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991.
河流水环境中的非突发性水质风险模型研究 总被引:6,自引:0,他引:6
把影响水质模型的随机因素看成一个具有零均值的维纳过程,建立一个研究非突发性水质风险的随机微分动态模型,并对该维纳过程强度进行了估值。研究表明,水环境中的随机因素是引起非突发性风险的一个重要原因。 相似文献
992.
对混凝法处理铝件表面处理废水治理所得化学污泥再生利用进行了研究,得到了适宜的操作条件。结果表明,用浓硫酸溶解污泥的最佳用量为0.14~0.16mL/g湿污泥,湿污泥的溶解率可达90%,铝的溶出率也可达95%以上。把污泥的溶解液作混凝剂回用于印染废水的混凝处理也取得了良好的效果,其COD去除率≥80%,脱色率≥90%。实现了资源的二次利用,改善了作业环境,获得了较好的经济效益和社会效益。 相似文献
993.
复合表面活性剂对燃煤陶瓷窑炉黑烟润湿作用的研究 总被引:1,自引:0,他引:1
为了有效控制燃煤陶瓷窑炉黑烟的污染,根据理论和实验研究的结果,选择合适的润湿剂和助剂,研究了阴离子表面活性剂Y1、非离子表面活性剂F1与无机盐Z1复配后溶液表面张力的变化,筛选出了表面张力较小的配比。利用所选配比对燃煤陶瓷窑炉黑烟的润湿作用进行了Walker实验研究和理论分析。实验结果表明,0.5mmol/L Y1+50mmol/L Z1+0.03mmol/L F1的配比对黑烟的润湿作用较好。并对其润湿机理进行了探讨。 相似文献
994.
Modeling the aerobic metabolism of polyphosphate-accumulating organisms enriched with propionate as a carbon source. 总被引:1,自引:0,他引:1
Adrian Oehmen Raymond J Zeng Jürg Keller Zhiguo Yuan 《Water environment research》2007,79(13):2477-2486
In enhanced biological phosphorus removal (EBPR) systems, polyphosphate-accumulating organisms (PAOs) are primarily responsible for removing phosphate from wastewater. Propionate is an abundant carbon substrate in many EBPR plants and has been suggested to provide PAOs an advantage over their carbon competitors--the glycogen-accumulating organisms (GAOs). The aerobic metabolism of PAOs enriched with a propionate carbon source is studied in this paper. A metabolic model is proposed and experimentally validated to characterize the aerobic biochemical transformations by PAOs. The model predicts very well the experimental data obtained from the enriched PAO culture through solid-, liquid-, and gas-phase analyses. This model may be combined with previously formulated metabolic models to better describe the biochemical activity of PAOs with acetate and propionate as the primary carbon sources. Furthermore, it can also facilitate the study of the effect of different carbon sources on PAO-GAO competition. 相似文献
995.
Slurry-phase ozonation for remediation of sediments contaminated by polycyclic aromatic hydrocarbons
Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic, persistent, bioaccumulating organic compounds containing two or more fused aromatic rings. They are listed by the U.S. Environmental Protection Agency as priority pollutants because of their carcinogenicity and toxicity. Employing ozonation as a remediation technique, this work investigated the treatability of a sediment sample from a freshwater boat slip subjected to coal tar contamination over a long period. The contaminated sediment sample contained high levels of PAHs in the forms of naphthalene, phenanthrene, pyrene, and benzo[a]pyrene, among other byproducts present in the humic and solid phases of the sediment. The objectives of this work were to examine (1) the degradation of PAHs in the contaminated sediment as treated by ozonation in the slurry form, (2) the effects of ozonation upon the soil matrix and the biodegradability of the resultant PAH intermediates, and (3) the feasibility of a combined technique using O3 as a pretreatment followed by biological degradation. The sediment was made into 3% w/w soil slurries and ozonated in a 1.7-L semi-batch, well-stirred reactor equipped with pH control and a cold trap for the gaseous effluent. Samples were collected after different ozonation durations and tested for biochemical oxygen demand (BOD), chemical oxygen demand (COD), UV absorbance, and toxicity, along with quantitative and qualitative determinations of the parent and daughter intermediates using gas chromatography/flame ionization detection (GC/FID), GC/mass spectrometry (MS), and ion chromatography (IC) techniques. The GC/MS technique identified 16 compounds associated with the humic and solid phases of the sediment. Intermediates identified at different ozonation times suggested that the degradation of PAHs was initiated by an O3 attack resulting in ring cleavage, followed by the intermediates' oxidation reactions with O3 and the concomitant OH radical toward their mineralization. Results suggested that ozonation for 2 hr removed 50-100% of various PAHs in the solid and liquid phases (as well as the aqueous and gaseous media resulting from the treatment process) of the sediment sample and that organic and inorganic constituents of the sediment were also altered by ozonation. Measurements and comparisons of BOD, COD, UV absorbance, and toxicity of the samples further suggested that ozonation improved the bioavailability and biodegradability of the contaminants, despite the increased toxicity of the treatment effluent. An integrated chemical-biological system appeared to be feasible for treating recalcitrant compounds. 相似文献
996.
997.
本试验以盆栽方式,设置施不同形态的肥料共10个处理,以菜心为供试作物.测定土壤pH值、菜心产量、菜心植株的含镉量.试验结果表明:(1)10个处理对菜心的产量无显著影响;(2)土壤的pH值与植物的吸镉量呈负相关;土壤的pH值与所施肥料的形态有关,硝态氮肥可以减少植物的吸镉量,铵态氮肥也有一定的效果,硫酸铵则增加植物的吸镉量;磷肥、钾肥效果不显著,不同形态肥料之间的差异未达到显著水平;(3)有机复合肥对减少植物的吸镉量有一定的作用. 相似文献
998.
Zhengyong Xu Yang Zhaohui Zeng Guangming Xiao Yong Deng Jiuhua 《Frontiers of Environmental Science & Engineering》2007,1(1):43-48
The nitrogen removal mechanism was studied and analyzed when treating the ammonium-rich landfill leachate by a set of sequencing batch biofilm reactors (SBBRs), which was designed independently. At the liquid temperature of (32 ± 0.4)°C, and after a 58-days domestication period and a 33-days stabilization period, the efficiency of ammonium removal in the SBBR went up to 95%. Highly frequent intermittent aeration suppressed the activity of nitratebacteria, and also eliminated the influence on the activity of anaerobic ammonium oxidation (ANAMMOX) bacteria and nitritebacteria. This influence was caused by the accumulation of nitrous acid and the undulation of pH. During the aeration stage, the concentration of dissolved oxygen was controlled at 1.2–1.4 mg/L. The nitritebacteria became dominant and nitrite accumulated gradually. During the anoxic stage, along with the concentration debasement of the dissolved oxygen, ANAMMOX bacteria became dominant; then, the nitrite that was accumulated in the aeration stage was wiped off with ammonium simultaneously. 相似文献
999.
利用岩石类型资料1092个数据,肝癌死亡调查资料1544例,研究了肝癌死亡率与人群生存区的岩石类型(岩浆岩、变质岩、碳酸盐岩、碎屑岩、红色碎屑岩、第四系松散岩)的相关性。在此基础上,综合评价了与肝癌有相关性的岩石类型对肝癌的产生和发展的影响。 相似文献
1000.
大气污染、水资源污染、土壤污染三项因素,是造成环境水平逐年下降的主要原因。为全面结合绿色低碳会计理论,提升中国的综合环境质量,从大气污染、水资源污染、土壤污染三个角度,分析绿色低碳会计在环境污染治理中的应用情况。并从上述三个角度入手,分别对绿色低碳会计在环境污染治理中的影响,进行实证研究。根据研究结果,得出提升综合环境质量的具体方法;同时,研究绿色低碳会计对环境污染治理的影响,使中国整体环境状态,达到一个新标准。 相似文献