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841.
为了解西安市高新区采暖期大气颗粒物(包括PM1 0和PM2.5)污染状况,于2013年1月1日到2013年3月15日在高新区进行了为期74 d的连续自动采样。结果表明:采样期间高新区PM1 0的小时浓度范围28~1744μg/m3,平均浓度为332μg/m3;PM2.5的小时浓度范围13~946μg/m3,平均浓度为207μg/m3。PM2.5占PM1 0的平均比例为63.8%。颗粒物浓度日变化呈现弱双峰特征,分别在凌晨2:00和上午7:00~8:00左右达到浓度最高值,但是上午的峰值并不明显。颗粒物在15:00~1 6:00之间浓度达到最低值,由于受采暖影响,18:00之后颗粒物浓度明显上升。 相似文献
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843.
煤矸石是我国排放量最大的工业固体废物之一,其长期存放,不仅占用大量土地,而且还会污染大气、土壤和水体。本文介绍了我国煤矸石综合利用技术政策和控制目标,分析了我国煤矸石综合利用现状,在此基础上展望煤矸石综合利用的发展前景。 相似文献
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决策偏好对水环境污染物总量分配的影响 总被引:1,自引:0,他引:1
总量分配是制订污染物总量控制方案的基础,在总量分配方法中合理性指数法是由各因素组成的多目标分配方法,是一种新方法、新思路.由于各因素之间对应的权重系数通常采用专家打分方法确定,因此,分析主观性对总量分配结果的影响具有十分重要的意义.论文共选取30名不同领域的人员,并进行分组,分别对权重因子进行打分,分析不同类型的人员权重分布的特点及其对污染物总量分配结果的影响.研究结果表明:不同人员的权重因子对污染物总量分配具有一定的影响,对最后的决策结果产生一定的不确定性.从分配总量结果来看,TN、TP平均值分别为1.64万t·a-1、0.12万t·a-1,标准差分别为0.16万t·a-1、0.014万t·a-1,变差系数分别为0.09、0.12;从分组结果来看,管理人员一致性较好,研究人员一致性较差.总体而言,综合考虑不同领域专家的意见是保持总量分配方案的合理性和一致性的有效途径. 相似文献
848.
Two hybrid processes including ozonation-ceramic membrane-biological activated carbon (BAC) (Process A) and ceramic membrane-BAC (Process B) were compared to treat polluted raw water. The performance of hybrid processes was evaluated with the removal efficiencies of turbidity, ammonia and organic matter. The results indicated that more than 99% of particle count was removed by both hybrid processes and ozonation had no significant effect on its removal. BAC filtration greatly improved the removal of ammonia. Increasing the dissolved oxygen to 30.0 mg/L could lead to a removal of ammonia with concentrations as high as 7.80 mg/L and 8.69 mg/L for Processes A and B, respectively. The average removal efficiencies of total organic carbon and ultraviolet absorbance at 254 nm (UV254, a parameter indicating organic matter with aromatic structure) were 49% and 52% for Process A, 51% and 48% for Process B, respectively. Some organic matter was oxidized by ozone and this resulted in reduced membrane fouling and increased membrane flux by 25%-30%. However, pre-ozonation altered the components of the raw water and affected the microorganisms in the BAC, which may impact the removals of organic matter and nitrite negatively. 相似文献
849.
A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction(SR-Fenton) and visible light photocatalysis(Vis-Photo), for degradation of organic contaminants. The synergistic effect of SR-Fenton and Vis-Photo was observed through comparative tests of 50 mg/L Rhodamine B(Rh B) degradation and TOC removal. The Rhodamine B degradation rate and TOC removal were 100% and 68.1% using the SR-Fenton/Vis-Photo combined process under ambient conditions, respectively. Moreover, based on XRD, XPS and UV-DRS characterization, it can be deduced that tricobalt tetroxide located on the surface of the catalyst is the SR-Fenton active site, and cobalt ion implanted in the Ti O2 lattice is the reason for the visible light photocatalytic activity of Co–Ti O2. Finally, the effects of the calcination temperature and cobalt concentration on the synergistic performance were also investigated and a possible mechanism for the synergistic system was proposed. This coupled system exhibited excellent catalytic stability and reusability,and almost no dissolution of Co2+was found. 相似文献
850.
Bo Yao Lingxi Zhou Lingjun Xi Gen Zhang Lifeng Guo Zhao Liu Shuangxi Fang 《环境科学学报(英文版)》2014,26(12):2451-2458
We present in-situ measurements of atmospheric sulfur hexafluoride(SF6) conducted by an automated gas chromatograph–electron capture detector system and a gas chromatography/mass spectrometry system at a regional background site, Shangdianzi,in China, from June 2009 to May 2011, using the System for Observation of Greenhouse gases in Europe and Asia and Advanced Global Atmospheric Gases Experiment(AGAGE)techniques. The mean background and polluted mixing ratios for SF6 during the study period were 7.22 × 10-12(mol/mol, hereinafter) and 8.66 × 10-12, respectively. The averaged SF6 background mixing ratios at Shangdianzi were consistent with those obtained at other AGAGE stations located at similar latitudes(Trinidad Head and Mace Head), but larger than AGAGE stations in the Southern Hemisphere(Cape Grim and Cape Matatula). SF6 background mixing ratios increased rapidly during our study period, with a positive growth rate at 0.30 × 10-12year-1. The peak to peak amplitude of the seasonal cycle for SF6 background conditions was 0.07 × 10-12, while the seasonal fluctuation of polluted conditions was 2.16 × 10-12. During the study period, peak values of SF6 mixing ratios occurred in autumn when local surface horizontal winds originated from W/WSW/SW/SWS/S sectors, while lower levels of SF6 mixing ratios appeared as winds originated from N/NNE/NE/ENE/E sectors. 相似文献