生活垃圾焚烧飞灰重金属在浸出柱中的浸出规律

通过浸出柱实验,研究生活垃圾焚烧飞灰中重金属的动态浸出规律.结果表明,浸出液中各种重金属的质量浓度均随浸取剂与飞灰比值(L/S)增大而减小,并在L/S＞2后趋于稳定.除Pb外,浸出质量浓度均低于污水综合排放标准(GB 8978-1996)限值.对比原灰与浸出残留物重金属多级提取结果表明,飞灰的重金属在浸出柱实验中释放能力由强到弱依次为:Cd、Ni、Cu、Pb、Zn和Cr.受浸取剂pH值和固液接触方式影响,浸出柱重金属累计浸出量都小于国家标准(GB 5086.2-1997)浸出量(Cd除外),尤其Cr、Hg和Pb的浸出柱累计浸出量分别是国标浸出量的23.25%、1.29%和14.29%     

Biosorption of Cu(II) and Zn(II) onto a lignocellulosic substrate extracted from wheat bran

We studied the removal of copper and zinc ions from aqueous solutions using a lignocellulosic substrate obtained by an acido-basic treatment of wheat bran. The sorption capacity of this material was investigated through batch and column experiments. Batch experimental results showed that the retention capacity of the lignocellulosic substrate was 0.20×10^–3 mol g^–1 at pH 4.5 for copper(II) and 0.24×10^–3 mol g^–1 at pH 6.5 for zinc(II). Column experiments showed a reduced sorption capacity for both ions compared to batch experiments. Batch and column data were analysed using the Langmuir equation in order to determine the affinity constant and the binding capacity of the sorbent and to compare both retention processes.     

DESALTING SALINE WATER FOR IRRIGATION A CASE STUDY,COACHELLA AREA,CALIFORNIA1

ABSTRACT .A case study was performed to evaluate potential applications of desalted saline water for agriculture using 2 distillation type processes and 2 membrane type processes. The investigation determined the costs and benefits associated with desalting saline water at concentrations of 1,500, 900, 400, 200, and 50 ppm. Benefits from desalting are generated by shifts to more profitable crops, reduced costs for drainage, and reduction in fertilizer and labor requirements with better quality water. Costs are based on the project features such as desalting plants, raw water diversion facilities, storage reservoirs, conveyance and distribution systems, brine disposal, blending facilities, and gypsum addition systems. Hydrologic studies determined the crop irrigation requirements, water demand schedules, desalted water storage requirements, brine disposal requirements, and size of facilities required. Reconnaissance design layouts were made for producing desalted water using a combination of 14 schemes. The study also included a review of irrigation practices. The benefit-cost ratios range from 0.4 to 1.0 for 1,500 ppm irrigation water to 0.8 to 1.0 for 50 and 200 ppm water. Investment costs per acre are high, ranging from $12,900 to $20,900. Irrigation benefits are based on the increase in production from a desert condition with no water supply to the irrigation conditions studied.     

川东平行岭谷区自然景观垂直分异规律及综合分区--以重庆北碚区为例

以重庆市北碚区为代表,论述了川东平行岭谷区自然景观的垂直分异特征,并在此基础上对该区域进行了综合分区,再结合各分区内土地的自然特征采取不同的措施,从而做到因地制宜地发展各项生产.     

Heterogeneous Traffic Induced Effects on Vertical Dispersion Parameter in the Near Field of Roadways - a Wind Tunnel Study

The varying traffic parameters such as traffic volume, speed, shape and size, and terrain roughness conditions play a vital role on dispersion of pollutants in the near field of roadways. Simulation experiments were carried out in the Environmental Wind Tunnel (EWT) to evaluate the traffic induced effects on vertical dispersion parameter (σ _z ) for heterogeneous traffic conditions in the near field of roadways for evaluating the effect of variations in traffic volume, terrain roughness condition and approaching wind direction. The model vehicle movement system was fabricated and made operational in the EWT, which allowed the variation in traffic volume, speed and wind road inclination. Sixty-six hydrocarbon tracer experiments were performed to evaluate σ _z in the near field of roadways for variable traffic volume, three terrain roughness conditions and two approaching wind directions (i.e., 90° and 60°). The values of σ _z for heterogeneous traffic conditions were found to be higher for low roughness conditions in comparison to other two higher roughness conditions for various traffic volumes and approaching wind directions. This revised version was published online in July 2006 with corrections to the Cover Date.     

钢轨接头轨缝值和行车速度对轮轨垂向振动的影响

为了分析轨缝值与行车速度对车辆通过钢轨接头时产生的振动与噪声的影响程度,利用有限元方法,建立了车辆—轨道垂向耦合动力计算模型;该模型的车辆采用整车模型,共10个自由度;轨道结构采用3层弹性点支承有限长欧拉梁模型,共402个自由度;系统的激励大小可由轨缝值和行车速度推导出来,并运用赫兹非线性接触理论计算轮轨之间的相互作用力。采用该模型,结合快速显式迭代积分法和MATLAB6.5强大的矩阵分析功能,对不同轨缝值和车辆行驶速度条件下钢轨接头的动力响应进行了计算,为减振降噪提供理论依据。     

Vertical distributions of COS and CS2 in Beijing City

Vertical distributions of COS and CS2 were measured at a meteorological tower in Beijing City. The mixing ratios of COS and CS2 are in the range of 371--1681 pptv and 246--1222 pptv, respectively. The significant high mixing ratios of the two compounds at ground level and distinct vertical distributions indicated the existence of strong anthropogenic sources of COS and CS2 in Beijing City. Domestic stoves and central heaters are important sources of COS during winter season. Cesspools may play significant role on COS over whole seasons. Chemical productions may be responsible for the observed hiah mixina ratios of CS2 in Beiiina Citv.     

点源激振下地表竖向位移的近-远场分界线

在竖向点源作用下 ,地基表面的竖向振动随着源距的增大而衰减 ;但因在近振源区域受体波 (P波、S波 )影响大而在较远处受表面波 (R波 )控制 ,近、远场地表振动的定量衰减规律存在着较大的差异 ,可靠地确定近—远场的分界线便具有重要的学术和应用价值。本文在综述既有研究成果的基础上 ,通过比较Lamb问题的精确解和瑞利近似解 ,较为系统地对这一问题进行了分析 ,结果表明 :由地表竖向位移振幅确定的近—远场分界线较由其相位确定的为远 ,前者源距将随地基泊松比的升高和容许误差的减小而增大且目前的常见取值明显偏小 ,后者与地基泊松比的变化几乎无关。之所以分界线源距随地基泊松比升高而增大 ,主要是由于此时的P波波长增大的影响比S波和R波波长增大的影响要大而造成的。     

陶粒复合垂直流人工湿地对污水季节性处理效果的试验研究

研究了四种陶粒组合、一种石灰石碎石5套复合垂直流人工湿地在不同季节处理生活污水的运行效果。结果表明:陶粒组合人工湿地系统对COD、TP、NH3-N的去除效果均优于石灰石碎石湿地;复合垂直流人工湿地对COD的去除效果在冬季有所下降,但仍保持在50%以上;湿地系统对TP去除率受季节性变化影响不显著,但随着复合垂直流人工湿地系统的运行,基质层对TP的吸附逐渐饱和,去除效率缓慢下降;1号~5号人工湿地对氨氮的去除率分别从秋季42.0%、55.1%、61.1%、49.9%、50.2%下降至冬季21.9%、31.0%、36.5%、28.5%、29.2%,春、夏季处理效率开始回升,并保持稳定的状态。     

水中Mg 2+ 的测试管快速测定

研制了一种测定水中Mg^2 的测试管，测定范围为0.5mg/L-2.0mg/L，该测试管适用于现场应急监测，具有快速、简便、抗干扰能力强和价格低廉等特点。