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排序方式: 共有207条查询结果,搜索用时 15 毫秒
1.
M. M. Jordán S. Pina F. García-Orenes M. B. Almendro-Candel E. García-Sánchez 《Environmental Geology》2008,55(2):453-462
The ecologic restoration criteria in areas degraded from extraction activities require making use of their mine spoils. These
materials do not meet fertility conditions to guarantee restoration success and therefore, need the incorporation of organic
amendments to obtain efficient substratum. Reducing the deficiencies in the organic material and restoration material nutrients
with the contribution of treated sewage sludge is proposed in this work. This experiment was based on a controlled study using
columns. The work was conducted with two mine spoils, both very rich in calcium carbonate. The first mineral, of poor quality,
came from the formation of aggregates of crushed limestone (Z). The other residual material examined originated in limestone extraction, formed by the levels of interspersed non-limestone
materials and the remains of stripped soils (D). Two treatments were undertaken (30,000 and 90,000 kg/ha of sewage sludge), in addition to a control treatment. The water
contribution was carried out with a device that simulated either short-duration rain or a flooding irrigation system in order
to cover the surface and then percolate through the soil. The collection of leached water took place 24 h after the applications.
Different parameters of the leached water were determined, including pH, electrical conductivity, nitrate anions, ammonium,
phosphates, sulphates and chlorides. The values obtained for each irrigation application are discussed, and the nitrate values
obtained were very elevated. 相似文献
2.
3.
A. J. O'Neill T. S. Galloway M. A. Browne A. Dissanayake M. H. Depledge 《Marine environmental research》2004,58(2-5):327
Increasing numbers of industrial, agricultural and natural chemicals are present in sewage effluent and are known to elicit toxic effects in laboratory exposures, but little is known of their combined sub-lethal effect in the field. In this study, a combination of esterase activity and ventilation rate assays was performed to determine the neurological and physiological function of the freshwater crustacean Asellus aquaticus (L.) at sites above and below a sewage treatment works (STW). Cholinesterase and carboxylesterase activities were significantly inhibited (n=8, P<0.05) and ventilation rates increased (n=8, P=0.0001) in A. aquaticus at STW sites compared to those from reference sites, indicating a decrease in neurological and physiological function. The ecological relevance of these findings for the population dynamics of the organisms in the field is discussed. 相似文献
4.
Savitri Tripathi Vandana Parth Phani Homeshwari M. Vittal Babu N. Murthy N.N. Sorlie J.E. Govil P.K. 《中国地球化学学报》2006,25(B08):117-118
Permeable Reactive Barrier (PRB) is an emplacement of inert material (s) in the subsurface, designed to intercept a contaminated plume, provides a preferential flow path through the reactive media, and transforms the contaminant into environmentally acceptable forms to attain concentration remediation goals at the discharge of the barrier. The phenomena, which help in remediation within PRB, are adsorption/sorption, precipitation, oxidation/reduction and biodegradation. Various materials like zero-valent iron, zero-valent bi-metals, natural zeolites, organic carbon, fly ash, zeolites, limestone, activated alumina, apatites, etc. have been tried by many researchers to remove organic and inorganic contaminants. In USA, Canada, and many European countries commercial full-scale and pilot scale PRBs are successfully working. The design and installation of full scale PRBs needs laboratory treatability and dynamic flow column experiments? The concept of PRB is being applied to treat contaminated surface water in the Katedan industrial area, Hyderabad, India. National Geophysical Research Institute (NGRI), Hyderabad, India, conducted systematic studies in collaboration with Norwegian Geotechnical Institute (NGI), Norway, to develop PRB technique to decontaminate the surface water pollution due to industrial effluent. A site assessment study in the Katedan Industrial Area, were carried out and water, soil and sediment from the lakes of the area were found to be polluted with high concentrations of heavy metals like As, Pb, Cr, Cd, Ni, etc. Adsorption studies at NGRI with synthetic samples and in-situ industrial effluent using different reactive media for removing contaminants like arsenic, chromium, cadmium, copper, nickel, lead and zinc have been carried out and yielded satisfactory results. The performance of zero-valent iron and limestone is encouraging in removing As, 相似文献
5.
This paper presents the results of investigation on uptake of radioactive species 90Sr and 137Cs present in the liquid effluents from nuclear processing plants. Chemical precipitation process is adopted to remove radioactivity from the effluents with low and intermediate level of activity. In this process, radioactive 90Sr and 137Cs are co-precipitated along with copper ferrocyanide, ferric hydroxide and either calcium phosphate or barium sulphate. These precipitates being fine in size require flocculation for enhanced settling rate in clarifier/thickener. The flocculation by some selected high molecular weight polyacrylamide based polymers has improved the uptake of radioactive metal ions. The adsorption of these radioactive species has been found to increase in the presence of these flocculants thereby improving the decontamination factor (DF). While flocculating the precipitates, there may be some complex formation with Sr2+/Cs+, flocculant and the substrate. This has enhanced the uptake of the radioactive metal ions from the liquid component. The plant trials have indicated the improvement of DF value due to flocculation by cationic flocculant. 相似文献
6.
River Vrishabhavathy, a tributary of Cauvery River was studied for 12 physico-chemical parameters at four sites over a distance
of 50 km for a period of 2 years (1999–2001) at monthly intervals. Water was faintly alkaline, with pH showing negative correlation
with temperature. The dissolved oxygen content increased downstream with negative correlation to biological oxygen demand
(BOD), chemical oxygen demand (COD) and turbidity. Bicarbonate alkalinity was very low compared with carbonate alkalinity.
Carbonate alkalinity, total hardness, total dissolved solids, total suspended solids, electrical conductivity, BOD and COD
decreased downstream, with an upward trend in the middle reaches due to the introduction of raw sewage. The seasonal and yearly
trends are also discussed. The river is a sewer collector undergoing self-purification. 相似文献
7.
Meretta Lake (Resolute Bay, Cornwallis Island, Nunavut, Canada) is a high arctic lake that received raw sewage for almost 50 years from the Canadian Department of Transport Base. The lake was sampled from 1968–72 during the International Biological Programme, as part of the Char Lake Project. As the number of users at the Transport Base declined throughout the 1990s, so too did the lake's nutrient levels, and Meretta Lake is now classified as oligotrophic. A previous diatom-based paleolimnological study revealed marked species assemblage shifts coincident with sewage inputs beginning in the late 1940s; however, because the core was taken at a time when nutrient levels were still relatively high (i.e., 1993), the diatom record did not yet track any signs of recovery. In this present study, we examined fossil diatom assemblages from a sediment core taken in 2001. Our results indicate a shift to the pre-impact diatom assemblages in the most recent sediments, indicating that the paleolimnological record is tracking the decreased nutrient inputs to this high arctic lake, and confirms that no significant lags exist in these largely ice-covered lakes. 相似文献
8.
Study of Sorptional Properties of the Cation Exchanger KB-2M with Macroreticular Structure for Recovery of Zinc Ions from Sewage and Rinsing Water Although a number of ion-exchange methods have been employed for the recovery of some transition metals from industrial effluents, knowledge about ion-exchange resins with macroreticular structure is poor. The present paper describes the mechanism of sorption on such exchangers and their application for recovery of zinc from sewage rinsing water. Ion exchanger of macroreticular structure are polymers with long-chained cross-linking agents. We have synthesized carboxylic ion-exchange resins by hydrolysis of copolymerisates of methyl acrylate with different cross-linking agents: divinylbenzene, divinyl sulfide, divinyl ester of ethylene glycol and divinyl ester of di- or triethylene glycol. The sorption process on modifications of the carboxylic resins KB-2 of various structure was studied with different methods: potentiometric titration, infrared spectroscopy, electron microscopy, X-ray structural analysis. The initial zinc concentration in rinsing water was 0.05 mol/L at pH from 3 to 6. For the sorption, 0.2…1.0 g of resin were equilibrated with 100 mL of zinc solution. After equilibrium (12 h), the resin was separated from solution. The zinc ions were determined by atomic absorption spectrometry after stripping with 100 mL of 10% sulfuric acid. The distribution ratio D was calculated (D: mmole of Zn sorbed per gram of resin divided by mmole of Zn per millilitre of solution). By means of infrared spectroscopy, the mechanism of sorption of zinc ions from rinsing water was determined. There may be a possibility of the formation of complexes in the cation-exchange resin phase. It was found out in this paper that the cation-exchanger KB-2M of macroreticular structure is the most effective for the sorption of the Zn2+-ions from sewage and rinsing water. 相似文献
9.
Heavy metals in sediments of the Tecate River, Mexico 总被引:1,自引:0,他引:1
F. T. Wakida D. Lara-Ruiz J. Temores-Peña J. G. Rodriguez-Ventura C. Diaz E. Garcia-Flores 《Environmental Geology》2008,54(3):637-642
Ten sites along the Tecate River, Mexico were sampled to evaluate the cadmium, lead, nickel and chromium concentrations in
sediments. The result shows contamination for cadmium in most of the sites, where two sites were class 4 (polluted to strongly
polluted) according to geoaccumulation index proposed by Muller. Two sites were found polluted for all the heavy metals analyzed
(Cr, Cd, Pb and Ni), indicating the effect of anthropogenic activities. A correlation between Ni and Cd concentration had
been found indicating a common source. These metals are usually used in electroplating industry. The results of this study
can be used for decision makers to prioritize measures to control the pollution for these metals. 相似文献
10.
中国多数红树林陆地边缘存在着大量的养虾池塘。这些养虾池塘可通过:(1)换塘外排废水,(2)清塘直排污泥影响周围的红树林。本研究共包含两个实验,来探讨这两种类型的排污对秋茄幼苗生长的影响。实验一模拟虾池常规换塘情况,研究换塘废水对秋茄幼苗生长的影响。实验二设置四种虾池清塘污泥沉积厚度(0 cm,2 cm,4 cm,8 cm),研究虾池清塘污泥的累积效应对秋茄幼苗生长的影响。结果如下:在5,15和25三种盐度下,虾池换塘废水未对秋茄生长指标造成显著影响;而清塘污泥对秋茄生长的影响与其沉积厚度有关,大多数生长参数在污泥沉积厚度为4 cm时呈现最大值。秋茄幼苗在适量的沉积厚度下加速了生长,且本实验秋茄幼苗对虾池清塘污泥的耐受性为沉积厚度8 cm。 相似文献