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601.
采用厌氧流化床(AFB)-序批式反应器(SBR)工艺处理蓝皮制革工业废水。分别考察了水力停留时间(HRT)、容积负荷对厌氧流化床以及曝气时间、污泥浓度、溶解氧浓度对SBR反应器处理效果的影响。试验结果表明,AFB将实验废水的BOD_5/COD(B/C)值由0.19~0.26提高至0.35~0.42,有效提高了其可生化性;在进水COD浓度为1 700~1 890 mg/L、HRT为1 d、容积负荷为1.792 kg COD/(m~3·d)时,COD去除率达65.2%~68.5%,且具有良好的抗冲击负荷能力。SBR在进水COD浓度为628~712 mg/L、污泥浓度为2.9 g/L、曝气时间为10 h、溶解氧浓度为2 mg/L工况下,COD去除率达87.6%,NH_3-N去除率达93.6%,处理后出水水质符合污水综合排放标准(GB 8978-1996)中的一级标准要求。 相似文献
602.
Soil inventories of anthropogenic radionuclides were investigated in altitudinal transects in 2 French regions, Savoie and Montagne Noire. Rain was negligible in these 2 areas the days after the Chernobyl accident. Thus anthropogenic radionuclides are coming hypothetically only from Global Fallout following Atmospheric Nuclear Weapon Tests. This is confirmed by the isotopic signatures (238Pu/239+240Pu; 137Cs/239+240Pu; and 241Am/239+240Pu) close to Global Fallout value. In Savoie, a peat core age-dated by 210Pbex confirmed that the main part of deposition of anthropogenic radionuclides occurred during the late sixties and the early seventies. In agreement with previous studies, the anthropogenic radionuclide inventories are well correlated with the annual precipitations. However, this is the first time that a study investigates such a large panel of annual precipitation and therefore of anthropogenic radionuclide deposition. It seems that at high-altitude sites, deposition of artificial radionuclides was higher possibly due to orographic precipitations. 相似文献
603.
E. Tipping J.J. Rothwell A.J. Lawlor 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1521-1529
Simulation modelling with CHUM-AM was carried out to investigate the accumulation and release of atmospherically-deposited heavy metals (Ni, Cu, Zn, Cd and Pb) in six moorland catchments, five with organic-rich soils, one with calcareous brown earths, in the Pennine chain of northern England. The model considers two soil layers and a third layer of weathering mineral matter, and operates on a yearly timestep, driven by deposition scenarios covering the period 1400-2010. The principal processes controlling heavy metals are competitive solid-solution partitioning of solutes, chemical interactions in solution, and chemical weathering. Agreement between observed and simulated soil metal pools and surface water concentrations for recent years was generally satisfactory, the results confirming that most contemporary soil metal is from atmospheric pollution. Metals in catchments with organic-rich soils show some mobility, especially under more acid conditions, but the calcareous mineral soils have retained nearly all anthropogenic metal inputs. Complexation by dissolved organic matter and co-transport accounts for up to 80% of the Cu in surface waters. 相似文献
604.
One century sedimentary records of polycyclic aromatic hydrocarbons, mercury and trace elements in the Qinghai Lake, Tibetan Plateau 总被引:2,自引:0,他引:2
Xiaoping Wang Handong Yang Xin Zhao Simon Turner 《Environmental pollution (Barking, Essex : 1987)》2010,158(10):3065-3070
Sediments from a remote lake of northeastern Tibetan Plateau were analyzed for polycyclic aromatic hydrocarbons (PAHs) and trace metals. USEPA priority PAHs, ranged from 11 in 1860 to 279 ng g−1 in 2002, while, the deposition fluxes were in the range of 0.2-11.4 ng cm−2 yr−1. Similarly, from 1860 to 2002, an increased trend of Hg flux was observed (0.5-3.2 ng cm−2 yr−1). Remarkable increase of PAHs and Hg concentration began from 1970, nearly the same period of the “Reform and Open” Policy had been embarked (1978) in China. Good correlations were found between concentrations of Pb, Zn, Cd, As, Hg, and PAHs, which suggested the sources of these chemicals in the sediment is analogous, likely from anthroprogenic sources. Based on isomer ratios, PAHs in core were dominantly from the incomplete combustion of coal. Owing to the proximity to dust source area (Qaidam Basin) and the close association between PAHs, Hg, Pb, and particle matters, atmospheric dust-transport and deposition might be the main pathways that pollutants enter into Qinghai Lake. 相似文献
605.
In recent decades, mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals. Since 1990, the European moss survey has been repeated at five-yearly intervals. Although spatial patterns were metal-specific, in 2005 the lowest concentrations of metals in mosses were generally found in Scandinavia, the Baltic States and northern parts of the UK; the highest concentrations were generally found in Belgium and south-eastern Europe. The recent decline in emission and subsequent deposition of heavy metals across Europe has resulted in a decrease in the heavy metal concentration in mosses for the majority of metals. Since 1990, the concentration in mosses has declined the most for arsenic, cadmium, iron, lead and vanadium (52-72%), followed by copper, nickel and zinc (20-30%), with no significant reduction being observed for mercury (12% since 1995) and chromium (2%). However, temporal trends were country-specific with sometimes increases being found. 相似文献
606.
Rossella Guerrieri Rolf Siegwolf Francesco Ripullone Marco Borghetti 《Environmental pollution (Barking, Essex : 1987)》2010,158(9):2841-2847
We investigated the effect of N deposition (Ndep) on intrinsic water-use efficiency (WUEi), the ratio of photosynthesis (A) to stomatal conductance (gs), for two Quercus cerris stands at different distances to an oil refinery in Southern Italy. We used δ13C in tree rings for assessing changes in WUEi; while the influence of climate and NOx emission was explored through δ18O and δ15N, respectively. Differences in WUEi between the two sites were significant, with trees exposed to different degrees of NOx emissions showing an abrupt increase with the onset of pollution. Assuming similar gs at the two sites, as inferred through δ18O, the higher N availability at the polluted site caused the shift of the A/gs ratio in favour of A. Overall, our result suggests that an increase of Ndep may enhance tree WUE under a scenario of reduction of precipitation predicted for Mediterranean area. 相似文献
607.
J.N. Cape L.J. Sheppard A. Crossley N. van Dijk Y.S. Tang 《Environmental pollution (Barking, Essex : 1987)》2010,158(9):2926-2933
The content of organic N has been shown in many studies to increase during the passage of rain water through forest canopies. The source of this organic N is unknown, but generally assumed to come from canopy processing of wet or dry-deposited inorganic N. There have been very few experimental studies in the field to address the canopy formation or loss of organic N. We report two studies: a Scots pine canopy exposed to ammonia gas, and a Sitka spruce canopy exposed to ammonium and nitrate as wet deposition. In both cases, organic N deposition in throughfall was increased, but only represented a small fraction (<10%) of the additional inorganic N supplied, suggesting a limited capacity for net organic N production, similar in both conifer canopies under Scottish summertime conditions, of less than 1.6 mmol N m−2 mth−1 (equivalent to 3 kg N ha−1 y−1). 相似文献
608.
609.
610.
石油炼化企业烟气脱硫技术研究进展 总被引:1,自引:1,他引:0
石油炼化企业由于烟气特点、排放特征和减排设施的差别,导致了各炼化企业所采用的烟气脱硫技术的差别较大,尚无成熟、有效、经济的烟气脱硫技术,各炼化企业需要采用的二氧化硫减排技术差别也较大,选用适合炼化企业烟气脱硫的可行工艺技术具有重要现实意义。综合分析了目前国内外已工业化应用的主要烟气脱硫工艺、原理、技术的优缺点以及石油炼化企业烟气脱硫技术的发展趋势,为石油炼化企业烟气脱硫技术研究提供了借鉴和参考依据,并对石油炼化企业未来烟气脱硫技术的研究和选用提出了建议。 相似文献