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。     

高藻期去除水中微量有机物的效果研究

研究不同预处理措施和深度处理单元对微量有机物的去除效果.通过中试研究,发现预氧化措施能够很明显地提高微量有机物的去除效果:投加臭氧的滤后出水中烃类、杂环烃、多环等有机物明显减少;高锰酸盐复合药剂(PPC)的助凝效果也使得滤后出水中有机物的种类降低了51%;PPC和臭氧联合预氧化的效果高于二者的单独预氧化方式;氯胺也可以提高对烃类、杂环烃类、醇酚以及一些未知的有机物的去除.对于深度处理来说,虽然臭氧活性炭后出水的有机物种类有一定程度的减少,但是GC/MS峰面积却有一定程度的增加,必须增加合适的消毒措施才能提高工艺出水的安全性能.     

Cu/Al2O3 催化臭氧氧化降解水中甲草胺的研究

研究了在Cu/Al2O3存在下臭氧氧化降解水中一种具有内分泌干扰作用的有机污染物--甲草胺的效能及主要影响因素.研究证明,Cu/Al2O3具有明显的催化臭氧氧化效能.对催化臭氧氧化降解前后水的TOC、电导及内分泌干扰活性等指标进行的测定结果表明,在Cu/Al2O3催化剂的作用下,反应溶液的TOC比O3单独氧化处理的TOC有更大程度的降低,即对甲草胺的矿化程度大大提高;矿化程度的提高使溶液的电导有所提高进而促进对甲草胺的处理.催化臭氧氧化处理后水的内分泌干扰活性比非催化过程的有明显降低,说明Cu/Al2O3催化剂可有效去除甲草胺的中间氧化产物,能彻底去除水中甲草胺这种内分泌干扰物质.     

载锰氮化碳催化臭氧法降解水中草酸研究

草酸是废水中多种有机物氧化降解的中间产物,与臭氧反应速率很低,难以直接氧化去除。本研究通过热解法煅烧不同摩尔比例的三聚氰胺与醋酸锰(Ⅲ)二水合物,制备出不同负载量的载锰氮化碳催化剂,并研究了不同条件下载锰氮化碳催化臭氧法对草酸的降解效果,考察三聚氰胺与醋酸锰摩尔比、催化剂投加量、p H值、臭氧浓度等因素以及叔丁醇对草酸去除效果的影响。实验结果表明:相对于单独臭氧氧化而言,载锰氮化碳催化臭氧法可以极大的提高草酸的去除率,在投加0.15 g/L三聚氰胺与醋酸锰20∶1的催化剂后,草酸在60 min的TOC去除率可达到89.1%。叔丁醇加入对草酸的去除率影响较小,表明·OH在载锰氮化碳催化氧化草酸的过程中起作用但不是唯一因素。     

催化臭氧化——一种有前景的水处理高级氧化技术

介绍了均相和非均相催化剂增加臭氧氧化去除水溶液中有机物的效率 ,催化臭氧化能够氧化或降解单独臭氧不能氧化或降解的难降解有机物 ,减少后续氯化消毒工艺所形成消毒副产物如三氯甲烷等的含量     

臭氧-上向流生物活性炭-砂滤工艺长期运行效果研究

分析了臭氧-上向流生物活性炭-后置砂滤组合工艺对有机物的去除效果,考察了不同进水浊度对组合工艺运行效果的影响,分析了臭氧氧化池溴酸盐生成量。结果表明,组合工艺可以承受3.0~7.5NTU浊度变化的冲击;长期运行结果显示,组合工艺对有机物指标有较好的去除效果,较高的温度有利于水中有机污染物的去除;臭氧进水浊度小于4 NTU时,组合工艺出水中CODMn、UV254和TOC的含量分别为1.25mg/L、0.017cm~(-1)、1.539mg/L,组合工艺出水溴酸盐长期均低于5μg/L,符合国家水质标准的要求。     

连续流催化臭氧氧化污水处理厂尾水效能研究

为实现城市污水处理厂尾水中残留有机物的进一步削减,降低其在环境中的危害,以钛硅分子筛TS-1负载铜和钇(Cu/Y-TS-1)为催化剂,研究连续流催化臭氧氧化深度处理城市污水处理厂尾水的效能,并考察了臭氧投加量及停留时间对尾水处理效果的影响。结果表明:连续流运行条件下,Cu/Y-TS-1催化臭氧氧化不仅能够有效去除尾水中的有机物,还可以进一步控制水中氮素的污染。在停留时间30 min、臭氧通量106.3 mg/min、臭氧流速1 L/min、Cu/Y-TS-1催化剂30g/L条件下,COD、溶解性有机碳(DOC)及NH_3-N分别由进水浓度53.1mg/L、16.7mg/L和7.34mg/L降低到19.5 mg/L、8.8 mg/L和2.4 mg/L。与单独臭氧氧化相比,COD、DOC和NH3-N分别提高了16.1%、21.3%和51.1%。臭氧投加量的增加及停留时间的延长有利于有机物和NH3-N的去除。     

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。     

强化混凝超滤组合工艺对有机污染物去除效能的研究

为了进一步提高水质处理效果,采用强化混凝超滤的组合工艺对湖水进行处理,考察该组合工艺对有机物的去除效能,及影响有机物去除效能的因素。试验结果表明:①强化混凝超滤组合工艺对原水浊度的去除效果较好,对TOC和UV254的去除效果也明显优于传统水处理工艺;②原水中UV254含量的波动,对UV254的去除率和滤后水UV254含量影响并不大。原水中TOC含量的波动,对TOC的去除率有很大的影响,对滤后水TOC含量的影响并不大。TOC的去除率普遍高于UV254的去除率;③根据原水和滤后水SUVA值的变化发现,强化混凝超滤组合工艺对亲水性有机物的去除率大于该工艺对疏水性有机物的去除率。在一定范围内,pH的变化对TOC和UV254去除率变化趋势相反。     

预氧化强化去除滤后水中颗粒物中试研究

中试研究了几种预氧化工艺对低温低浊高有机物地表水体中颗粒物的强化去除效果。试验结果表明,常规工艺滤后水中的颗粒数较高,经高锰酸盐复合药剂(PPC)预氧化,预氯／氯胺化以及PPC与氯／氯胺联合预氧化后,滤后水中2～15μm范围内的颗粒物大幅减少,颗粒总数分别减少了36．4％,69．4％,55．2 ％,同时过滤出水颗粒数波动较小,工艺运行的稳定性明显提高,探讨了预氧化控制颗粒物的机理。     

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water.

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.     

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.     

Particle separation as a pretreatment of an advanced drinking water treatment process by ozonation and biological activated carbon

The role of particle separation on the performance of ozone-biological activated carbon (BAC) was evaluated based on the analyses of the fate of organic substances in the process. Pilot plant studies were carried out using eutrophic lake water as raw water. The ozonation not only converted refractory organic matter into biodegradable matter but also particulate organic carbon (POC) into dissolved organic carbon (DOC). Total decrease in adsorbable and non biodegradable DOC fraction (ADOC) after ozonation was only 1690 of the influent into the biofiltration process followed by ozonation. However, the ozone-BAC process before membrane separation could reduce organic loading to membrane system. The smaller loading to microfiltration will result in long intervals of back washing and less frequent membrane fouling. Membrane separation before ozonation removed not only POC but also a part of DOC and could prevent dissolution of POC during ozonation. The decreases in ADOC by membrane and ozonation were 20% and 37% of the influent ADOC, respectively. The total decrease in ADOC for membrane process followed by ozonation was 57%. The separation of particulate matter will decrease loading of ADOC onto BAC significantly and, therefore, will extend service life of BAC.     

Classification of algogenic organic matter concerning its contribution to the bacterial regrowth potential and by-products formation

The bacterial regrowth potential (BRP) and the by-products formation potential after the disinfection (DBP) are parameters recognized to be influenced by the origin of organic matter dissolved in water. A significant difference of the impact of humic compounds and algogenic organic matter (AOM), characteristic for raw waters from reservoirs, to both parameters can be assumed. In systematic laboratory experiments the influence of AOM on the BRP as well as DBP was examined. Different fractions of the AOM were chlorinated and treated with chlorine dioxide. In addition to that the influence of the ozonation was investigated. To assess the biodegradable fraction of the organic matter (BDOC) a large spectrum of byproducts (aldehydes and keto-acids) was analyzed. The BRP in the water was determined by the measurement of the increase of biomass in the water samples. It could be proved, that the chlorination of intact algae cells containing waters may cause a significant increase of the biodegradability in the water if the residual chlorine is totally required. In the case of the disinfection of the AOM containing waters with chlorine dioxide the relative increase of the BRP was lower in comparison to the chlorinated waters. The preozonation of the algae containing waters indicates an additional increase of the BRP, but only by ozonadon of the algae cells. The ozonation of the algae metabolites does not influence the BRP, but it causes a significant decrease of the THIvI-formation if chlorine is used for disinfection.     

组合工艺控制有机物及消毒副产物前体物的特性研究

通过XAD-8树脂将水中有机物分成疏水性、亲水性两部分,对传统常规处理工艺(混凝气浮、过滤)和深度处理工艺(臭氧氧化、生物活性炭)出水的DOC,UV254THMFP,HAAFP指标以及疏水、亲水有机物去除率进行了检测分析。结果表明,生物活性炭(BAC)单元工艺能同时去除疏水性和亲水性两种有机物,且两者去除率均为最高。其次去除效果较好的是传统的常规工艺。臭氧工艺具有将天然的疏水性有机物氧化成可生化降解的亲水性小分子有机物的特点,在预臭氧+常规以及O3-BAC组合工艺中,起到了强化去除有机物和消毒副产物前体物的效果。     

An overview of the integration of ozone systems in biological treatment steps.

Despite the well-known potential and performance of combined biological and ozonation processes for wastewater treatment, only few full-scale applications are published. Beside the synergistic effects of such process combination, which lead to oxidation of recalcitrant and inhibitory compounds or intermediates by enhancement of their biodegradability, the key for raising applicability is the improvement of the ozonation efficiency. An overview about the history and progress of full-scale applications, which deals with combined ozonation and biological treatment is given. Recently more than 40 applications exist, but many of them are not published. Therefore, a couple of selected not yet published applications have been mentioned in this paper. Landfill leachate and industrial wastewater treatment were mostly applicated, while treatment of municial wastewater treatment plant (WWTP) effluents are of increasing interest due to several advantages such as disinfection, decolourisation and removal of persistent dissolved organic carbon (DOC) for water re-use and groundwater recharge.     

臭氧氧化对地表水溶解性有机物去除效果的影响研究

针对臭氧氧化作用对受污染地表水中溶解性有机物去除效果的影响进行研究。结果表明:臭氧投加比低于1mgO3/mgDOC时,臭氧对UVA、CODCr和UV410等有机物去除效率较高;臭氧投加比例为0.7mgO3/mgDOC时,BOD/COD由7.4%提高至18.4%,比紫外消光度(SUVA)逐渐降低并趋于平缓;不同臭氧投加比例下水中溶解性有机物的三维荧光指纹光谱变化规律表明,受污染地表水DOM中主要荧光物质为芳香族蛋白质(荧光峰A、B和C)及类腐殖酸(荧光峰D),其中,A峰、B峰和C峰的中心位置分别位于225/300nm、225/338nm和275/342nm;臭氧投加比例为0.7mgO3/mgDOC时峰强削减率为64%～81%,同时部分芳香族蛋白质的结构也发生了变化。     

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).     

Effect of ozone on disinfection by-product formation of algae

The presence of algae in a drinking water source can have a significant impact on the treatment of that water. Algae and their extracellular organic matter can be precursors for disinfection by-product (DBP) formation which is of concern for treatment plants that employ pre-chlorination. This research examined the DBP formation of suspensions of Scenedesmus quadricauda a green alga, and the effect of ozonation on that formation. Trihalomethane formation potential (THMFP) was found to increase by 10% to 3090 when preozonation was applied versus non-ozonated samples. A slight increase in haloacedc acid (HAA) formation was also observed in the ozonated samples. Ozonation caused an increase in the dissolved organic carbon content of the algal suspension, thereby increasing the concentration of precursors. The alkalinity of the water did not significantly affect the formation potential of either THMs or HAAs.     

The occurrence of micopollutants in the aquatic environment: a new challenge for water management.

The occurrence of micropollutants in the aquatic environment has become a crucial topic in the last two decades owing to the innovative development of analytical instrumentation such as LC tandem MS. Using these new techniques it became obvious that pesticides, pharmaceuticals, ingredients of personal care products, biocides, flame retardants, and perfluorinated compounds are entering rivers and streams via treated wastewater. Also contamination of bank filtrates, groundwater and in a few cases even drinking water was identified. Wastewater treatment plants are not designed to remove polar persistent organic pollutants occurring in the sub-mg/L range and hence many of these organic pollutants are passing WWTPs to a high extent. Waterworks with a potential pesticide contamination in their raw water are equipped with advanced techniques such ozonation, activated carbon or nanofiltration enabling the removal of a high variety of other organic compounds. However, waterworks without an expected pesticide contamination are frequently equipped with common treatment processes not enabling the removal of these kinds of organic pollutants. Therefore, comprehensive management activities for protection of aquatic environments and water resources must consider the removal of all micropollutants relevant to water quality and ecology, independent of their usage or origin.