生物法-人工湿地组合工艺对小城镇混合污水氮素去除效果研究

在华南热带亚热带地区,利用生物法-人工湿地组合工艺（A/BCO-CW）处理小城镇片区混合污水。全年运行结果表明,A/BCO-人工湿地组合系统对TN和NH4-N具有好的处理效果,年均去除率分别为57.57%、87.73%,平均去除负荷量达到3.85和3.26g·m-2·d-1。A/BCO预处理系统在停留时间为3～6h条件下,对NH4-N去除效率达57.38%,好氧段充分曝气,有利于硝化过程的进行,有效地解决人工湿地因溶解氧不足造成的硝化过程受限制情况,减少了后续湿地所需面积的25%。在0.30～0.59m·d-1水力负荷率下,垂直流-表面流-水平潜流人工湿地组合系统对TN和NH4-N平均去除负荷达到了2.56、0.90g·m-2·d-1;TN、NH4-N去除速率常数为39.8和41.62m·yr-1,这些数值均处于文献中k值范围的高量程内。在进水NH4-N变动范围为6.27～18.8mg·L-1时,出水水质均能稳定达到GB3838—2002《地表水环境质量标准》的IV类水1.5mg·L-1的标准。通过探讨A/BCO-CW组合工艺用于混合污水处理效率,实现了A/BCO和CW二者间在处理氮素过程中的优势互补。     

污水再生处理工艺中卡马西平的去除过程模拟及其生态风险评价

卡马西平在污水和水环境中广泛存在,且对水生生态系统安全构成风险,因此成为目前研究较多的药品之一。以北京清河再生水厂为例,研究"超滤—臭氧氧化—氯消毒"处理工艺中卡马西平的去除特性,并针对臭氧氧化和氯消毒工艺建立模拟卡马西平去除过程的机理模型。同时,利用美国环境保护署ECOTOX数据库,获取卡马西平对北京市水生生物物种的毒性数据,并基于毒性数据建立物种敏感度分布(species sensitivity distribution,SSD)模型,评价再生水厂出水补给地表水体时卡马西平产生的生态风险。臭氧氧化和氯消毒模型对卡马西平、总有机碳、氨氮等指标的模拟误差总体低于20%,模型的灵敏参数均可以被较好地识别,且其不确定性显著下降。对比7种SSD模型发现,对数正态分布和对数Logistic分布模型较好地拟合了北京市6个物种的卡马西平毒性数据,二者预测得到的总体生态风险期望值分别为7.4%和8.5%。     

几种有机废气吸收液对甲苯吸收效果的对比

采用自行设计的吸收装置,对比研究了国内外文献报道的几种有机废气吸收液(二乙基羟胺、聚乙二醇400、硅油、食用油、废机油、0#柴油)对模拟甲苯废气的吸收效果。结果表明,通过改变吸收液种类、废气中甲苯浓度等条件能够对甲苯废气吸收效果产生显著影响。随着吸收时间的延长,吸收液对甲苯的吸收率逐渐降低,直至达到动态饱和。随甲苯废气中甲苯浓度的增大,吸收液的有效吸收量减小,而饱和吸收量则增大。在相同实验条件下,二乙基羟胺对甲苯的有效吸收量与饱和吸收量均最大,其次是食用油、机油、0#柴油,而聚乙二醇与硅油吸收效果最差。本研究结果为合理选择甲苯废气的高效吸收液提供了理论依据。     

河流水质预测模型的应用研究

河流水质预测模型使用的参数未引入预测断面现状监测结果 ,使预测结果可能与现状监测结果发生矛盾。针对这一情况 ,通过对预测模式的推导转化 ,在模型中引入污染源现状源强和预测断面现状监测浓度 ,将预测结果同现状监测结果联系起来 ,使预测结果更贴近实际     

中国突发性环境污染事故应急监测研究

通过对近十多年(1994～2006)来我国有关突发性环境污染事故应急监测研究的文献进行统计、研读分析,文章得出我国突发性环境污染事故应急监测研究的进展:研究成果数量增加缓慢,质量提高较为明显;基础领域研究较为成熟,符合中国国情的应急监测程序体系初步形成,应急监测技术与方法较为先进,网络技术和GIS技术运用良好;应急监测立法体系落后,应急监测预案体系有待完善。     

环境空气中二氧化硫的自动监测及问题研究

介绍了空气中 SO2 的测定方法脉冲荧光法 ,对有关的问题进行了初步探讨。为正确使用该方法及仪器提供了依据。     

Organic micro-pollutant removal in liquid-phase using carbonized silk cotton hull

Phenolic compounds constitute one of the major pollutants in the modern world. Although many physical and chemical treatment technologies for their removal exist, most of them are economically not feasible. The present study was aimed at using silk cotton hull, a potent agricultural waste as an adsobent for removal of 2,4-dichlorophenol (2,4-DCP), which was used as a model phenolic compound. The process parameters were investigated and optimized conditions were determined. The equilibrium time was found to ...     

Safety parameters for oxygen-enriched flames

The utilization of low-quality gaseous fuel from biomass gasification and the abundance of oxygen-rich streams obtained as a by-product of nitrogen-air separation by membrane technology has incentivized the development of sustainable oxygen-enriched combustion technologies in the last decades. However, a dearth of experimental and numerical analysis addressing the reactivity and safety aspects of these mixtures at initial low temperatures can be observed in the current literature.In this work, the heat flux burner was adopted for the measurement of the laminar burning velocity of methane in oxygen enriched air at different equivalence ratios. Results were compared with numerical data obtained by means of detailed kinetic mechanisms developed at the University of Bologna and the Gas Research Institute (GriMech3.0). Simplified correlations for the estimation of the laminar burning velocity with respect to the oxygen content at any equivalence ratio were developed, tested and evaluated.An elemental reaction-based function was found appropriate for the estimation of the overall reactivity of the investigated mixtures. Besides, numerical analyses were performed to characterize the flame structures in terms of temperature and product distribution under several initial conditions. These results gave further insights into the reaction mechanisms of gaseous fuels in the case of oxygen-enriched air, highlighting potential bottlenecks for kinetic model refinements. Eventually, relevant safety parameters were estimated, in particular the flammability range of the fuel/oxidant mixture, in terms of lower and upper flammability limits.     

Influence of water storage on deflagration characteristics of methane in confined space

Comparative experiments were conducted under different water level heights and methane concentration conditions using a self-designed explosion experiment pipeline. The results showed that, in comparison with the scenario without water storage, when the water level was 2 cm and methane concentration was 6.5–12.5%, there was a dual effect including a pressure decrease caused by the endothermic cooling of liquid water and a pressure increase caused by the expansion of water vapour. These effects caused the pressure time history curve to exhibit a double-peak or multi-peak structure, and the average decrease in the peak deflagration pressure was 23.76%. The heat of vaporisation absorbed by the stored water and barrier effect of water vapour on the transfer of the heat slowed down the increase in the deflagration temperature. The average decrease in the peak deflagration temperature of methane was 13.82%, and the time to reach the peak deflagration temperature was extended as a whole, with an average delay of 0.22 s. Water storage also changed the shape of the deflagration flame front, which exhibited ‘knife’, ‘V’, and ‘crescent’ structures. Moreover, the flame propagation speed was significantly reduced, with the peak and average flame propagation speeds decreased by 83.3% and 83.6%, respectively. The research results can provide a certain reference for preventing gas explosions in typical confined spaces, and also help to explore new anti-explosion methods, which can be applied to marine equipment such as ships.     

中国地震应急二级分区的初步研究

在已有地震应急宏观分区研究的基础上,首先讨论了进一步开展地震应急次级分区的意义及其分区方案的多样性;然后提取“政治经济强辐射中心、少数民族聚居区、贫困人口聚居区、侨乡、大型工业危险源”等5方面社会经济因素在不同县域内的10种主要组合类型作为区划指标,采取“自下而上归并”的区划途径,进行了中国地震应急二级分区研究。结果表明,在将我国大陆划分为8个地震应急一级大区的基础上,从社会经济角度又可大致划分出19个二级区;二级区的划分进一步揭示了不同地区开展地震应急工作时应注意的一些较具体的社会经济问题及其空间配置特点;两级分区的结合从“宏观概括”和“中观具体”两个层次示范了地震应急分区研究的基本内容。