臭氧-活性炭工艺去除饮用水中典型内分泌干扰物试验研究

通过对臭氧-活性炭工艺和活性炭吸附等温线的研究,探讨了臭氧-活性炭工艺去除饮用水中微量典型内分泌干扰物的可行性.壬基酚(NP)、辛基酚(OP)和双酚A(BPA)被选作目标物质.研究发现臭氧氧化能去除30%以上的NP、OP和BPA;活性炭对NP、OP和BPA也有良好的去除效果,在空床停留时间4～12 min条件下能完全去除水中未被臭氧氧化的NP、OP和BPA;吸附等温线的数据可以用Freundlich公式拟合,并用来估算活性炭的饱和时间.试验证明臭氧-活性炭工艺是去除饮用水中微量典型内分泌干扰物的有效方法.     

臭氧活性炭工艺去除饮用水中CODMn的应用试验

通过臭氧活性炭工艺去除饮用水中COD     

臭氧活性炭工艺去除饮用水中COD_(Mn)的应用试验

通过臭氧活性炭工艺去除饮用水中CODMn 的应用试验 ,探讨了工艺参数的选择对CODMn去除效果的影响。在此基础上 ,提出了臭氧活性炭二级串联工艺布置方式 ,试验结果表明能大幅度提高CODMn的去除率。     

改性蜂窝陶瓷催化臭氧氧化净水效能中试研究

通过中试考察了改性蜂窝陶瓷催化臭氧氧化(催化氧化)—活性炭过滤的净水效果,并与臭氧—活性炭工艺进行比较。试验条件下蜂窝陶瓷催化剂在静态和动态条件下均不会促进气体向水中的传质;静态条件下催化氧化对水中有机物的去除效率比臭氧单独氧化高;动态试验中,催化氧化对UV254的去除率高于臭氧氧化,但对TOC的去除没有优势,与臭氧氧化相比催化氧化有利于后续活性炭对有机物的去除。GC/MS测定表明,催化氧化及其后续活性炭出水中半挥发性有机物种类分别比臭氧单独氧化少9%和32%。经Ames试验发现,两种氧化及其后续活性炭处理后水的致突变活性均有微小增加。     

饮用水处理工艺去除两种典型内分泌干扰物的性能

研究了水中两种典型内分泌干扰物———双酚A(BPA)和邻苯二甲酸二甲酯(DMP)在饮用水常规处理、臭氧活性炭和微曝气活性炭深度处理中试工艺中的去除性能。研究发现,饮用水常规处理工艺对BPA和DMP的去除效果有限,进水浓度为200~300μg/L条件下经过混凝、沉淀和砂滤后,BPA和DMP的去除率分别仅为25.38%和13.29%。臭氧活性炭深度处理工艺能有效去除BPA和DMP,但二者在该工艺中的去除特性有所不同:水中BPA经过臭氧氧化后几乎被全部去除,后续的生物活性炭处理单元作用较小;但臭氧氧化仅可部分去除DMP,大部分靠后续生物活性炭柱去除。微曝气活性炭深度处理工艺也能有效去除BPA和DMP,对二者的去除主要靠微曝气活性炭柱的作用,其效果略优于臭氧投加量为0条件下的臭氧活性炭柱,这说明微曝气活性炭柱存在较多的特定降解菌。通过静态吸附试验发现,臭氧活性炭柱和微曝气活性炭柱内活性炭对BPA和DMP的最大吸附容量均远小于新炭,同时臭氧活性炭柱内活性炭吸附容量略高于微曝气活性炭柱。     

饮用水深度净化工艺现场对比试验

考察了实际生产规模的臭氧粒状活性炭工艺以及小型超滤、纳滤、反渗透膜法两种典型饮用水深度净化工艺的处理效果。试验结果发现臭氧活性炭工艺具有优良、稳定的去除有机污染物功能,而孔径较小的活性炭纤维除污染效果并不好,臭氧氧化出水、超滤出水再用压缩活性炭进行吸附处理对有机物的去除效率要比直接处理原水高。超滤膜除有机物效率不高,而反渗透和纳滤膜在较好地去除水中有机物的同时,也去除了水中绝大部分无机物,出水有机物和无机物浓度都比较低。     

东太湖水源臭氧-活性炭工艺中溴酸盐生成及其影响因素

东太湖水中溴离子含量较高,采用臭氧-活性炭工艺很可能会导致出厂水中溴酸盐超标。研究了以东太湖为水源的吴江第二水厂各处理工艺中溴酸盐的生成情况以及影响因素,结果表明,原水中的溴离子在臭氧氧化过程中主要产物为溴酸盐,分析了影响水厂溴酸盐生成的主要因素为水温、臭氧浓度和有机物含量。利用小试进一步研究了这些因素对臭氧氧化原水过程中溴酸盐生成的影响规律。研究结果表明,随着臭氧浓度的增加,溴酸盐生成量逐渐增多,在臭氧浓度达到2.2mg/L时溴酸盐生成量接近限值10μg/L,在相同的臭氧浓度下,较短的接触时间、高温以及高氨氮会减少溴酸盐的生成。     

溴酸盐和溴离子在活性炭上的竞争吸咐研究

高溴离子原水经臭氧氧化后同时存在溴酸盐和溴离子。考察了溴酸盐和溴离子的单组分和双组分活性炭吸附等温线及吸附动力学曲线。研究表明,溴酸盐和溴离子同时存在时会产生竞争吸附,活性炭对溴酸盐的吸附速率大于溴离子。应用动力学模型对双组分竞争吸附进行了拟合,双组分条件下活性炭对溴酸盐和溴离子的吸附过程用Langmuir动力学模式描述是合适的。活性炭对溴酸盐和溴离子的去除受pH和有机物的影响较大,较低pH和较低的有机物含量有利于活性炭的吸附。     

臭氧催化氧化改善水质安全性指标中试与生产性研究

从水的生物稳定性、遗传毒性、颗粒物去除、臭氧氧化副产物以及催化剂的稳定性等方面研究了臭氧催化氧化-生物活性炭技术在净水处理过程中的安全性问题.结果表明,催化剂具有优良的物理化学稳定性,能够催化臭氧氧化进一步控制AOC及其前质,减小了活性炭的污染物负荷;与生物活性炭联用可以明显减小有害有机物穿透水处理工艺的能力,进一步消减了水的遗传毒性;联用工艺可以显著地去除水中与致病原生动物相关性极大的2～10 μm颗粒物,进一步提高了饮用水的卫生安全性;催化剂对剩余臭氧的消减抑制了BrO-3生成.     

东太湖水源臭氧-活性炭工艺消毒副产物的生成规律与控制

对以东太湖水为水源的臭氧—活性炭处理工艺和常规处理工艺净水厂的消毒副产物生成情况进行了一年的检测,研究了臭氧—活性炭和常规处理工艺各处理单元对消毒副产物生成势的作用情况。结果表明,臭氧—活性炭和常规处理工艺的出厂水中均含有三卤甲烷、卤乙酸、卤乙腈等消毒副产物;与常规处理工艺相比,臭氧—活性炭处理工艺出水中的消毒副产物种类少、总量低,但三溴甲烷、二溴乙酸的生成量高;臭氧氧化能使消毒副产物生成势提高,砂滤工艺对消毒副产物生成势的去除效果稳定,混凝—沉淀工艺比其他工艺单元对消毒副产物生成势的去除效果好,活性炭工艺在夏季对消毒副产物生成势的处理效果比其他季节好。     

臭氧-活性炭深度处理滦河水的试验研究

对滦河水进行O3-GAC工艺深度处理中试研究表明O3-GAC能在较长时间内保持对水中有机物的去除,CODMn的平均去除率为60.19%;TOC的平均去除率为64%;UV254的平均去除率为70.41%;NH3-N的平均去除率为53.83%;对水中的浊度和色度都有明显的去除效果,尤其臭氧化对改善难生物降解有机物的可生化性有十分显著的作用;O3-GAC能有效地去除饮用水中的有害、有毒物质,提高饮用水的安全性.     

臭氧氧化工艺溴酸盐控制中试研究

通过1m3/h的中试装置研究了臭氧氧化工艺处理引黄水库水时溴酸盐控制技术。结果表明,在臭氧投加量为1.5mg/L时,臭氧氧化后溴酸盐产生量为0.006mg/L,活性炭过滤出水溴酸盐为0.002mg/L;在相同臭氧投加量条件下,降低原水pH、投加高锰酸钾和过氧化氢后溴酸盐生成量分别减少了50%、33%和100%,活性炭后出水中均未检出溴酸盐,同时提高了有机物去除率。     

The basics of oxidants in water treatment. Part B: ozone reactions.

The oxidation of organic and inorganic compounds during ozonation can occur via ozone or OH radicals or a combination thereof. Ozone is an electrophile with a high selectivity. The reactions of ozone with inorganic compounds are typically fast and occur by an oxygen atom transfer reaction. Organic micropollutants are oxidised with ozone selectively. Ozone reacts mainly with double bonds, activated aromatic systems and non-protonated amines. The kinetics of direct ozone reactions depend strongly on the speciation (acid-base, metal complexation). The reaction of OH radicals with the majority of inorganic and organic compounds is nearly diffusion-controlled. The degree of oxidation by ozone and OH radicals is given by the corresponding kinetics and the ratio of the concentration of the two oxidants. Product formation from the ozonation of organic micropollutants has only been established for a few compounds. Numerous organic and inorganic ozonation disinfection/oxidation byproducts have been identified. The byproduct of main concern is bromate, which is formed in bromide-containing waters. A low drinking water standard of 10 microgL(-1) has been set for bromate. In certain cases (bromide > approximately 50 microgL(-1)), it may be necessary to use control measures to lower bromate formation (lowering of pH, ammonia addition, chlorination-ammonia process).     

饮用水深度处理中活性炭的筛选试验研究

目前国内生产的适合于不同水源水质的饮用水处理的活性炭品种较多,性能不一。研究表明,用作饮用水深度处理的活性炭的选炭工作至关重要,要针对所处理的水质进行吸附等温线测定、动态吸附柱试验和对实际有机物的去除效果试验测定后经综合分析、合理评定才能选择确定合适的活性炭,而不能单采用碘值及亚甲蓝值。     

臭氧生物活性炭处理微污染水源水的工艺及其发展

介绍了臭氧生物活性炭处理微污染水源水的基本原理、工艺流程,以及国内外该技术的研究和发展状况,提出了应用该法时需注意的一些问题。研究表明,臭氧生物活性炭净水技术能够有效地去除水中的有机物、氨氮,对水中的无机还原性物质等也有很好的去除效果,并且能有效地降低出水致突变活性,保证饮用水安全,是一种值得推广的净水技术。     

臭氧活性炭深度处理工艺除藻效能研究

通过中试除藻试验,研究了臭氧活性炭深度处理工艺的除藻效能。结果表明,经过预臭 氧化和常规工艺处理后,深度处理工艺可再去除67％的含藻量。工艺参数:臭氧投加量2 mg／L,接 触时间15 min,活性炭滤池滤速10 m／h,停留时间12 min。探讨了预臭氧化和深度处理两种组合工 艺的除藻机理和影响因素。     

Advanced treatment of benzothiazole contaminated waters: comparison of O3, AC, and O3/AC processes.

Benzothiazole (BT) is a toxic and poorly biodegradable contaminant, usually found in wastewater from rubber related applications. This compound could be effectively eliminated using advanced treatment processes. This paper compares experimental results on detoxification systems based on ozone oxidation, activated carbon adsorption, and simultaneous adsorption-oxidation using ozone in the presence of activated carbon. The effect of pH (2-11), and the presence of radical scavengers (tert-butyl alcohol and sodium carbonate) on process rates and removal efficiencies are assessed at laboratory scale. The experimental system consisted of a 1 L differential circular flow reactor and an ozone generator rated at 5 g O3/h. Results show that ozone oxidation combined with activated carbon adsorption increases the overall BT oxidation rate with respect to the ozonation process and activated carbon adsorption. In the presence of free radical scavenger, only a 44% reduction in BT removal rate is observed in the simultaneous treatment, as compared with 72% when ozonation treatment is used, suggesting that BT oxidation reactions mainly take place on the activated carbon surface.     

Efficient taste and odour removal by water treatment plants around the Han River water supply system.

Seven major water treatment plants in Seoul Metropolitan Area, which are under Korea Water Resources Corporation (KOWACO)'s management, take water from the Paldang Reservoir in the Han River System for drinking water supply. There are taste and odour (T&O) problems in the finished water because the conventional treatment processes do not efficiently remove the T&O compounds. This study evaluated T&O removal by ozonation, granular activated carbon (GAC) treatment, powder activated carbon (PAC) and an advanced oxidation process in a pilot-scale treatment plant and bench-scale laboratory experiments. During T&O episodes, PAC alone was not adequate, but as a pretreatment together with GAC it could be a useful option. The optimal range of ozone dose was 1 to 2 mg/L at a contact time of 10 min. However, with ozone alone it was difficult to meet the T&O target of 3 TON and 15 ng/L of MIB or geosmin. The GAC adsorption capacity for DOC in the three GAC systems (F/A, GAC and O3 + GAC) at an EBCT of 14 min is mostly exhausted after 9 months. However, substantial TON removal continued for more than 2 years (>90,000 bed volumes). GAC was found to be effective for T&O control and the main removal mechanisms were adsorption capacity and biodegradation.     

Removal of bromate and assimilable organic carbon from drinking water using granular activated carbon.

This study investigated the feasibility of using granular activated carbon (GAC) to remove bromate ion (BrO3-) and assimilable organic carbon (AOC) from drinking water through a rapid small-scale column test (RSSCT) method and a pilot-scale study. Results from RSSCT indicated that the GAC capacity for BrO3- removal was dependent on the GAC type, empty bed contact time (EBCT), and source water quality. The GAC with a high number of basic groups and higher pHpzc values showed an increased BrO3- removal capacity. BrO3- removal was improved by increasing EBCT. The high EBCT provides a greater opportunity for BrO3- to be adsorbed and reduced to Br- on the GAC surface. On the other hand, the presence of dissolved organic carbon (DOC) and anions, such as chloride, bromide, and sulfate, resulted in poor BrO3- reduction. In the GAC pilot plant, a GAC column preloaded for 12 months achieved a BrO3- and AOC removal range from 79-96% and 41-75%, respectively. The BrO3- amount removed was found to be proportional to the influent BrO3- concentration. However, the BrO3- removal rate apparently decreased with increasing operation time. In contrast, the AOC apparently increased during the long-term operation period. This may be a result of the contribution due to new GAC being gradually transformed into biological activated carbon (BAC), and the bacterial biomass adsorbed on GAC surface hindering BrO3- reduction by GAC either by blocking pores or adsorbing at the activated sites for BrO3- reduction.     

Removal of geosmin and 2-methylisoborneol by biological filtration.

The quality of drinking water is sometimes diminished by the presence of certain compounds that can impart particular tastes or odours. One of the most common and problematic types of taste and odour is the earthy/musty odour produced by geosmin (trans-1, 10-dimethyl-trans-9-decalol) and MIB (2-methylisoborneol). Taste and odour treatment processes including powdered activated carbon, and oxidation using chlorine, chloramines, potassium permanganate, and sometimes even ozone are largely ineffective for reducing these compounds to below their odour threshold concentration levels. Ozonation followed by biological filtration, however, has the potential to provide effective treatment. Ozone provides partial removal of geosmin and MIB but also creates other compounds more amenable to biodegradation and potentially undesirable biological instability. Subsequent biofiltration can remove residual geosmin and MIB in addition to removing these other biodegradable compounds. Bench scale experiments were conducted using two parallel filter columns containing fresh and exhausted granular activated carbon (GAC) media and sand. Source water consisted of dechlorinated tap water to which geosmin and MIB were added, as well as, a cocktail of easily biodegradable organic matter (i.e. typical ozonation by-products) in order to simulate water that had been subjected to ozonation prior to filtration. Using fresh GAC, total removals of geosmin ranged from 76 to 100% and total MIB removals ranged from 47% to 100%. The exhausted GAC initially removed less geosmin and MIB but removals increased over time. Overall the results of these experiments are encouraging for the use of biofiltration following ozonation as a means of geosmin and MIB removal. These results provide important information with respect to the role biofilters play during their startup phase in the reduction of these particular compounds. In addition, the results demonstrate the potential biofilters have in responding to transient geosmin and MIB episodes.