Study of the Catalytic Ozonation of Humic Substances in Water and Their Ozonation Byproducts

It is shown that using transition metals, especially Mn(II) and Ag(I), during ozonation of humic substances in water allows important reductions in the content of organic matter. Characterization of the organic compounds resulting from ozonation was made by concentrating the sample through liquid-liquid extraction or derivation with PFBOA.HCl, along with the GC/MS and GC/ECD techniques. In total, 110 different organic compounds were identified using GC/MS; mainly carboxylic acids, aromatics, hydrocarbons, aldehydes, ketones, and furan-carboxylic acids. The percentages of elimination or formation levels reached during ozonation are discussed.     

Ozone Cooling Tower Treatment With and Without Mineral Removal

This paper builds on a prior paper by this author, McGrane (1991). In that paper, ozone is used as the sole means of cooling tower water treatment. The paper discusses water conservation by increased cycles of concentration, greatly increased efficiency through extremely low biological populations, and corrosion data which is compared to ozonated and chemically treated towers.

New in this paper are the results from the combination of a low pressure reverse osmosis system with ozone treatment for cooling tower water. Scale formation has continued to plague cooling towers with high concentrations of calcium in the make-up water. The use of a mineral removal system in cases of extremely hard water has made ozone an attractive alternative to traditional chemicals in many areas.     

Homogeneous Catalyzed Ozone Decomposition in the Presence of Co(II).

The homogeneous decomposition of ozone in the presence of a Co(II) catalyst has been investigated in aqueous solution. Under the conditions investigated (Co(II) concentration: 0.0 – 2.0?ppm, pH: 1.6- 8.4, O₃ concentration: 5 10^?5 – 2.0 10⁴?M) the process can be assumed to follow pseudo first order kinetics with respect to ozone. Cobalt concentration dependency also obeys first order kinetics although it may be considered to reach a steady state concentration. pH exerts a positive influence on the decomposition rate from 1.6 to 7.1, the process leveling off at pH 8.4. An Arrhenius analysis of the temperature effect gave a moderate activation energy of the global reaction (E=10917?cal mol^?1). A more detailed radical mechanism than a simple pseudo first order reaction can be postulated for simulation purposes. By numerical optimization of some unknown kinetic constants the influence of several operating variables can be adequately predicted.     

The Oxidation of Manganese and Disinfection By Ozonation in Water Purification Processing

The surface water of a river has been used as the raw water by the Waterworks Bureau of Osaka City. At present, the manganese contained in the raw water is oxidized by breakpoint chlorination and all oxides are removed by coagulation, sedimentation followed by rapid sand filtration, with chlorine being used as the final disinfectant.

Prechlorination was not conducted in the ongoing pilotplant experiment of an advanced water purification process with ozone and granular activated carbon. It is necessary, therefore, to oxidize manganese by the oxidative effect of ozone instead of prechlorination.

It is important for the treatment of manganese to adjust the ozone dosage because manganese is oxidized up to the soluble septavalent state by the surplus ozone. Since ozone does not continue to exist for very long in water, though its disinfecting power is high, final disinfection by chlorine is required.     

给水处理投药控制的非线性数学模型及仿真

为了更好地控制给水处理系统中的投药量,本文用机理建模及分布参数系统建模的方法,建立了可用于给水处理投药过程控制的数学仿真模型,该仿真模型包括了给水处理过程中混凝、絮凝、沉淀3步最基本过程,反映了水厂各设计参数对水处理投药控制效果的影响以及混凝药剂与絮凝池、沉淀池出水浊度之间的动态响应关系.仿真模拟了水厂原水浊度发生突变对絮凝池及沉淀池的出水浊度的动态影响,仿真结果与实际水厂数据相近.研究结果可以用来进一步研究水处理过程控制,为更深入研究适用于给水处理的非线性控制方法提供良好的模拟仿真分析平台.     

泡沫塑料表面的磁控溅射镀膜技术研究

对硬质聚氨酯泡沫塑料进行适当的前处理(涂刮不饱和聚酯腻子和喷涂双组份聚氨酯清漆),再采用磁控溅射镀膜技术对其进行紫铜T2镀膜,能够有效地降低泡沫塑料的吸水率,提高尺寸稳定性.     

南水北调中线工程水价形成机制初探

回顾了南水北调中线工程水价形成过程,指出了现行水价方案存在的问题。对真实水价形成机制进行了论述,认为制定水价应遵循公平负担、成本回收、合理利润、价格调整和水资源配置原则;同一水质、同类用户、不同水源的用水,应执行统一的水价;不同行业实行不同水价。鼓励受水区各省市间开展水量配额交易,最大限度发挥工程效益。供水水价既要反映水资源的稀缺程度和水环境治理成本,促进资源的节约使用和环境保护,提高全民节水意识,又要保证供水管理单位能够正常持续经营,具备自我积累、自我发展的能力。     

Performance comparison of reduced models for leak detection in water distribution networks

This paper presents a methodology for comparing the performance of model-reduction strategies to be used with a diagnostic methodology for leak detection in water distribution networks. The goal is to find reduction strategies that are suitable for error-domain model falsification, a model based data interpretation methodology. Twelve reduction strategies are derived from five strategy categories. Categories differ according to the manner in which nodes are selected for deletion. A node is selected for deletion according to: (1) the diameter of the pipes; (2) the number of pipes linked to a node; (3) the angle of the pipes in the case of two-pipe nodes; (4) the distribution of the water demand; and, (5) a pair-wise combination of some categories.The methodology is illustrated using part of a real network. Performance is evaluated first by judging the equivalency of the reduced network with the initial network (before the application of any reduction procedure) and secondly, by assessing the compatibility with the diagnostic methodology. The results show that for each reduction strategy the equivalency of networks is verified. Computational time can be reduced to less than 20% of the non-reduced network in the best case. Results of diagnostic performance show that the performance decreases when using reduced networks. The reduction strategy with the best diagnostic performance is that based on the angle of two-pipe nodes, with an angle threshold of 165°. In addition, the sensitivity of the performance of the reduced networks to variation in leak intensity is evaluated. Results show that the reduction strategies where the number of nodes is significantly reduced are the most sensitive.Finally this paper describes a Pareto analysis that is used to select the reduction strategy that is a good compromise between reduction of computational time and performance of the diagnosis. In this context, the extension strategy is the most attractive.     

南水北调南干渠工程穿越风险地段的施工方法

南水北调南干渠Ⅲ标需要全段穿越大兴灌渠、桥墩、垃圾坑以及二元地质结构地层等风险地段,施工难度大.施工中采取了铺设土工膜、现浇混凝土方涵导流、加密钢格栅等方法,安全地穿越了风险地段.     

宜春市状元洲抬水工程设计浅析

以江西省宜春市状元洲抬水工程为实例,探讨了橡胶坝及升卧式闸门在抬水工程中的设计及应用.