Quantitative microbial risk assessment of bioaerosols in a wastewater treatment plant by using two aeration modes

Environmental Science and Pollution Research - Nonnegligible emission of bioaerosols usually occurs during aeration of wastewater in aerator tanks in wastewater treatment plants (WWTPs). Literature...     

Adsorption of volatile benzene series compounds by surface-modified glass fibers: kinetics,thermodynamic adsorption efficiencies,and mechanisms

Environmental Science and Pollution Research - The presence of volatile benzene series compounds (VBSCs) in the environment is continually increasing, with the potential for negative effects on...     

Analysis of the Effect of the Beavers‐Joseph Interface Condition on Flow in Karst Conduits1

Li, Guangquan, Yuan Cheng, and Bei Zhao, 2012. Analysis of the Effect of the Beavers‐Joseph Interface Condition on Flow in Karst Conduits. Journal of the American Water Resources Association (JAWRA) 1‐8. DOI: 10.1111/j.1752‐1688.2012.00683.x Abstract: In this study, we derive an approximate analytic solution for the distribution of flow velocity in a cylindrical conduit and the surrounding media, and analyze the effect of differing parameters (e.g., conduit radius) on the velocity of conduit flow. The solution is then employed to estimate the thickness of the boundary layer inside the media. The results reveal that when conduit radius is large, the Beavers‐Joseph condition has only a minor effect on the velocity of conduit flow (such that the nonslip condition on the conduit wall still works pretty well), and the boundary layer is so thin that the wall can still be treated as the interface between fast water in the conduit and slow water in the media. The solution indicates that the velocity of conduit flow is the superposition of the velocity profile in the nonslip situation onto the slip velocity on the wall. Our study theoretically shows that the coupled continuum pipe flow model in MODFLOW‐2005 constructed by the U.S. Geological Survey is reasonable in that there is no need to consider the Beavers‐Joseph condition when simulating flow in karst conduits. The role of the boundary layer in transport and its effect on the hyporheic zone is not clear, which is a suitable topic for future study.     

Influence of surface properties of RO membrane on membrane fouling for treating textile secondary effluent

Environmental Science and Pollution Research - Reverse osmosis (RO) is a promising technology for treating and reusing textile secondary effluent (SE). To better understand the effect of membrane...     

云南蒋家沟泥石流运动特征及其发展趋势

根据蒋家沟1965~2005年的泥石流运动观测资料与会泽气象站1965~2005年日降水资料,应用Hurst指数分析泥石流的运动要素,研究发现:泥石流年输沙量的Hurst指数为0.682时,年输沙量呈较强的正持续性,未来呈增长趋势;降雨量的Hurst指数0.605时,降雨量呈较弱的正持续性,未来呈较弱的增长趋势。同时,运用小波分析方法,发现泥石流输沙量具有多时间尺度周期的特征,主要表现为:第8、14和24年分别为其第1、2和3活动周期;结合小波方差图分析可知:在未来15 a以上,年输沙量将呈减少趋势,泥石流活跃程度弱;而15 a以内,未来将会保持较短时间的增加趋势,泥石流活跃程度强。综合以上分析可知:蒋家沟泥石流具有规模巨大,作用强烈,类型齐全等主要特征。     

淠河流域不同强度等级降水变化研究

淠河流域降水时空变率大,深入分析不同强度等级降水的特征和变化,对于全面揭示研究区气候变化、合理有效利用水资源、防治洪旱灾害具有十分重要的意义。基于淠河流域12个气象站1958~2012年逐日降水资料,分析年、季不同级别降水量(频次)的变化特点,以及主汛期(5~9月)连续3d最大降水量的概率分布。结果表明,淠河流域小雨量(频次)四季分布比较均匀,级别越高,降水频次越少,分布越集中,夏季暴雨多发。淠河流域年总降水量增加趋势不显著,总降水频次则显著减少。夏季各级别降水量(频次)均呈增加趋势,其中暴雨增加最显著,冬季总降水频次无明显趋势变化,小雨、中雨量增加显著,春、秋季总降水频次和小雨频次的减少趋势极其显著。淠河流域暴雨量、暴雨频次均在1968年发生增多突变,小雨频次在1975年有极显著减少突变,年总降水量有增多突变,总降水频次则有减少突变。自20世纪70年代后期以来,研究区主汛期连续3d极端强降水出现概率加大,不同重现期极值增大,洪涝灾害风险加剧。     

硫酸盐非均相机制对颗粒物污染的影响:上海典型污染事件的WRF-Chem模拟

硫酸盐气溶胶是大气中细颗粒物(PM_2.5)的重要组成部分,对霾的形成起着重要作用.传统的模式中硫酸盐生成机制主要包括SO₂与·OH的气相反应和SO₂·H₂O水合物产生的亚硫酸与O₃/H₂O₂的液相反应.SO₂非均相生成硫酸盐的机制（在高NH₃情景下,以NO₂为氧化剂,非均相摄取SO₂）非常重要,尤其成为重污染期间颗粒物浓度暴发性增长的原因之一.将硫酸盐非均相机制的参数化方案纳入WRF-Chem模式,模拟了2017年1月的长三角区域污染物浓度,评估了硫酸盐非均相反应对颗粒物浓度模拟的提高及其对长三角重污染的贡献.结果表明,传统WRF-Chem模式模拟的上海地区硫酸盐月均浓度为6.5μg·m^-3,较观测值低估33%;尤其是在重颗粒物污染期间,低估高达127%.加入硫酸盐非均相机制后,WRF-Chem对硫酸盐的模拟效果得到显著提升,...     

三峡库区稻田土壤重金属污染特征及风险评价

以三峡库区(重庆段)12个区县稻田土壤为研究对象,分析了土壤Cd、 Hg、 Pb、 As、 Cr、 Cu、 Zn和Ni含量,采用不同方法评估稻田土壤重金属的污染程度、潜在生态风险和人体健康风险.结果表明,三峡库区稻田土壤8种重金属除Cr外,其它7种重金属平均值均超过三峡库区土壤背景值,且分别有12.32%、 4.35%和2.54%的土壤样品Cd、 Cu和Ni含量超过相关标准的筛选值.8种重金属变异系数为29.08%～56.43%,属于中等及以上强度变异水平,受人为活动影响较大.8种重金属在土壤中均存在污染现象,且有16.30%、 6.52%和2.90%的土壤Cd、 Hg和Pb存在重度污染.同时,土壤Cd和Hg的潜在生态风险较高,整体为中度危害.12个区县中,巫溪县和巫山县污染程度较高,内梅罗综合污染评价为中等污染水平,且综合潜在生态风险也达到中度生态危害水平.健康风险评价结果表明,手口摄入是人体非致癌风险和致癌风险的主要暴露途径.土壤重金属对成人没有非致癌风险(HI<1),但有12.68%的点位对儿童具有非致癌风险(HI>1).土壤重金属对儿童具有致癌风险(TCR=5.75...