removal of TOC was improved by about 10% or more under such conditions. Floc diameters and capacity of settlement were improved clearly by using PAM as flocculant aid. PACl could be saved about 30% when PAM was used, which would maintain the same removal of turbidity. But coagulation aid effect was still not clear under local conditions.
Different inorganic polymer flocculants (IPFs)-polyaluminum chloride (PACl) with various B (OH/Al ratio) values were synthesized and applied to examine the effect of ozone on coagulation and the role of coagulant speciation as well. Formation and performance of flocs during coagulation processes were monitered using PDA (Photometric Dispersion Analyzer). And the apparent molecular weight distribution and resin fractionation method were performed to characterize molecular changes of aquatic organic matter (AOM) resulted from pre-ozonation. The results show that O3 exhibits complicated effects on organic matter coagulation depending largely on dosage of O3, characteristics of AOM and coagulant speciation. Interaction of ozone with AOM results in two effects: decomposition-mineralization of small AOM and desorption-decomposition of AOM adsorbed on particles. Complexation of Al ions and AOM is the key factor influencing coagulation following pre-ozonation.
Optimized designation of pre-ozonation, enhanced coagulation, oznation and BAC could greatly improve removals of TOC and THMFP, to 75% and 80% respectively. Thus DBPs could be controlled significantly.
Subject Area水处理工程
Language中文
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/665
Collection环境水质学国家重点实验室
Recommended Citation
GB/T 7714
刘海龙. 典型南方水源水强化混凝和优化工艺研究[D]. 北京. 中国科学院研究生院,2005.
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