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1.
本文简要介绍了住宅厨房卫浴间管线综合设计及接口技术,并对住宅厨房卫浴间内管线布置及接口设计提出要求,以及对这些接口与相关设备的连接问题提出一些建议。 相似文献
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采用3种工业废弃物,配制水泥净浆试件,对比研究了标准养护和碳化作用条件下,水泥制品中重金属元素的溶出性能经时变化规律,分析了碳化作用对重金属溶出的影响机理。结果表明,重金属的溶出符合Fick扩散第二定律;溶出主要发生在前14 d,而后趋于平缓,21 d后溶出量极少;工业废弃物的重金属含量会显著影响其平均扩散系数和总溶出量。水泥基材料的高碱性环境、致密的孔隙结构以及稳定的水化产物形态是重金属元素稳定固化的重要保障,碳化由表及里地降低了材料的碱度和密实度,引起大部分水化产物分解,使得碳化作用后水泥试件的重金属溶出量和平均扩散系数增加。 相似文献
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Partitioning of trace metals before and after biological removal of metals from sediments 总被引:7,自引:0,他引:7
Metal removal by biological solubilization in three strongly contaminated sediments was carried out in a two-liter stirred bioreactor. Biological treatment yielded metal removal efficiencies in the range of 11-30%, 43-57%, 60-79%, 61-90%, 18-21%, 0-10% for Pb, Cu, Zn, Cd, Ni and Cr, respectively. The treated sediments were then rinsed with a NaCl solution (0.5 M), resulting in an increase by nearly 47% in Pb removal for the three sediments, while for other metals (Cu, Zn, Cd, Ni, Cr), the NaCl rinse did not seem to allow any significant increase in metal solubilization. A standard procedure of sequential selective extraction (SSE) was applied to the sediments before and after each treatment. With regard to Pb, Zn and Cd, the carbonate bound fractions (2/3 sediments) represented 18-42% of metals prior to treatment, while the iron and manganese oxides bound fraction constituted 39-60% of metals for the three sediments. Between 90 and 100% of Pb, Zn and Cd removed by the process came from the fractions bound to carbonates and from those bound to Fe and Mn oxides. The organic matter and sulfide bound fractions contained 65-72% of total Cu present before treatment and the process removed, on average, 63% Cu present in this fraction. In contrast, Ni and Cr were found mainly in the residual fractions (50-80%). Finally, this biological treatment did not solubilize Cr appreciably, while removal of Ni mostly originated from the carbonate and Fe/Mn oxides fractions (70-80%). 相似文献
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以某滑雪度假洒店工程为研究背景,对滑雪餐厅厨房、咖啡厅厨房及饼房等酒店厨房内常见的各种用电设备进行了列举分析,提出了后期进行深化设计时应注意的要点,以供同类工程参考借鉴。 相似文献
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Distribution of some trace metals in Lochnagar, a Scottish mountain lake ecosystem and its catchment 总被引:9,自引:0,他引:9
Anthropogenic trace metals enter the entire ecosystem of Lochnagar solely through atmospheric deposition. Trace metals, including Hg, have been monitored in atmospheric deposition and lake water, and measured in catchment vegetation, aquatic plants and zooplankton, revealing contamination levels in the ecosystem. Furthermore, 17 sediment cores were taken from different areas of the lake. Hg, Pb, Cd, Zn and Cu were analysed in all the cores, which show that the sediments have been heavily contaminated by these trace metals since the 1860s. The distribution of trace metals in the lake sediments was found to be heterogeneous, with concentrations in the surface sediments varying significantly: 110-250 ng/g, 100-360 microg/g, 39-180 microg/g, 0.3-1.9 microg/g and 8-25 microg/g for Hg, Pb, Zn, Cd and Cu, respectively. Trends in the concentration profiles for different trace metals in the same core are different, as are the trends of the profiles for the same metal in different cores. Hence, a single sediment core cannot represent the pollution history of the whole lake. As the soils and sediments contain a high proportion of plant debris and the debris has a high affinity for Hg, resulting in Hg enrichment. Hg was measured in plant debris (> 63 microm) separated from catchment soils and lake sediments. Plant debris may play an important role in storing and transferring Hg in this ecosystem. 相似文献
6.
The trace concentrations of a number of metals including chromium, zinc, lead, vanadium and copper have been determined in intertidal sediments from the south bank of the Humber estuary. The values have been associated with the particle size and organic carbon content of the sediments and the levels of metal concentration are compared generally with levels found elsewhere in estuarine and river sediments. The high values and trends in metal content of the sediments compared with “natural” levels may be ascribed to industrial and domestic effluents discharged into the estuary from a number of outfalls within the area. Methods of analysis to distinguish between natural and effluent metal contents of sediments are discussed. 相似文献
7.
The influence of soluble organic matter from municipal solid waste compost on trace metal leaching in calcareous soils 总被引:8,自引:0,他引:8
The use of municipal solid waste (MSW) compost as fertilizer may cause increased leaching due to its high content of trace metals and thus pose a threat to groundwater quality. The effect of MSW compost application on trace metal leaching in calcareous soils has been studied in soil column experiments under laboratory conditions using three soils from the study area in the Gaza Strip and Israel. Higher levels of organic matter in solution (TOMS), nitrate, and the trace metals Cu, Ni and Zn were found in the leachates of a sandy soil and, to a lesser extent, a loamy soil, to which MSW compost had been applied at a rate of 65 Mg ha(-1) (dry weight basis). Nevertheless, the majority of water-soluble trace metal species from compost accumulated in the topsoil rather than washing out, with the exception of aqueous Ni species. Ni concentrations exceeded the maximum allowable limits for drinking water (in Germany: 50 microg l(-1)) at peak times in the leachates from sandy soil, while all other trace metals remained far below the corresponding limits. The highest absolute concentrations of trace metals were found for the leaching of Cu from compost-amended sandy soil (100 microg l(-1)). For Cd, Pb and Hg no evidence of downward movement was found in any assay. Gel filtration studies of the collected soil leachates showed that all trace metals encountered in the leachates existed mostly as organic complexes. In sandy soil most of the water-soluble organic matter added with the compost had leached from the rootzone after a year's equivalent of rainfall, while TOMS mobility was greatly reduced in the loamy soil. The makeup of the TOMS in the sandy soil and its metal-binding capacity was strongly influenced by compost-derived dissolved organic matter (DOM) as observed by FTIR spectrometry. Hence the vertical displacement of trace metals (Cu, Ni, Zn) in these calcareous soils seemed to result primarily from the presence of mobile metal-organic complexes in the soil solution after compost addition. Further studies are required to validate these findings in the field, especially to assess the risk of Cu and Ni leaching in sandy soil. 相似文献
8.
The concentration of some trace elements has been measured in samples of breast milk collected from several subjects over a period of about 1–3 months starting 15 days post-partum.A decrease of Zn concentration during the lactation period was observed in all subjects. The marked relation existing between dietary intake and milk content of trace elements is confirmed by the finding that Cs concentration in diet, fresh waters and human milk samples from Latium were one to two orders of magnitude higher than those measured in a small town in the south of Italy. In most subjects Cs, Zn, Rb, Fe concentrations during the same day, and in the same feed, are fairly constant. Larger variations are observed for concentrations of Co, Sc, and Sb. 相似文献
9.
Lutz Brügmann 《The Science of the total environment》1984,37(1):41-60
Various approaches, such as bioassays, computer-assisted modelling and direct measurement following physical separation are currently being used to investigate the speciation of trace metals in sea water. The electrochemical techniques used successfully as a necessary prerequisite for the experiments involved include conventional polarography, anodic stripping voltammetry (ASV) and potentiometry. Differential pulse anodic stripping voltammetry (DPASV) using mercury film electrodes enables direct studies in ultratrace levels present in non-contaminated ocean waters.By varying the conditions of the sample chemistry and electroanalysis it is possible to characterize metal-organic interactions. This is demonstrated in the case of natural sea water samples subjected to ASV diagnosis. Differences in the Pb and Cu values yielded for Baltic waters by two methods based on DPASV and AAS are discussed with regard to speciation.An analysis of the existing literature is used to briefly summarize the needs of future research. Important problems requiring a more precise quantitative analysis include the adsorption of organics on electrodes and the kinetics and thermodynamic constants of chelates with special regard to the physico-chemical nature of metal-humic substances. The introduction of new and improved electroanalytical techniques and equipment for speciation studies is strongly recommended. 相似文献
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Discarded automotive tires, a solid waste disposal problem of enormous proportions, may provide the answer to another environmental headache—the removal of trace metals from wastewaters.Experiments were designed to evaluate the feasibility of using discarded automotive tires in conjunction with time to remove aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, silver and zinc from aqueous solutions.Continuous bench-scale studies showed that removals in excess of 99.5 per cent for most of the metals can be achieved by treatment with lime and discarded automobile tires. 相似文献
12.
Several extractants were used to further study the leaching rate of lead from unplasticized poly (vinyl chloride) pipes under different temperatures. The effects of the concentration of extractant and extraction time on the leaching of lead were also investigated. The results show that the complexing agent (EDTA) extracts much more lead from the pipes than other extractants. The study also shows that the extrusion temperature of the pipe affects the leaching rate of lead by tap water, nitrate, sulphate, carbonate, phosphate and EDTA. The lower rate of lead extraction is obtained from the pipe when extruded at 190°C as compared to those extruded at 170 to 180°C. 相似文献
14.
In the present investigation, the flocculation of dissolved Cd, Cu, Ni, Pb, Mn and Zn with initial concentrations of 1, 2.5 and 5 mg/L in Tadjan River water during mixing with the Caspian Sea water has been studied in order to determine estuarine capacity to remove dissolved metals in the accidental contamination of the river. The flocculation process was investigated on a series of mixtures with salinities ranging from 0.1 to 11 p.p.t. The flocculation rates were indicative of the nonconservative behaviour of Cd, Cu, Ni, Pb, Mn and Zn during estuarine mixing. The order of the final flocculation rate of dissolved metals at 1, 2.5 and 5 mg/L of initial metal concentrations in the river water is as follows:Cu (99%)>Cd (95%)>Zn (88%)>Mn (85%)>Pb (83%)>Ni (73%), Cu(95.6%)>Pb(92.4%)>Cd (90%)>Zn(88.4%)>Mn (81.6%)>Ni(78.8%) and Cd (100%)>Cu(88%)>Ni (85.2%)>Pb (84%)>Zn (83.2%)>Mn (81.2%), respectively. The results also revealed that removal of dissolved metals is not influenced by pH changes and precipitation processes. The flocculation rates revealed that the overall dissolved metal pollution loads may be reduced to about 70% up to about more than 90% during estuarine mixing of Tadjan River with the Caspian Sea water. 相似文献
15.
Isao Aoyama 《Water research》1978,12(10):837-842
This paper describes the importance of a food chain to estimate the concentration of heavy metals from the viewpoint of nutrition ecology.The experiments were performed to investigate the effects of the following experimental conditions on the uptake of heavy metals by a predator, using 137Cs as a tracer; ration size per day, feeding interval and the change in weight of the predator fish. Top minnows (Oryzias latipes) were used as preys and Golden astro (Astronotus ocellatus) as predators. The preys were raised without feeding in an aquarium and the predators were fed top minnows.The set of results showed that (1) the concentration of a metal in predator fish increased with the ration size, (2) the feeding interval had no effect on the uptake of the metal by fish under the experimental conditions performed, and (3) the concentration in the growing fish was suppressed increasing in value with the increase of its weight. They suggest the importance of generalization of the experimental food conditions when the study on the concentration process of heavy metals through a food chain is performed. The paper also deals with the compartment model applied to the concentration process of the metal by a fish. The theoretical results depicted well the experimental ones. 相似文献
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R. K. Somashekar M. D. Kulashekaran M. Satishchandra Prabhu 《The International journal of environmental studies》2013,70(3-4):277-280
The comparative toxicity of heavy metals such as Cu, Co, Ni and Zn to some plant pathogenic and non‐pathogenic fungi has been assessed. The growth of mycelia in substrate treated with metals remained dose‐dependent, and at higher concentrations total inhibition was noticed. Sporulation was delayed in all the cases, although there occurred a vigorous growth of mycelia after a few days of incubation. The possibility of using fungi to monitor heavy metal pollution has been discussed. 相似文献
18.
Concentration and fate of trace metals in Mekong River delta 总被引:4,自引:0,他引:4
In the Mekong River delta and its associated coastal zone trace elements concentrations (Cd, Cu, Ni and Pb) were measured in the dissolved phase (DP) during dry (March 1997) and wet (October 1997) seasons. As, Co, Cr, Ni, Pb, and Al were also measured in suspended matter (SM) and total and organic carbon, trace elements (Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn) and macro elements in superficial sediments (S). Trace metal concentrations in DP and SM during the contrasting hydrological conditions were generally found within the range observed for uncontaminated environment. The average DP concentrations (nM) in the river for March and October are: Cd 0.03 and 0.09, Cu 15 and 14, Ni 7.8 and 8.4, Pb 0.51 and 0.50, respectively. In general there is no significant difference between the concentrations observed during dry and wet season. The evolution of the DP trace metal concentration in the surface water within the salinity gradient suggests no noticeable exchange between the particulate and dissolved phase. This result is in good agreement with those observed in most plume structures studied so far. The average concentrations in the SM (microg/g) (March, October) at the river end-member are: As (24; 11), Co (17; 9), Cr (49; 29), Ni (32; 18), Pb (42; 19) and Al (113,000; 67,000), respectively. All trace elements show higher concentrations in March than in October, with an average increase of two times. This is essentially related to grain size effect since smaller particles were supplied during dry season. These differences are not reflected in the mixing zone, which integrates the seasonal variations. The concentration of major elements (C total, C organic, Si, Al, Ca, K, Fe, Mg, Ti), trace elements (Pb, Zn, Cu, Ni, Mn, Cr, Cd, Hg) in superficial sediments, show similar values during the two seasons and does not show any important variation with depth, indicating either a very fast sedimentation rate and/or the absence of any significant contamination. 相似文献
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Contribution of trace metals from atmospheric deposition to stormwater runoff in a small impervious urban catchment 总被引:4,自引:0,他引:4
The contribution of atmospheric deposition to emissions of trace metals in stormwater runoff was investigated by quantifying wet and dry deposition fluxes and stormwater discharges within a small, highly impervious urban catchment in Los Angeles. At the beginning of the dry season in spring 2003, dry deposition measurements of chromium, copper, lead, nickel, and zinc were made monthly for 1 year. Stormwater runoff and wet deposition samples also were collected, and loading estimates of total annual deposition (wet+dry) were compared with annual stormwater loads. Wet deposition contributed 1-10% of the total deposition inside the catchment, indicating the dominance of dry deposition in semi-arid regions such as Los Angeles. Based on the ratio of total deposition to stormwater, atmospheric deposition potentially accounted for as much as 57-100% of the total trace metal loads in stormwater within the study area. Despite potential bias attributable to processes that were not quantified in this study (e.g., resuspension out of the catchment or sequestration within the catchment), these results demonstrate atmospheric deposition represents an important source of trace metals in stormwater to waterbodies near urban centers. 相似文献