THE ECONOMIC FEASIBILITY OF DUAL PURPOSE NUCLEAR DESALINATION OF GROUND WATER1

ABSTRACT: The economic feasibility of a large scale dual purpose (desalting water and power production) facility were evaluated. Although a site in the Tularosa basin of southern New Mexico was chosen as a case study for this analysis, it is believed that the approach and consequential results would be applicable to alternative sites in the Southwest. The basic project evaluated included: a) a ground water well field; b) a dual purpose, nuclear, desalination plant; c) a mineral recovery plant; and d) a reservoir for recreation and irrigation storage. Principle project outputs included electrical power, minerals, recreation, and water for either irrigated agricultural production or export to an adjoining river basin. Two alternative project designs were developed for detailed analysis. The first alternative encompassed all major project components. The results, in discounted net values used to assess the feasibility of the project, were essentially negative; that is, values were less than zero for full scale development. The net benefits ranged from $-986.57 million at a 5 percent discount rate, to $-1,137.528 million at a discount rate of 10 percent. In the second alternative, exportation of the desalted water from the Tularosa basin to two adjacent rivers was analyzed with somewhat better net benefits, ranging from $-382,527 million to $-478,612 million at the 5 and 10 percent discount rates.     

重金属污染土壤淋洗优化技术进展

综述了重金属污染土壤常规淋洗的优化技术,包括复合减量化技术、淋洗助剂的使用等化学优化技术以及电动力法、超声和微波法等物理优化技术;同时介绍了新型绿色淋洗剂的研发和使用情况,包括可降解螯合剂、植物浸提液及生物表面活性剂;概述了淋洗液的后处理和回用工艺。提出了开发新型淋洗剂、淋洗优化技术及淋洗液后处理技术的建议。     

VELOCITY CONTROL AS A TOOL FOR OPTIMAL PLUME CONTAINMENT IN THE EQUUS BEDS AQUIFER,KANSAS1

ABSTRACT: A ground-water-management model was developed to investigate the best management options for the containment of an oil-field-brine plume in the Equus Beds aquifer in south-central Kansas. The main purpose of the management model was to find the optimal locations and minimum rates of pumpage of a set of plume-interception wells, to successfully reverse the velocity vectors at observation wells located along the plume front, and also to satisfy freshwater demands from supply wells. The effects of the calculated minimum withdrawals from the interception wells on the migration of contaminants throughout the ground-water system were evaluated utilizing a solute-transport model. This latter analysis was carried out to ensure the containment of the plume. Whereas application of the management model to the study area achieves the management objectives, the implementation of the results is believed to be impractical and expensive. This is because a considerable amount of water must be pumped out to reverse the velocity vectors in the vicinity of the plume. In general, the proposed technique of pollutant containment may be effective when applied to aquifers having low hydraulic gradients and/or to aquifers with hazardous plumes whose containment is not subject to economic constraints.     

Deposition of Inorganic Particulate Aerosols to Vegetation - A New Method of Estimating

A new, direct method was developed for quantifying inorganic particulate aerosols trapped by the forest canopy, and for determining the resulting input of elements to a forest ecosystem. The method is based on direct measurements of only six parameters. Using this method, it is possible to determine the load of aerosols trapped by the forest canopy and deposited to leaves, as well as the load of aerosols falling to the forest floor by impaction on plants. It is also possible to estimate the aerosol input of soluble and insoluble elements to an ecosystem. With this new method it has been found that the load of aerosols trapped by the canopy of a mixed forest located in the Rybnik Coal Basin averaged 189.0 kg x ha-1 x growing season-1, or 39.3% of the total inorganic particles reaching the ecosystem. The trapped aerosols provided 13.4 kg x ha-1 of soluble nitrogen and 0.91 kg x ha-1 of insoluble nitrogen over the growing season. At the same time, the input of soluble nitrogen from the atmosphere with rainfall to an open area averaged 13.9 kg x ha-1, and the input of insoluble nitrogen with inorganic dusts averaged 1.4 kg x ha-1.     

四川盆地卤水的氢、氧同位素地球化学特征及其成因分类研究

四川盆地地下卤水分布广泛，类型繁多，依据氢、氧同位素地质学方法及其分布规律性，将盆地卤水明确划分出大气水淋滤型、海相沉积型、海相沉积-大气降水叠加型和海相沉积-岩浆水叠加型等四种成因类型。该分类明确，标志明显，有确定的成因涵义，取得了较好的效果。     

化学沉淀法去除水中氨氮的试验研究

研究进行了用Mg2 + 、Mn2 + 分别与PO4 3- 作用去除NH4 + N的试验研究 ,探讨其化学反应机理 ,确定了最佳投药比、反应pH和Mg2 + 、Mn2 + 的协同效应 ,并对广州李坑垃圾填埋场渗滤液中NH4 + N进行了处理 ,其中最大NH4 + N去除率达 96 .1 %。     

An Assessment of Management Practices to Control Nutrient and Pesticide Levels in Vegetable Production Areas in the Rattaphum Catchment, Thailand

The over-use of agrochemicals may have adverse effects on soils along with surface and groundwater. An assessment of alternative management practices to reduce the application of agrochemicals and minimise the pollution of water resources was carried out in the vegetable agro-ecosystem in the Rattaphum Catchment. This paper details the factors that govern the volume of agrochemicals used on high intensity crops in this area, covering the choice of crop and cropping patterns, level of pest and weed infestation and the socio-economic status of farmers such as capital, size of holding and labour availability. Alternative management practices tested included (i) a reduction in the use of pesticides and chemical fertilisers; (ii) the use of bio-insecticides and bio-fertilisers; and (iii) the development of buffer zones near streams to reduce nutrient leaching into surface water systems. The results showed that when compared with bio-insecticides, synthetic insecticides were more effective in controlling major insect pests during chaisim vegetable production and were associated with higher net incomes. The high rate of application of chemical fertilisers in home gardens and commercial farms led to the accumulation of phosphorous and potassium in the top soil, with the traditional method of combining organic and chemical fertilisers producing the highest total nitrogen soil content. A fifty percent reduction in chemical fertilisers in the commercial farms produced the lowest total nitrogen soil content, without any apparent change in crop yield. The three types of tested buffers seem to be effective in reducing runoff and sediment load and were particularly efficient in lowering nutrient leaching to streams; the best results were obtained with an effective length of 2.5 m.     

SOIL EROSION AND GROUND WATER POLLUTION TRADEOFFS FOR NONIRRIGATED FARMING SYSTEMS1

ABSTRACT: Traditional focus on reducing one environmental externality may cause another externality to increase. This article examines the environmental and economic costs of abating soil loss and (or) nitrate leaching through alternative optimal production systems in the nonirrigated farming systems of Northeastern Oregon. Models estimating soil loss and nitrate‐nitrogen leaching rates associated with current production processes, are linked to a Multi‐Objective Programming (MOP) model. The results show that site specific conditions influence the level of abatement expenditures and optimal production strategies to reduce soil loss and leaching rates. Moreover, while existing production strategies are effective in reducing soil loss at little cost, no strategies could be identified to reduce nitrate leaching rate on some soils.     

永定河生态补水下渗对地下水质量的影响

以永定河北京段2019～2020年的生态补水为例,通过室内混合实验和淋滤实验研究河水下渗对地下水质量的影响.结果表明,水化学指标的种类与下渗前相比无变化,水-岩相互作用对指标浓度的改变作用也比较有限,指标的浓度水平总体上介于河水和地下水之间.下渗水对地下水质量的改变作用从根本上取决于河水与地下水的质量差异和河水的补给量...     

Leaching and sorption of neonicotinoid insecticides and fungicides from seed coatings

Seed coatings are a treatment used on a variety of crops to improve production and offer protection against pests and fungal outbreaks. The leaching of the active ingredients associated with the seed coatings and the sorption to soil was evaluated under laboratory conditions using commercially available corn and soybean seeds to study the fate and transport of these pesticides under controlled conditions. The active ingredients (AI) included one neonicotinoid insecticide (thiamethoxam) and five fungicides (azoxystrobin, fludioxonil, metalaxyl, sedaxane thiabendazole). An aqueous leaching experiment was conducted with treated corn and soybean seeds. Leaching potential was a function of solubility and seed type. The leaching of fludioxonil, was dependent on seed type with a shorter time to equilibrium on the corn compared to the soybean seeds. Sorption experiments with the treated seeds and a solution of the AIs were conducted using three different soil types. Sorption behavior was a function of soil organic matter as well as seed type. For most AIs, a negative relationship was observed between the aqueous concentration and the log K_oc. Sorption to all soils tested was limited for the hydrophilic pesticides thiamethoxam and metalaxyl. However, partitioning for the more hydrophobic fungicides was dependent on both seed type and soil properties. The mobility of fludioxonil in the sorption experiment varied by seed type indicating that the adjuvants associated with the seed coating could potentially play a role in the environmental fate of fludioxonil. This is the first study to assess, under laboratory conditions, the fate of pesticides associated with seed coatings using commercially available treated seeds. This information can be used to understand how alterations in agricultural practices (e.g., increasing use of seed treatments) can impact the exposure (concentration and duration) and potential effects of these chemicals to aquatic and terrestrial organisms.