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211.
广州城市生态环境变化 总被引:5,自引:0,他引:5
对广州城市生态环境因子的大气,水,固体废弃物和噪声污染状况近十年数据结合广州城市发展,分析其环境污染变化特征,结果表明,广州市大气环境污染已由煤烟型向石油型转变;环境中有机污染严重,主要表现为氨氮,BOD5,砷化物和汞化物污染,固体垃圾产出量逐年增加,声环境在逐步好转。 相似文献
212.
沈阳市区大气颗粒物元素组分及其分布 总被引:3,自引:1,他引:3
本研究采用美国安德逊五段冲击式采样器进行大气颗粒物采样,用中子活化法进行分析,获得43种元素质量浓度,并求得各种元素的质量中值直径和几何标准差。 相似文献
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Ren Shufen Zhang Xuelin Li Wencheng Wang Wensheng Wang Jin Wang Wenjun Zhang Yuxia 《环境科学学报(英文版)》1991,3(4):95-101
The humic acid contents in drinking water and soil in Kaschin-Beck disease areas were found more than that of non-disease areas in this research. Changes of free radical concentration in drinking water were agreed with that of humic acid contents in drinking water of Kaschin-Beck disease areas. A positive correlation of free radical concentration and humic acid content in drinking water has been shown (r=0.913) . The structure of I. R. spectra of humic acid under ultraviolet light has been changed. Thus it indicated that free radical was resulted from benzoqiunonyl groups of humic acid in environment. 相似文献
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Reducing bioassay variability by identifying sources of variation and controlling important parameters in assay protocol was demonstrated in this study. The variability of a bioassay based on a luminescent bacterium was examined as an example. This assay involved the growth of cells, storage at a low temperature, activation, and exposure to a test sample, and the assay response was bioluminescence inhibition. After determining that measurement error was small and negligible, the total assay variability was decomposed in an initial variance components study into between-batch, between-vial, and between-tube variations. Results indicated that between-vial variations accounted for the majority of the total observed variability and that reducing this type of variation would be beneficial. Five parameters in the assay protocol were determined as factors that potentially affected assay variability significantly. A split-plot design was employed to investigate the effects of these factors and some of their interactions on the assay response. One of the five factors, i.e., activation temperature, turned out to have a significant effect. The variance components study was repeated with better control of activation temperature as well as other parameters. Results indicated that the total variability of the bioassay was reduced by approximately 85%. 相似文献
217.
湿热法处理实现厨余垃圾饲料化的研究 总被引:9,自引:0,他引:9
探索了湿热法工艺处理厨余垃圾并将其饲料化的可行性.实验表明,湿热法处理可以在满足消毒杀菌的同时,降低厨余原料中的高油脂含量和高含盐量,调节营养成分,实现物化性状的均一.经湿热法处理后的厨余垃圾的饲用价值得到明显改善,可作为良好的饲料原料,同时可回收利用油脂.总之,湿热法工艺可实现厨余垃圾的无害化、减量化和资源化处理,对于消除环境污染、缓解我国饲料原料紧张及资源回收利用等方面有着显著的环境效益、社会效益和经济效益,具有重要的现实意义. 相似文献
218.
Effect of pH on phosphine production and the fate of phosphorus during anaerobic process with granular sludge 总被引:6,自引:0,他引:6
The effect of pH on phosphine formation during anaerobic cultivation of granular sludge was investigated. The sludge was taken from full-scale anaerobic reactors treating brewery wastewater. Acetate and phosphate were used as the carbon source and phosphorus source respectively. After 10 days cultivation in the dark, results showed that acidic conditions were more favorable for free phosphine production. At pH 5, the optimum concentration 86.42 ng PH3 m-3 of free phosphine was obtained. The level at pH 7 was reduced to 18.53 ng PH3 m-3, about 1/5 of the maximum. The maximum concentration of matrix-bound phosphine of 3.30 ng PH3 kg-1 wet sludge was achieved at pH 6. More than 83% of the total phosphine was matrix-bound phosphine, which accounted for 0.003-0.009 per thousand of the phosphate removal, while free phosphine comprised 0.00002-0.001 per thousand of the phosphate removal. Most of the phosphorus removal from solution was turned into chemical precipitation or was adsorbed by sludge. The mechanism of the phosphate reduction-step in the formation of phosphine production is still unknown. The promotion of phosphine formation by low pH is compatible with an acidic bio-corrosion mechanism of metal particles in the sludge or of metal phosphides which form phosphine at low pH. 相似文献
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220.
Zhu J Cao XL Pigeon R Mitchell K 《Journal of the Air & Waste Management Association (1995)》2003,53(1):67-76
Three diesel fuels, one oil sand-derived (OSD) diesel serving as base fuel, one cetane-enhanced base fuel, and one oxygenate [diethylene glycol dimethyl ether (DEDM)]-blended base fuel, were tested for their emission characterizations in vehicle exhaust on a light-duty diesel truck that reflects the engine technology of the 1994 North American standard. Both the cetane-enhanced and the oxygenate-blended fuels were able to reduce regulated [CO, particulate matter (PM), total hydrocarbon (THC)] and nonregulated [polyaromatic hydrocarbons (PAHs), carbonyls, and other volatile organic chemicals] emissions, except for nitrogen oxides (NO(x)), compared with the base fuel. Although burning a fuel that contains oxygen could conceivably yield more oxygenated compounds in emissions, the oxygenate-blended diesel fuel resulted in reduced emissions of formaldehyde along with hydrocarbons such as benzene, 1,3-butadiene, and PAHs. Reductions in nitro-PAH emissions have been observed in both the cetane-enhanced and oxygenated fuels. This further demonstrates the benefits of using a cetane enhancer and the oxygenated fuel component. 相似文献