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.     

臭氧催化氧化技术在饮用水处理中的应用

臭氧催化氧化技术是一种新兴的饮用水处理技术,其反应过程利用羟基自由基(·OH)的强氧化性,降解处理化学结构复杂、难以被生物降解的有机污染物。针对该技术的作用机理、反应类型及应用前景等展开论述,并且对臭氧催化氧化技术所存在的问题进行了分析。     

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.     

饮用水臭氧应用安全性研究

对预臭氧、臭氧—生物活性炭等技术与常规水处理工艺联用中有机物去除效果、消毒副产物THMFP的消除等进行了研究。结果表明:采用适量臭氧(如1mg/L)预氧化,可有效提高混凝过程中有机物去除率;THMFP从常规处理的116μg/L降至78μg/L(1mg/LO3)。与预臭氧强化混凝联用的臭氧—生物活性炭工艺能进一步降低DOC和THMFP。研究发现:溴酸盐随着臭氧含量呈现起伏变化,溴酸盐相关前驱物不易分离去除。两次臭氧投加(预臭氧和主臭氧)均导致溴酸盐、AOC和甲醛升高;其含量可分别在后续的混凝过滤及生物活性炭过程中得到控制,仅AOC含量较原水和常规工艺出水有所升高。     

用于饮用水再矿化工艺的石灰石选择

珠江中下游的地表水具有低碱低硬的特点,为了改善饮用水水质化学稳定性,提出了石灰石接触池工艺,该工艺具有维护简单、管理方便、运行安全和成本低廉等优点。石灰石接触池工艺中,石灰石的选择是很关键的一部分,直接影响到石灰石接触池的处理效果。试验结果表明,影响石灰石溶解特性的主要因子有石灰石中碳酸钙含量、不溶杂质以及单位体积空隙的表面积。当碳酸钙含量高于98%时,溶解效果非常理想。不溶杂质容易在石灰石表面生成残渣层,降低传质速率。单位体积空隙的石灰石表面积和石灰石的粒径、球度、孔隙率有关。     

饮用水处理工艺出水对雄性生殖系统的生物活性

饮用水水源中内分泌干扰物(EDCs)的存在引起人们的广泛关注。以大鼠睾丸支持细胞为对象,研究了饮用水常规处理工艺各处理单元出水对于雄性生殖系统的生物活性。结果表明,原水受到一定程度的污染,可以诱导睾丸支持细胞的增殖。各工艺单元出水对睾丸支持细胞均没有增殖作用,说明常规水处理工艺有效地降低了原水中EDCs的生物活性。原水诱导睾丸支持细胞增殖的作用机制主要是通过改变细胞周期中的S期和G2期,使其明显升高。水样对波形蛋白的表达具有抑制作用,尤其是龙头水,表明管网输送过程中可能引入了新的物质,细胞周期分析也显示管网运输过程对于出水生物活性的改变与水厂内处理环节不同。     

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。     

Pilot experiments with electrodialysis and ozonation for the production of a fertiliser from urine.

Pilot tests were performed with a process combination of electrodialysis and ozonation for the removal of micropollutants and the concentration of nutrients in urine. In continuous and batch experiments, maximum concentration factors up to 3.5 and 4.1 were obtained, respectively. The desalination capacity did not decrease significantly during continuous operation periods of several weeks. Membrane cleaning after 195 days resulted in approximately 35% increase in desalination rate. The Yeast Estrogen Screen (YES), a bioassay that selectively detects oestrogenic compounds, confirmed that about 90% of the oestrogenic activity was removed by electrodialysis. HPLC analysis showed that ibuprofen was removed to a high extent, while other micropollutants were below the detection limit. In view of the fact that ibuprofen is among the most rapidly transported micropollutants in electrodialysis processes, this result indicates that electrodialysis provides an effective barrier for micropollutants. Standardised plant growth tests were performed in the field with the salt solution resulting from the treatment by electrodialysis and subsequent ozonation. The results show that the plant height is comparable to synthetic fertilisers, but the crop yield is slightly lower. The latter is probably caused by volatilisation losses during field application, which can be prevented by improved application technologies.     

Climate change and drinking water production in The Netherlands: a flexible approach.

Climate change increases water system dynamics through temperature changes, changes in precipitation patterns, evaporation, water quality and water storage in ice packs. Water system dependent economical stakeholders, such as drinking water companies in The Netherlands, have to cope with consequences of climate change, e.g. floods and water shortages in river systems, upconing brackish ground water, salt water intrusion, increasing peak demands and microbiological activity. In the past decades, however, both water systems and drinking water production have become more and more inflexible; water systems have been heavily regulated and the drinking water supply has grown into an inflexible, but cheap and reliable, system. Flexibility and adaptivity are solutions to overcome climate change related consequences. Flexible adaptive strategies for drinking water production comprise new sources for drinking water production, application of storage concepts in the short term, and a redesign of large centralised systems, including flexible treatment plants, in the long term. Transition to flexible concepts will take decades because investment depreciation periods of assets are long. This implies that long-term strategies within an indicated time path have to be developed. These strategies must be based on thorough knowledge of current assets to seize opportunities for change.     

微污染水源水预处理技术进展

阐述了水源水预处理的必要性，介绍了各种微污染水源水的预处理技术，并针对各种处理工艺的优点及存在的问题进行了讨论，并提出解决办法。     

绿色工艺——第三代饮用水净化工艺的发展方向

绿色工艺就是要求对水的天然属性没有影响或影响削减到最小,是第三代饮用水净化工艺发展和变革的重要方向.第一代和第二代饮用水净化工艺中因需向水中投加多种化学药剂,会影响水的固有化学成分、含量及其存在形态,一般认为是非绿色工艺;而物理方法、物理化学方法、生物方法等对水的天然属性影响很小甚至没有影响,一般认为是绿色工艺.膜技术...     

When climate change is a fact! Adaptive strategies for drinking water production in a changing natural environment.

Climate change increases water system dynamics through temperature changes, changes in precipitation patterns, evaporation, and water quality and water storage in ice packs. Water system dependent economical stakeholders, such as drinking water companies in the Netherlands, have to cope with consequences of climate change, e.g. floods and water shortages in river systems, upcoming of brackish ground water, salt water intrusion, increasing peak demands and microbiological activity due to temperature rise. In the past decades, however, both water systems and drinking water production have become more and more inflexible; water systems have been heavily regulated aiming at maximum security and economic functions and the drinking water supply in the Netherlands has grown into an inflexible, but cheap and reliable, system. At a water catchment scale, flexibility and adaptation are solutions to overcome climate change related consequences. Flexible adaptive strategies for drinking water production comprise new sources for drinking water production, application of storage concepts in the short term, and a redesign of large centralized systems, including flexible treatment plants, in the long term. Transition to flexible concepts will take decades because investment depreciation periods of assets are long. These strategies must be based on thorough knowledge of current assets to seize opportunities for change.     

Development of an integrated membrane process for water reclamation.

An integrated membrane process (IMP) comprising a membrane bioreactor (MBR) and a reverse osmosis (RO) process was developed for water reclamation. Wastewater was treated by an MBR operated at a sludge retention time (SRT) of 20 days and a hydraulic retention time (HRT) of 5.5 h. The IMP had an overall recovery efficiency of 80%. A unique feature of the IMP was the recycling of a fraction of RO concentrate back to the MBR. Experimental results revealed that a portion of the slow- and hard-to-degrade organic constituents in the recycle stream could be degraded by an acclimated biomass leading to an improved MBR treatment efficiency. Although recycling concentrated constituents could impose an inhibitory effect on the biomass and suppress their respiratory activities, results obtained suggested that operating MBR (in the novel IMP) at an F/M ratio below 0.03 g TOC/g VSS.day could yield an effluent quality comparable to that achievable without concentrate recycling. It is noted in this study that the novel IMP could achieve an average overall TOC removal efficiency of 88.940% and it consistently produced product water usable for high value reuse applications.     

Biofilm in water pipelines; a potential source for off-flavours in the drinking water.

Volatile organic compounds (VOC) are identified in natural biofilm established in plastic pipes used at the drinking water supply. Odour potent VOCs such as ectocarpene, dictyopterene A and C', geosmin, beta-ionone, 6-methyl-5-hepten-2-one, menthol and menthone were prominent compounds in biofilm in the distribution network and at raw water test sites, and are associated with algae and cyanobacteria present in the raw water source.     

新《生活饮用水卫生标准》揭示了饮用水安全消毒的必要性

围绕我国《生活饮用水卫生标准》(GB5749—2006)中对微生物、毒理、消毒剂指标等的更高要求,分析了传统消毒方式存在的问题,提出了安全消毒的概念,指出紫外线 氯组合消毒工艺是保障消毒安全的重要技术选择。为保障饮用水安全,降低微生物安全风险,减少消毒副产物形成,紫外线 氯组合消毒将成为实施饮用水安全消毒的重要技术选择。     

颗粒计数仪器在给水处理工艺中的应用探索

采用在线颗粒计数仪和在线浊度仪并行监测长江水源水常规处理单元出水水质,对常规处理工艺运行参数进行优化研究.结果表明,采用常规工艺处理长江原水,在运行周期内,滤池出水中2～3 μm颗粒物数平均在50粒/mL以下,滤后水中浊度呈逐级下降趋势,颗粒物总量则逐渐上升,两者之间不存在比例关系;确定以滤池后出水中2～3 μm颗粒物数急剧波动作为滤池是否需要反冲洗的判断依据,并初步验证当原水平均水温在18℃以上时,普通快滤池运行周期可以延长至42 h,滤池过滤效率平均在3以上.     

IBAC—GAC工艺用于饮用水深度处理的研究

利用固定化生物活性炭—颗粒活性炭(IBAC—GAC)技术对以湘江(长沙段)为原水的给水厂常规处理出水进行深度处理。试验结果表明,IBAC—GAC工艺对氨氮的去除率稳定在91%以上,最高达到98.64%,有机物去除率较高,CODMn去除率基本稳定在40%左右,其对汞、镉等重金属离子也具有良好的吸附作用,出水浊度低,可保持在0.8NTU以下,出水细菌总数符合生活饮用水卫生标准。     

Investigation of factors affecting rural drinking water consumption using intelligent hybrid models

Identifying the factors affecting drinking water consumption is essential to the rational management of water resources and effective environment protection. In this study, the effects of the factors on rural drinking water demand were studied using the adaptive neuro-fuzzy inference system (ANFIS) and hybrid models, such as the ANFIS-genetic algorithm (GA), ANFIS-particle swarm optimization (PSO), and support vector machine (SVM)-simulated annealing (SA). The rural areas of Hamadan Province in Iran were selected for the case study. Five drinking water consumption factors were selected for the assessment according to the literature, data availability, and the characteristics of the study area (such as precipitation, relative humidity, temperature, the number of subscribers, and water price). The results showed that the standard errors of ANFIS, ANFIS-GA, ANFIS-PSO, and SVM-SA were 0.669, 0.619, 0.705, and 0.578, respectively. Therefore, the hybrid model SVM-SA outperformed other models. The sensitivity analysis showed that of the parameters affecting drinking water consumption, the number of subscribers significantly affected the water consumption rate, while the average temperature was the least significant factor. Water price was a factor that could be easily controlled, but it was always one of the least effective parameters due to the low water fee.     

Investigation of microbial communities on reverse osmosis membranes used for process water production.

In the present study, the diversity and the phylogenetic affiliation of bacteria in a biofouling layer on reverse osmosis (RO) membranes were determined. Fresh surface water was used as a feed in a membrane-based water purification process. Total DNA was extracted from attached cells from feed spacer, RO membrane and product spacer. Universal primers were used to amplify the bacterial 16S rRNA genes. The biofilm community was analysed by 16S rRNA-gene-targeted denaturing gradient gel electrophoresis (DGGE) and the phylogenetic affiliation was determined by sequence analyses of individual 16S rDNA clones. Using this approach, we found that five distinct bacterial genotypes (Sphingomonas, Beta proteobacterium, Flavobacterium, Nitrosomonas and Sphingobacterium) were dominant genera on surfaces of fouled RO membranes. Moreover, the finding that all five "key players" could be recovered from the cartridge filters of this RO system, which cartridge filters are positioned before the RO membrane, together with literature information where these bacteria are normally encountered, suggests that these microorganisms originate from the feed water rather than from the RO system itself, and represent the fresh water bacteria present in the feed water, despite the fact that the feed water passes an ultrafiltration (UF) membrane (pore size approximately 40 nm), which is able to remove microorganisms to a large extent.     

Catalyzed ozonation process with GAC and metal doped-GAC for removing organic pollutants.

The purpose of this study was to investigate the catalytic role of granular activated carbon (GAC), and metal (Mn or Fe) doped-GAC, on the transformation of ozone into more reactive secondary radicals, such as hydroxyl radicals (*OH), for the treatment of wastewater. The GAC doped with Mn showed the highest catalytic performance in terms of ozone decomposition into OH radicals. Likewise, activated carbon alone accelerated the ozone decomposition, resulting in the formation of *OH radicals. In the presence of promoters, the ozone depletion rate was enhanced further by the Mn-GAC catalyst system, even under aqueous acidic pH conditions.