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1.
城市污水处理厂污泥沉降影响因素研究   总被引:4,自引:0,他引:4  
研究总结了目前城市污水处理厂污泥沉降影响的因素,概括总结了pH值、溶解氧、温度、盐度等环境因素以及磁场等外部环境因素对不同性状污泥的沉降影响。为污泥沉降脱水最佳条件提供了研究思路,也为污泥后续机械脱水提供了基础。  相似文献   
2.
铁尾矿地砖的制备及其机理分析   总被引:2,自引:0,他引:2  
简要介绍了唐山地区铁矿尾矿制备铁尾矿砖的试验研究,并设计制备铁尾矿砖生产工艺流程和最佳配比。研究结果表明,以铁尾矿为主要材料,通过掺加适量的水泥、粉煤灰、粗骨料和一定的外加剂,经常温常压养护28天后,抗压强度可达到28.30MPa,抗折强度为5.63MPa,同时长期性能研究也表明可以制备出合格的铁尾矿地砖。为铁尾矿大量资源化利用辊供了一条新的徐径.同时还对铁尾砖的微观机理作了初步研究。  相似文献   
3.
根据全省自然环境和社会环境结构特征、分异规律、所存在的主要环境问题,依据区内相似性与区间差异性的基本原则,进行了三个层次的三级环境区划。研究各环境区的环境结构、环境特征与环境灾害、环境污染等问题之间的内在联系;揭示生态环境失调与人类生产活动之间的相互关系;探讨各环境区经济发展的环境负荷以及今后发展方向与途径;提出各环境区主要环境问题及其相应的防治、管理对策。  相似文献   
4.
为了识别恶臭污染源排放特征以及了解不同行业恶臭物质排放差异,对恶臭污染排放源指纹谱指标物质进行了筛选,并依据筛选结果对6家典型恶臭排放企业进行样品采集及分析,绘制了各家企业的指纹谱图.结果表明:①通过物质嗅觉阈值与AMGE(ambient multimedia environmental goals,周围环境目标值)和RfC(reference concentration,健康风险参考浓度)对比以及结合国内外恶臭标准受控物质和现有的标准检测方法,最终确定了包括三甲胺、硫化氢、甲硫醇等典型恶臭物质在内的19种物质作为指纹谱指标物质.②依据我国现行的标准监测分析方法对19种恶臭指标物进行检测,初步得到了各家企业的恶臭物质指纹谱数据,绘制了各家企业的指纹谱图.③指纹谱成分分析结果显示,污水处理厂主要的恶臭物质是硫化氢,ρ(硫化氢)为44.566 mg/m3;涂料企业ρ(甲基乙基酮)、ρ(丁醛)和ρ(乙酸乙酯)较高,分别为39.037、28.757、27.840 mg/m3;制药企业ρ(丙醛)较高,为4.791 mg/m3;汽车和家具制造企业ρ(二甲苯)较高,分别为15.209和2.081 mg/m3.④应用分歧系数法分析不同企业指纹谱之间的相似程度,分析结果显示,分歧系数在0.331~0.809之间,不同企业之间指纹谱存在较大差异.研究显示,建立恶臭污染排放源指纹谱可进行恶臭源排放特征识别,为恶臭污染溯源提供基础数据和科学依据.   相似文献   
5.
Atmospheric peroxyacetyl nitrate(PAN), peroxypropionyl nitrate(PPN), and carbon tetrachloride(CCl4) were measured from September 2010 to August 2011 in Beijing. PAN exhibited low values from mid-autumn to early spring(October to March) with monthly average concentrations ranging from 0.28 to 0.73 ppbV, and increased from early spring to summer(March to August), ranging from 1.37–3.79 ppbV. The monthly variation of PPN was similar to PAN, with low values(below detection limit to 0.18 ppbV) from mid-autumn to early spring, and a monthly maximum in September(1.14 ppbV). The monthly variation of CCl4was tightly related to the variation of temperature, exhibiting a minimum in winter(69.3 pptV) and a maximum of 180.6 pptV in summer. Due to weak solar intensity and short duration, PAN and O3showed no distinct diurnal patterns from morning to night during winter, whereas for other seasons, they both exhibited maximal values in the late afternoon(ca. 15:00 to 16:00 local time) and minimal values during early morning and midnight. Good linear correlations between PAN and PPN were found in autumn(R = 0.91), spring(R = 0.94), and summer(R = 0.81), with slopes of 0.130, 0.222, and 0.133, respectively, suggesting that anthropogenic hydrocarbons dominated the photochemical formation of PANs in Beijing. Positive correlation between PAN and O3 in summer with the low slopes( O3 / PAN) ranging from 9.92 to 18.0 indicated serious air pollution in Beijing, and strong negative correlation in winter reflected strong O3consumption by NO titration and less thermal decompositin of PAN.  相似文献   
6.
This study investigated the soil nematode community structure along the Yellow River in the Lanzhou area of China, and analyzed the impact of heavy metals (Cd, Pb, Cr, Cu, and Zn) and polycyclic aromatic hydrocarbons (PAHs) on the nematode community. Soil samples from five locations (named A–E), which were chosen for soil analysis, showed significant differences in their heavy metal content (p < 0.01), as well as in the variety of nematodes (up to 41 genera) and families (up to 20) that were present. The different samples also differed significantly in the total PAH content (p < 0.05), as well as the six types of PAH present. Sites A–C showed the most severe contamination with heavy metals and PAHs; these sites had the lowest abundance of fungivores and omnivore/predators, but the proportion of bacteriovores was the highest (p < 0.05). Site E, in contrast, showed only minor pollution with heavy metals and PAHs, and it contained the highest abundance of plant parasites (p < 0.05). Several nematode ecological indicators were found to correlate with concentration of soil pollutants at all the sites tested: the maturity index (MI, in addition to plant parasites), plant parasite index (PPI), ΣMI (including all the soil nematodes), Shannon-Wiener diversity index (H′′), and Wasilewska index (WI). Disturbance to the soil environment was more severe when MI, ΣMI, and H′ values were lower. The results of the study show that the abundance and structure of the soil nematode communities in the sampling locations were strongly influenced by levels of heavy metals and PAHs in the soil. They also show that the diversity index H′ and the maturity index can be valuable tools for assessing the impact of pollutants on nematodes.  相似文献   
7.
8.
Atmospheric BTEX compounds(benzene, toluene, ethylbenzene and xylenes) in a rural site of the North China Plain(NCP) were preliminarily investigated in winter, and the outdoor concentrations(25.8–236.0 μg/m3) were found to be much higher than those reported in urban regions. The pollution of BTEX inside a farmer's house was even more serious, with combined concentrations of 254.5–1552.9 μg/m3. Based on the ratio of benzene to toluene(1.17 ± 0.34) measured, the serious BTEX pollution in the rural site was mainly ascribed to domestic coal combustion for heating during the winter season. With the enhancement of farmers' incomes in recent years, coal consumption by farmers in the NCP is rapidly increasing to keep their houses warm, and hence the serious air pollution in rural areas of the NCP during winter, including BTEX, should be paid great attention.  相似文献   
9.
随着中国加入WTO和西部大开发战略的实施 ,依法治国无疑是改善投资环境、促进西部开发的最有效手段之一。本文根据WTO基本原则与法制经济的相互关系和影响深入浅出地论述了WTO对西部开发的影响、风险及机遇 ,并提出了针对性的策略  相似文献   
10.
分析认为输油管道的最大腐蚀深度符合Ⅰ型极大值分布,基于许用可靠度,建立了2个计算公式:①确定输油管道的腐蚀裕量;②确定输油管道的腐蚀剩余寿命.实例验证了方法的有效合理性.  相似文献   
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