In situ removal of copper from sediments by a galvanic cell

This study dealt with in situ removal of copper from sediments through an electrokinetic (EK) process driven by a galvanic cell. Iron (Fe) and carbon (C) were placed separately and connected with a conductive wire. Polluted sediments were put between them and water was filled above the sediments. The galvanic cell was thus formed due to the different electrode potentials of Fe and C. The cell could remove the pollutants in the sediments by electromigration and/or electroosmosis. Results showed that a weak voltage less than 1V was formed by the galvanic cell. The voltage decreased with the increase of time. A slight increase of sediment pH from the anode (Fe) to the cathode (C) was observed. The presence of supernatant water inhibited the variation of sediment pH because H(+) and OH(-) could diffuse into the water. The removal of copper was affected by the sediment pH and the distribution of electrolyte in sediment and supernatant water. Lower pH led to higher removal efficiency. More electrolyte in the sediment and/or less electrolyte in the supernatant water favored the removal of copper. The major removal mechanism was proposed on the basis of the desorption of copper from sediment to pore solution and the subsequent electromigration of copper from the anode to the cathode. The diffusion of copper from sediment to supernatant water was negligible.     

尾气循环技术在国内顺酐装置的应用

顺酐生产过程排放的废气中含有大量未反应原料、副产物CO和挥发性有机物(VOC)等,对其进行处理使之达标排放,回收其中可利用的物质或能量有重要意义。吐哈石化厂顺酐装置采用CONSER公司工艺技术,新增部分尾气回收生产工艺路线,回收40%的尾气中的正丁烷,实现了蒸汽分阶利用,排放的废气中SO2、NOx、颗粒物等达到GB16297-1996《大气污染物综合排放标准》中二级标准。     

陕北子长县阎家沟黄土滑坡特征及其变形机制

野外调查和钻探资料显示,阎家沟滑坡属大型黄土滑坡,滑坡体为中、晚更新世黄土.在滑坡前缘流水侵蚀坡脚和滑坡体上修建窑洞、梯田、排放生活用水等人类工程活动影响下以及在2002年7月4日连续强降雨的激发下,目前处于不稳定状态,若遇强降雨失稳概率很大.填埋滑坡体裂隙和孔洞、加强地表排水、在滑坡体前缘沟谷修建淤地坝是提高陕北此类滑坡稳定性最为经济有效的措施.     

风险管理标准化述评

针对近年来三个重要的风险管理国际标准化文件:Guide 73:2002,澳大利亚的风险管理标准AS/NZS 4360:2004和ISO/CD 31000,以及国际减灾理事会的白皮书,评述了国际标准化文件在风险管理过程环节的基本条款和管理框架.Guide 73指引了风险管理领域最基础的术语,对全球的风险管理制定出通用的语言.它强调对于安全领域,风险管理把焦点放在危害的预防和减轻;AS/NZS 4360明确地确定了相关风险管理的定义,解释了风险管理的程序,重点强调要控制风险产生的后果;ISO/CD 31000聚合了大约26个国家的知识和经验,关注组织建立风险管理流程和不断地进行审评的重要性;IRGC强调群体感知是风险管理的前提,只有当群体认知到可能存在风险时,才会有利于用自己的判断经验去进行风险识别、划分和评价风险,进行风险评估.最后述评了中国风险管理标准化的工作以及在国际风险管理标准化中的贡献.     

探幽海螺沟

走过的地方不多,看过的地方不少,就自然风光而言,位于四川省甘孜藏族自治州泸定县境内的海螺沟冰川森林公园,是我见到过的最美的景致之一。然而,在全球升温和温室气体减排加剧的大背景下,海螺沟冰川雪线上升、冰川后退,形成了冰溜面、冰斗、冰川磨光面和冰川擦痕等特殊的冰蚀地貌,许多动植物资源正面临生死存亡的境地,一幕幕现实的场景呼唤着人类在享受现代化文明的同时,也要爱护和关心人类赖以生存的地球家园。     

Incorporating layer- and local-scale heterogeneities in numerical simulation of unsaturated flow and tracer transport

This study characterizes layer- and local-scale heterogeneities in hydraulic parameters (i.e., matrix permeability and porosity) and investigates the relative effect of layer- and local-scale heterogeneities on the uncertainty assessment of unsaturated flow and tracer transport in the unsaturated zone of Yucca Mountain, USA. The layer-scale heterogeneity is specific to hydrogeologic layers with layerwise properties, while the local-scale heterogeneity refers to the spatial variation of hydraulic properties within a layer. A Monte Carlo method is used to estimate mean, variance, and 5th, and 95th percentiles for the quantities of interest (e.g., matrix saturation and normalized cumulative mass arrival). Model simulations of unsaturated flow are evaluated by comparing the simulated and observed matrix saturations. Local-scale heterogeneity is examined by comparing the results of this study with those of the previous study that only considers layer-scale heterogeneity. We find that local-scale heterogeneity significantly increases predictive uncertainty in the percolation fluxes and tracer plumes, whereas the mean predictions are only slightly affected by the local-scale heterogeneity. The mean travel time of the conservative and reactive tracers to the water table in the early stage increases significantly due to the local-scale heterogeneity, while the influence of local-scale heterogeneity on travel time gradually decreases over time. Layer-scale heterogeneity is more important than local-scale heterogeneity for simulating overall tracer travel time, suggesting that it would be more cost-effective to reduce the layer-scale parameter uncertainty in order to reduce predictive uncertainty in tracer transport.     

张家口市中心城区饮用水安全的探讨

饮用水与人民群众的生活与健康休戚相关,因此保护饮用水水源地尤其重要。张家口市中心城区的饮用水水源地为地下水水源地,市区共有南北五个集中式供水水源地。近年来,由于农业污染、生活污染、个别企业超标排污以及上游来水不达标等原因,水源地水质下降。本文主要从5个水源地的水质、水量现状出发,探讨了影响水源地安全的因素,并提出相应的水源地保护措施：切实落实《饮用水水源地保护规划》、加强监管和立法以及提高公民环境意识。     

含磁粉生物反应器处理苯酚废水

采用含磁粉生物反应器对质量浓度为120～350 mg/L的苯酚模拟废水进行强化生物处理.实验结果表明:添加适量磁粉可使废水中DO提高约10%;与不含磁粉生物反应器比较,含磁粉生物反应器工艺使填料挂膜时间缩短1～2 d,填料上附着微生物量增多;质量浓度为350 mg/L的苯酚模拟废水在20 h内的苯酚去除率可达80%,降解时间缩短了10 h.初步分析了添加磁粉提高生物反应器处理废水效率的机理.实验证实了含磁粉生物反应器工艺的合理运用是强化处理含酚废水的有效途径.     

重金属吸附剂壳聚糖的改性研究进展

综述了重金属吸附剂壳聚糖改性研究的新进展,介绍了交联与接枝等改性方式对壳聚糖稳定性的影响及改性后的壳聚糖对水体中重金属离子吸附性能的改善.针对壳聚糖改性中仍然存在的一些问题,指出今后研究中值得关注的方向.     

混凝法深度处理印染废水中试研究

采用"高效混凝沉淀-过滤"深度处理工艺处理印染废水二级生化出水,并将混凝沉淀污泥回流.实验结果表明,混凝剂聚合氯化铝加入量为160 mg/L时,COD去除率平均可达34.6%,TP去除率平均达到87.9%,平均出水TP为0.3 mg/L.气相色谱-质谱分析和元素分析结果表明混凝沉淀工艺对有机物和TP的去除效果良好.