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排序方式: 共有189条查询结果,搜索用时 15 毫秒
41.
Environmental Science and Pollution Research - A large amount of ammonia volatilization from the agricultural system causes environmental problems and increases production costs. Conservation...  相似文献   
42.
Environmental Economics and Policy Studies - We capitalize on access to plant-level data in examining the changes in emissions of biochemical oxygen demand (BOD), total suspended solids (TSS), and...  相似文献   
43.
This paper analyses the complex interactions among the seventeen sustainable development goals (SDGs) and presents them in a hierarchical framework using interpretive structural modeling technique. The driving and dependence powers of each of these goals have been ascertained to help the developing and least developed countries improve their strategic orientation for a particular goal within a given time frame. This would also help them in prioritizing their resource allocations on a specific SDG by focusing on its hierarchical ranking on one hand and driving and dependence powers on the other.  相似文献   
44.
Summary Human beings use huge quantities of water every day for drinking, cleaning and various cultural functions and dispose of it as wastewater within sewage. With increase in population, the magnitude of this waste is multiplying enormously and beyond the recycling capacity of local ecosystems to become a major health and environmental hazard. Re-use of wastewater for afforestation purposes in the form of sewage silviculture combines the dual benefit of water conservation with environmental sanitation. Such experiments are being carried out at the World Forest Arboretum in Jaipur, Rajasthan, India. Biological treatment of the sewage before application, to improve its irrigational quality, to remove harmful chemicals and to prevent the risk of these passing into the human food chain is being undertaken. The aquatic weeds Lemna and Eichhornia are being used to purify the wastewater. The technique is both economically viable and ecologically sustainable.Dr Rajiv K. Sinha is assistant professor in Human Ecology at the University of Rajasthan.  相似文献   
45.
The search for new solvents is often driven by (a) the need to replace solvents whose continued use pose a threat to environmental health and safety, (b) the needs of new applications and processing requirements, (c) a response to changing environmental regulations and (d) a response to market demands. For example, many traditional solvents are on the environmental ‘hit list’ and are to be phased out within the next few years. In particular, cleaning solvents, which are used as blanket washes in the lithographic printing industry present a number of environmental concerns including health and safety. To respond to these concerns and more importantly to respond to rapidly changing operational requirements and market forces, there is a need for efficient and systematic strategies for ‘just in time’ optimal design of solvent alternatives. A good strategy has to consider simultaneously, performance objectives, system interactions and environmental constraints. The object of this paper is to identify and discuss the issues in the design of cleaning solvents (blanket washes) in the printing industry and how environmental and health factors can be accounted for. We do this in the context of a framework for product design. As a proof-of-concept, blanket wash solvents are designed.  相似文献   
46.
印度的大多数采矿活动都发生在生态敏感地区.本文讨论了一项回填(即用挖出来的物质填矿井)研究计划的结果.在一些情况下,由于技术限制,回填法的使用不得不被部分或全部放弃.也有许多费用方面的考虑.制定一条国家改造采矿用地战略是最根本的策略.  相似文献   
47.
Sinha S  Yoon Y  Amy G  Yoon J 《Chemosphere》2004,57(9):1115-1122
Polymeric forms of metal coagulants in water treatment have become increasingly used due to their wider availability and reduction in cost. These specialized coagulant forms and products are claimed by manufacturers to be superior to conventional coagulants in particulate and/or organic removal with inherent advantages of lower alkalinity consumption and lesser sludge production. However, due to their proprietary nature, little is known about their chemical composition. To determine and understand the effectiveness of these alternative coagulants, a comprehensive study was undertaken to characterize metal coagulants, and to comparatively evaluate them on a well-characterized source water. The objective of this study was to provide a scheme for utilities that could be employed as a screening process and a method of selecting an appropriate coagulant based on raw water characteristics and insight into the coagulatability of the source water. Characterizations of coagulants included: (i) active metal content, (ii) anion content, (iii) acidity, (iv) alkalinity consumption, (v) charge reversal by colloidal titration, and (vi) molecular weight determination. A total of five poly-aluminum chlorides (PACl), along with a conventional coagulant (aluminum sulfate or alum) were evaluated. Results show that through the characterization scheme, an effective coagulant (conventional versus alternative) and coagulant type (among various PACl) can be chosen before undertaking time-consuming bench or pilot-scale evaluation.  相似文献   
48.
Singh KP  Mohan D  Sinha S  Dalwani R 《Chemosphere》2004,55(2):227-255
Studies were undertaken to assess the impact of wastewater/sludge disposal (metals and pesticides) from sewage treatment plants (STPs) in Jajmau, Kanpur (5 MLD) and Dinapur, Varanasi (80 MLD), on health, agriculture and environmental quality in the receiving/application areas around Kanpur and Varanasi in Uttar Pradesh, India. The raw, treated and mixed treated urban wastewater samples were collected from the inlet and outlet points of the plants during peak (morning and evening) and non-peak (noon) hours. The impact of the treated wastewater toxicants (metals and pesticides) on the environmental quality of the disposal area was assessed in terms of their levels in different media samples viz., water, soil, crops, vegetation, and food grains. The data generated show elevated levels of metals and pesticides in all the environmental media, suggesting a definite adverse impact on the environmental quality of the disposal area. The critical levels of the heavy metals in the soil for agricultural crops are found to be much higher than those observed in the study areas receiving no effluents. The sludge from the STPs has both positive and negative impacts on agriculture as it is loaded with high levels of toxic heavy metals and pesticides, but also enriched with several useful ingredients such as N, P, and K providing fertilizer values. The sludge studied had cadmium, chromium and nickel levels above tolerable levels as prescribed for agricultural and lands application. Bio-monitoring of the metals and pesticides levels in the human blood and urine of the different population groups under study areas was undertaken. All the different approaches indicated a considerable risk and impact of heavy metals and pesticides on human health in the exposed areas receiving the wastewater from the STPs.  相似文献   
49.
Release of amine products from azo compounds is of considerable interest, since most of the metabolized amine products have toxic and carcinogenic characters. Moreover, most of the azo dyes are extensively used as coloring agents in inks, textiles, leathers, food and pharmaceutical industries. The present study emphasis on the quantification and comparison of amines released from water soluble dyes by (i) extra cellular protein (ECP) of Streptomyces sp. SS07 and by (ii) chemical methods. It has been observed that both the methods release considerable quantities of similar type of amine products. Release of amine compounds by ECP and chemical reduction in acid and alkaline sweat medium from a leather garment sample was also assessed. ECP (0.7852 mg protein/mg of ECP) releases benzidine and 4-amino biphenyl from Direct Black 38 and Direct Brown 1 as stable products at pH 9.2 and at 37 degrees C for a contact period of 24 h. On comparison with chemical reduction, it was observed that about 5-20% increase in the release of amine products by ECP was observed. However, more than 60% of amine products were released by chemical method from leather garment samples than direct treatment with ECP.  相似文献   
50.
Most frequently encountered freshwater cyanobacterial toxin is Microcystin-LR (MC-LR). Microcystins released from cells into water have been responsible for the death of humans, domestic and wild animals. Removal of microcystin by active carbon has been one of the best methods available so far. This study evaluates three grades of active carbon namely 40, 60 and 80 CTC for their removal efficiency of MC-LR from contaminated water. Kinetics of toxin removal was studied in time course experiments. Protection in mouse model was studied for the samples after the adsorption. Toxin quantitation was done by HPLC method. The MC-LR concentration after 24 hr treatment with 40, 60 and 80 CTC carbons were 4.8, 3.3 and 1.3 microg/ml respectively from an initial concentration of 5.2 microg/ml. Protection in mouse bioassay was seen after 48, 24 and 2 hr of adsorption time respectively for 40, 60 and 80 CTC carbons. 80 CTC carbon was found to be most efficient in removing MC-LR from contaminated water.  相似文献   
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