超声/臭氧氧化处理含酚废水实验研究

在实验装置上对超声/臭氧联合处理含酚废水进行了实验研究。考察了废水初始pH值、反应时间、臭氧通入量、超声功率等因素对酚去除率的影响。研究表明,超声辐射在臭氧氧化过程中起加速反应的作用,而且随着超声功率的增大,加速反应的能力增强;废水初始pH值为11时酚去除效果最佳;随着臭氧通入量的增大、反应时间的延长,酚去除率不断增大;超声/臭氧处理酚废水过程中酚的降解规律符合表观一级反应。     

臭氧高级氧化法处理染料废水的研究

采用臭氧高级氧化技术对某染料废水进行处理,探究不同条件对染料废水COD以及色度的去除效果的影响,确定最佳工艺条件。在最佳条件下,采用单独臭氧、单独紫外、臭氧-紫外、臭氧-双氧水以及臭氧-铁炭五种氧化方法对染料废水进行处理。结果表明:臭氧氧化技术最佳条件为pH值=8,臭氧流量80 L/h,反应时间为2 h;采用最佳处理方案,采用臭氧-紫外高级氧化技术处理染料废水,其脱色率为98.3%,COD去除率为67.0%。     

超声-双氧水和亚铁离子体系处理含酚废水研究

在实验装置上对超声-双氧水和亚铁离子体系联合处理含酚废水进行了实验研究。主要考察了废水初始pH值、初始双氧水浓度、超声功率、反应时间等因素对酚去除率的影响。实验结果表明：超声辐射可以在双氧水和亚铁离子体系氧化过程中起加速反应的作用，而且随着超声功率的增大，加速反应的能力增强；实验条件下废水初始pH值为4～6．8，初始双氧水浓度为140mg／L时酚去除效果最佳；超声-双氧水和亚铁离子体系处理含酚废水过程中苯酚的降解规律符合表现一级反应。     

纳米二氧化钛光催化氧化降解苯酚废水实验

开展实验室模拟苯酚废水的二氧化钛光催化氧化实验。结果表明：在苯酚废水曝气量为0～3L/min的条件下，随着曝气量的增大，COD去除率先增大后减小；初始浓度不变，光照时间为1h的条件下， 调节pH值在3～11，苯酚废水COD去除率随着pH值的增大而减小，当pH值为11时， COD去除率又开始增 大，酸性条件比碱性条件下COD去除率高；随着二氧化钛投加量的增加，COD去除率增大，当二氧化钛投加量 为10g/L时，COD去除率反而降低，二氧化钛最佳投加量为3g/L；随着苯酚废水初始浓度由75mg/L增加至300mg/L，COD去除率由78.2％降低到58.1％；反应温度的改变对COD和TOC的去除率没有影响。     

催化氧化法在钻井废水处理中的应用

在油气田深井钻探过程中产生的钻井液,经固-液分离处理后产生的废水具有化学需氧量高、色度高、矿化度高、含油量高等特点,须进一步进行处理。采用Fenton试剂对钻井废水进行了催化氧化处理实验。结果表明,处理后, 废水中化学需氧量(COD)去除率可达82%,色度去除率为98.5%。H2O2/Fe2+投量摩尔比、H2O2/初始COD摩尔比、pH值和反应时间对废水COD、色度的去除率均有较大影响。用Fenton试剂催化氧化工艺处理聚磺体系钻井废水还具有处理效率高、操作简便、适用范围广等优点。     

超声内电解处理高浓度含盐有机废水的实验研究

分别研究了铁碳内电解、超声波辐照以及不同组合方式对高盐度泡菜废水的处理,重点研究了铁碳比、铁碳加入量、溶液pH值、处理时间、超声功率密度等因素对高含盐量泡菜废水降解率的影响。实验表明,铁碳加入对内电解处理效果影响显著,超声波处理该废水的最佳pH值为7;超声内电解处理的最佳条件为：铁碳比2∶1,铁碳加入体积为溶液体积的25%,溶液初始pH值为7,超声功率密度为0.225w/cm3,曝气处理90min。处理后出水COD去除率大于50%,达到了对该类高浓度含盐废水的预处理效果,降低了后续生化系统的处理负荷。     

利用湿式氧化法处理油气田压裂废液

以间歇型水热反应装置为反应器处理油气田压裂废液.通过正交实验分析各相关因素对压裂废液COD去除率的影响程度。结果表明:湿式氧化法处理油气田压裂废液可迅速加快反应速度.明显提高处理效率;各相关因素对压裂废液COD去除效率的影响由大到小依次为:反应时间>氧化剂>反应温度;在反应温度237℃,反应时间30 min.氧化荆添加量0.30 mL的条件下,COD的去除率达到94.0%。湿式氧化法可应用于油气田排出的高浓度压裂废液的处理。     

H2O2／Fe^2＋氧化偶合混凝法处理干膜废水的研究

本文研究了H2O2／Fe^2＋氧化偶合混凝法处理印刷电路板厂干膜废水。讨论了包括过氧化氢浓度、亚铁离子浓度、pH值、时间和混凝pH值等影响因素,试验结果表明,当过氧化氢浓度为457.0mg/L、铁离子浓度为400mg/L、氧化pH值4.0、反温度为40℃、反应时间180min时,COD去除率达84.7%,出水的水质达到排放标准。     

Fenton氧化工艺处理DNT废水研究

DNT废水因其成分复杂、毒性大、难降解、对环境污染严重等特点,成为废水处理中的一个难题。本试验研究了难以生物降解DNT生产废水Fenton氧化处理效果,考查了各影响因子最佳工艺条件。结果表明,在pH值为2;FeSO4.7H2O投加量为200mg/L;H2O2投加量为2mL/L;反应时间为1h的条件下,Fenton氧化工艺COD去除率为47.76%,DNT去除率为87.37%左右。     

钡盐沉淀法处理纳米银工业废水

液相化学还原法制备纳米银是近些年的研究热点之一,但工艺过程产生的工业废水处理问题未有关注。首次采用钡盐沉淀法处理纳米银工业废水,考察了反应温度、p H值、钡盐种类等因素对废水COD (化学需氧量)及色度去除率的影响。其最佳工艺条件如下:反应温度15℃,初始p H值10. 5,反应时间1h,每100mL废水投加二水氯化钡8g;废水COD去除率为85. 6%,色度去除率高达97. 1%。傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)等表明:纳米银工业废水中存在醌-氢醌类化合物,此羟基醌类化合物可与溶液中的钡离子反应生成沉淀而得以去除;另外,新生成的硫酸钡细微颗粒带正电,絮凝沉降过程对废水中的羟基醌类化合物存在吸附作用。     

Provincial development plans in Zimbabwe: an analysis of their content,structure and methodology

Zimbabwean provincial plans were instituted to help in the achievement of the national goal of the creation of an egalitarian, socialist and integrated society. The national goal itself was adopted as an antithesis to the dualist society characterised by spatial, economic, social, politican and technological inequalities that Zimbabwe inherited from colonialism. This meant that provincial plans had to play both a functional (or growth allocating/distribution) and a territorial (or redistribution) role.

This paper reviews their role in achieving the national goal by examining their functions, content, structure and methodology. The paper concludes that because of their nature, provincial plans are not suitable tools for the achievement of the national goal.     

National minerals policies and stakeholder participation for broad-based development in the southern African development community (SADC)

This paper explains how the well-accepted concept of improved stakeholder participation during mineral policy development leads to a national mineral policy that accommodates the diverging views and interests that allows wide acceptance of decisions, enhancing the success of implementation and, ultimately, national benefits. This process is based on lessons learnt during the South African experience and has been successfully applied in the development of the Namibian and Malawian national minerals policies. An effective policy in the SADC will engineer the delicate balance between poverty reduction and an internationally competitive minerals sector. This balance enhances the possibility of long-term economic growth and development in the SADC region. The overriding advantage of this strategy is that it generates ‘home-grown’ policy instruments and implementation of mineral law with which stakeholders can identify. This process presents a new challenge to traditional policy formulation strategies in emerging economies and the bottom-up approach, linked to wide political support, allows the potential realisation of national objectives.     

A DISTRIBUTED DYNAMIC WATERSHED MODEL1

ABSTRACT: A distributed watershed model was developed to mathematically simulate overland and channel flow for a single-event storm. The modeled watersheds in the study were subdivided into rectangular grid elements. All hydrologically significant parameters, such as land slope, rainfall and precipitation excess, were assumed to be uniform within each element. The Green-Ampt method was adopted to generate precipitation excess for each element during the simulation period. A two-dimensional diffusion wave model was used for overland flow routing and an iterative Alternative Direction Implicit scheme was used to solve the simultaneous overland flow equations. Once the overland flow became inflow to the channel, a one-dimensional dynamic wave flood routing technique, based on a four-point, implicit, non-linear finite difference solution of the St. Venant equation of unsteady flow, was applied. A limited number of comparisons were made between simulated and observed hydrographs for areas of about one square mile. Given the appropriate parameters, the model was able to accurately simulate runoff for single-event storms. This paper describes a distributed watershed model developed to simulate overland and channel flow. Comparisons were made between simulated and observed hydrographs for three watersheds. The model was able to accurately simulate the runoff for single-event storms using 61-m by 61-m (200 ft by 200 ft) watershed grid elements.     

INTEGRATED WATER RESOURCES MANAGEMENT WHO SHOULD LEAD,WHO SHOULD PAY?1

ABSTRACT: Improving water management to meet future global needs will certainly require technical advances, but the main challenge is to integrate the viewpoints of diverse societal interests into decisions about allocation of water resources. The integration cannot be done solely by the market because it requires a balancing among interests which do not respond well to market forces, nor by the state alone because of institutional problems. The concept of “integrated water resources management” has been developed to provide the framework for the required balancing of interests, and, like similar concepts in industries other than water, it has a dual purpose - to link stakeholders and apply best practices to management actions. To clarify the process of integrated water management, the paper focuses on two questions: who should lead integrated water resources management and who should pay for it? Several examples are given to illustrate a range of situations. The paper concludes with a call to improve paradigms of integrated water management, a proposition that water organizations should accept and budget for their external responsibilities as well as their direct missions, affirmation of the need for state and federal agencies to be involved with local interests, a call for better scientific and public information, and identification of the need for continued work to improve the process of integrated water management.     

Green Symbolism in the Genetic Modification Debate

The character of the current controversy over geneticallymodified (GM) agriculture, typified by protesters' use of emotivesymbolism, has been largely inspired by the Green movement'snon-governmental organizations and political parties. This articleexplores the deeper philosophical and spiritual motivations of the Greenmovement, to inquire why it is implacably opposed to GM agriculture. TheGreen movement's anti-capitalism, exemplified by the hate-symbol statusof Monsanto as the company pioneering GM crops, is viewed within thewider context of alienation in the modern era. A complex of meanings isseen in Frankenstein as the focal symbol of GM protests, includingperceptions of risk, fears of the remixing of living identities seen ingenetic engineering, and resentment at the spiritual nihilism of thereduction of life to the digital code of DNA. By contrast, RobertGoodin's Green Theory of Value, which postulates the deep psychologicalimportance of nature in locating the self in a meaningful context largerthan ourselves, can explain the power of the Green symbol of thethreatened environment, Gaia. The advent of GM agriculture seems toimply that capitalism and technology can now enframe nature itself,leaving a world devoid of natural myth or meaning, with no escape fromthe alienation and nihilism of modernity. The central question posed forprotagonists of the GM debate is whether their agenda is based on thesepowerful but mythical conceptions of the environment, or whetherpreservation of the real environment is their primary ethic.     

STATE VARIABLE MODEL FOR URBAN RAINFALL-RUNOFF PROCESS1

ABSTRACT: A nonlinear hydrologic system model has been developed for analyzing the urban rainfall-runoff process. The model is formulated as a state variable model consisting of several parameters. A search technique is employed to find the set of parameters for which the model's response best fits observed data. The model could be used in either a simulation or forecasting mode. The model is applied to observed data for the Waller Creek Watershed in Austin, Texas, to develop the model parameters for various levels of urbanization of the watershed. The trend of each parameter with respect to levels of urbanization is examined.     

Formulation of resource depletion index

A resource depletion index can serve as a quantitative tool to evaluate the level of depletion for natural resources. This study introduces two types of resource depletion indices, the global resource depletion index and the local resource depletion index. Global resource depletion index mainly concerns global reserves and the annual consumption rate of these resources. The local resource depletion index not only considers global reserves and their annual consumption rate, but also considers the local factors such as local reserves, local recycling rates, and local resource import characteristics. This study considers the local resource characteristics of Taiwan and develops calculations for local resource depletion indexes for the resources of cobalt, molybdenum, tungsten, copper, aluminum, lead and zinc.     

Preliminary studies about effects of ELF and TAMMEF electromagnetic fields on human lymphomonocytes

In our paper we studied the effects of exposure to ELF (extremely low frequency) or musically generated TAMMEF (therapeutic application of musically modulated electromagnetic fields) electromagnetic fields on the tumor necrosis factor alpha (TNF-α) release induced by a lipopolysaccharide (LPS) from cultured human lymphomonocytes of peripheral blood. Lymphomonocytes, isolated from blood donors buffy-coat, were prepared using standard techniques in cell culture flasks, kept in CO₂ incubator, with controlled temperature and humidity for 5 days. Flasks were subjected to an ELF electromagnetic field (100 Hz sinusoidal) or to TAMMEF electromagnetic fields (with intensity, frequency, and wave shape randomly modified in time, so that all possible codes can occur during a single application). The TNF-α release was determined by ELISA test every 24 h for 92 h and the results were evaluated by a non-parametric test. LPS induces a stronger TNF-α release in cultures that were subjected to ELF when compared with cultures subjected to TAMMEF, at each time period of the experimental protocol. These results seem to indicate that TAMMEF is able to induce a complex modulation of LPS-induced TNF-α release, a cytokine with pro inflammatory property whose release during chronic or neoplastic inflammatory diseases has strong negative effects on several organ systems.     

Cadmium—Towards a rational use of a toxic element

Because of its toxicity, cadmium creates an environmental problem as well as a health hazard for exposed workers. Most cadmium emissions arise from the intentional use of the element. It is therefore mandatory to reduce cadmium consumption to the lowest possible level. Cadmium pigments, mainly used in plastic processing, can be replaced in all applications where the processing temperature does not exceed 300°C. Newly developed polyvinyl chloride stabilizers promise to be an excellent substitute for cadmium stabilizers in even the most demanding applications. Cadmium plating, still extensively used in the United States and the West Germany, has been virtually abandoned in Japan. Improved lead acid batteries are replacing vented nickel cadmium batteries because of their cost effectiveness. While in these applications cadmium use is declining, more and more cadmium is needed for the manufacturing of sealed nickel cadmium batteries. These relatively small electrochemical cells are used mainly by individual consumers. Here cadmium can only be replaced in some marginal applications. The high cadmium content of these batteries (up to 22%) makes them a good candidate for recycling of the heavy metal.     

LONG-TERM EQUILIBRIUM PHOSPHORUS CONCENTRATIONS IN THE EVERGLADES AS PREDICTED BY A VOLLENWEIDER-TYPE MODEL1

ABSTRACT: Anthropogenic phosphorus loading, mainly from the Everglades Agricultural Area (EAA), is believed to be the primary cause of eutrophication in the Everglades. The state of Florida has adopted a plan for addressing Everglades eutrophication problems by reducing anthropogenic phosphorus loads through the implementation of Best Management Practices (BMPs) in agricultural watersheds and the construction of stormwater treatment areas (STAs). Optimizing the effectiveness of these STAs for reducing phosphorus concentrations from agricultural runoff is a critical component of the District's comprehensive Everglades protection effort. Therefore, the objective of this study was to develop a simple tool that can be used to estimate STAs’performance and evaluate management alternatives considered in the Everglades restoration efforts. The model was tested at two south Florida wetland sites and then was used to simulate several management alternatives and predict ecosystem responses to reduced external phosphorus (P) loadings. Good agreement between model predictions at the two wetland sites and actual observations indicated that the model can be used as a management tool to predict wetlands’response to reductions in external phosphorus load and long-term P levels in aquatic ecosystems. Model results showed that lowering P content of the Everglades Protection Area (EPA) depends on reducing P loads originating from EAA discharges, not from rainfall. Assuming no action is taken (e.g., no BMPs or STAs implemented), the steady state model predicted that the average concentration within the modeled area of the marsh would reach 20 μg L^?1 within five years. With an 85 percent reduction in P loading, the steady-state model predicted that Water Conservation Area 2A (WCA-2A) P concentration will equilibrate at approximately 10 μ L^?1, while elimination of all loadings is projected to further reduce marsh P to values less than 10 μg L^?1.