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11.
Parley V. Winger Peter J. Lasier Mark Hudy Dean Fowler M. J. Van Den Avyle 《Journal of the American Water Resources Association》1987,23(3):379-386
ABSTRACT: The Southern Blue Ridge Province, which encompasses parts of northern Georgia, eastern Tennessee, and western North Carolina, has been predicted to be sensitive to impacts from acidic deposition, owing to the chemical composition of the bedrock geology and soils. This study confirms the predicted potential sensitivity, quantifies the level of total alkalinity and describes the chemical characteristics of 30 headwater streams of this area. Water chemistry was measured five times between April 1983 and June 1984 at first and third order reaches of each stream during baseflow conditions. Sensitivity based on total alkalinity and the Calcite Saturation Index indicates that the headwater streams of the Province are vulnerable to acidification. Total alkalinity and p11 were generally higher in third order reaches (mean, 72 μeq/θ and 6.7) than in first order reaches (64 μeq/θ and 6.4). Ionic concentrations were low, averaging 310 and 340 μeq/θ in first and third order reaches, respectively. A single sampling appears adequate for evaluating sensitivity based on total alkalinity, but large temporal variability requires multiple sampling for the detection of changes in pH and alkalinity over time. Monitoring of stream water should continue in order to detect any subtle effects of acidic deposition on these unique resource systems. 相似文献
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本文研究了不同吸水倍率的高分子吸水树脂的相变温度、相变潜热及作为蓄冷材料在35℃环境下的相变时间,并与冰做了对比。结果显示:吸收不同倍率水的高分子树脂。相变温度和相变潜热基本与水相似,随着吸水倍率的增加,相变潜热越接近于水的潜热;在相同条件下放置于隔冷袋中的高分子吸水树脂.在35℃高温环境中,可以维持20℃以下低温5h,比冰多了将近1h,克服了渗漏的缺点,在蓄冷领域表现出了明显的优势。 相似文献
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With the increase of urbanization, municipal solid waste has also increased. Therefore, the need for solid waste management is also increasing compared with earlier decades. Composting is a good option for the recycling of solid waste; however, it produces leachate, which requires proper treatment systems to prevent environmental degradation. Due to high chemical oxygen demand (COD) concentrations in compost leachate, anaerobic treatment is the best option for handling the effluent, and an anaerobic baffled reactor (ABR) is one such anaerobic reactor that can be used for its treatment. Because of high ammonia and heavy metal concentrations, as well as the possibility of sludge washout in ABRs, it is important to use proper media, such as zeolite, which can reduce inhibition effects and sludge washout from the reactor. Anaerobic treatment, especially during the methanogenesis phase, is sensitive, and pH and alkalinity are parameters that influence the treatment. Therefore, adjusting these parameters within a normal range is very important to the proper functioning of anaerobic systems. In this study, a pilot‐scale ABR was used, and the last 4 of the 8 ABR compartments were filled with zeolite. The bioreactor was operated at hydraulic retention times (HRT) of 3, 4, and 5 days, with zeolite filling ratios of 10%, 20%, and 30%, and influent COD concentrations of 10,000, 20,000, and 30,000 milligrams per liter (mg/L). In this study, pH value was 6.43 ± 0.1, 6.96 ± 0.3, and 6.96 ± 0.25 at filling ratios of 10%, 20%, and 30%, respectively. According to the results, in all filling ratios, no significant changes were observed in the pH value when the organic loading rate increased and its amount was within a constant range. Influent alkalinity was equal to 2015 ± 510, 2884 ± 505, and 4154 ± 233 milligrams of calcium carbonate per liter (mg CaCO3/L) at influent COD concentrations of 10,000, 20,000, and 30,000 mg/L, respectively, and in effluent, they were 2536 ± 336, 3379 ± 639, and 4377 ± 325 mg CaCO3/L, respectively. The amount of alkalinity in the effluent increased compared with the alkalinity in the influent. The results show that the amount of alkalinity in the influent and effluent was similar, and the alkalinity enhancement was lower when the filling ratio was increased from 10% to 20%, and 20% to 30%. Comparisons of the results from zeolite with and without biofilm showed that, in cases of zeolite with biofilm, the amounts of silica and oxygen decreased and the amount of carbon increased, and it showed the formation of biofilm on the surface of zeolite. In addition, the absence of sodium in the zeolite with the biofilm indicated that sodium was exchanged with ammonium ions. According to the results, zeolite can be used in anaerobic reactors as a medium, and it also reduces fluctuations in pH and alkalinity at different organic loading rates, providing a normal range for anaerobic treatment. 相似文献
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作物和土壤中DEHP测定的前处理 总被引:2,自引:0,他引:2
介绍农田土壤和农作物样品中微量DEHP测定的前处理方法。该法选用三氯甲烷为抽提液,加入吸水剂进行革取、抽提和浓缩。与北京、丹麦和美国等测试方法相比较,革取时间为0.5—0.7h,缩短了2—11h;溶剂用量为75—90ml,节省溶剂110—1200ml;操作简便、分离效果好;样品中DEHP的回收率除棉花籽实外,其余均达90%左右,变异系数约土3%。该法适宜在酞酸酯监测中推广应用。 相似文献
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饮食业复合油烟吸收剂的研制开发 总被引:1,自引:0,他引:1
分析了饮食油烟的成分 ,结合饮食油烟气的治理方法 ,采用正交设计法进行新型复合油烟吸收剂的实验 ,快速、有效、准确地优化确定了油烟吸收剂的配方和工艺 ,并设计了该吸收剂的油污相溶性、环境毒性、生物降解性实验 ,科学地论证了该产品的性能。结果表明 ,本实验研制的油烟吸收剂能够全面包络、粘合、皂化、附着和分离油烟废气中的油类物质 ,对饮食油烟具有快速、高效、彻底的治理效果 ,而且无毒、易降解。 相似文献
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有机废气的化学吸收是使废物重新进入物质循环 ,避免二次污染并产生经济效益的环境工程方法。针对某市荧光灯厂工艺过程 ,分析研究了废气治理的各种方法 ,提出了用氨水吸收醋酸丁酯废气 ,转化生成乙酰胺和丁醇的吸收净化方案 ,并对生成物质进行回收利用 相似文献
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The area around Chandidongri (latitude 21 deg 02 prime N and longitude 80 deg 37 prime E) is covered by granitic gneisses and amphibolites of the Amgaon Group and granites and rhyolites of the Dongargarh super group. The granites which cover the major portion of the area have been intruded into by a number of dolerite and epidiorite dykes and traversed by a few N–S trending shear zones. A well-known fluorite deposit is located along the Lamtidongri–Kotnapani shear zone. Besides this deposit, the authors have located a few occurrences of fluorite along other shear zones where epidiorite dykes are in association with granites. A number of cases of fluorosis have been reported from those parts of Rajasthan and Andhra Pradesh which are covered by granitic rocks and also from the eastern parts of Bhandara district which are adjacent to the area described here. The Chandidongri area is mainly covered by granitic rocks, which at places show the presence of fluorite mineralisation. Taking into consideration these facts, the authors have investigated the area to study the cases of fluorosis if any, and the impact of geology and fluorite mining on the water quality in this region. During the survey, we have not come across any cases of fluorosis in this region. The pH is more than 7 and the fluoride concentration is within the permissible limit. 相似文献