傍河型水源井氨氮阻断与去除工程设计案例分析

针对沈阳市傍河型水源地的氨氮(NH+4-N)污染问题,通过野外研究区的水文地质调查,在查明研究区NH+4-N污染特征的基础上,结合室内批试验、柱实验和数值模拟,筛选出最佳的NH+4-N去除方案,提出了研究区渗透反应格栅(PRB)构建方案,并成功构建了示范工程尺度的PRB,用以去除地下水中的NH+4-N污染.室内批实验和柱实验表明,利用微生物硝化作用结合沸石的吸附作用去除地下水中NH+4-N是可行的.通过对研究区水质数值模拟,发现构建有一定弧度的PRB能最大限度的保护水源井.在PRB的构建过程中,利用高压旋喷技术和旋挖技术解决了大深度(30 m)PRB的构建问题,且PRB建成运行监测表明,示范工程尺度的PRB能有效阻断和去除地下水中NH+4-N.     

Experimental studies of removing typical VOCs by dielectric barrier discharge reactor of different sizes

This research conducted both lab-scale and pilot-scale tests by selecting toluene as the typical volatile organic compounds (VOCs) and by using the promising non-thermal plasma oxidation technology – dielectric barrier discharge (DBD). To develop baseline engineering data to demonstrate the feasibility of application of self-made DBD reactors, the peak voltage, gas flow speed, initial toluene concentration, discharge frequency and duty ratio were studied. The results showed that toluene removal efficiency improves with increase of electrical voltage, frequency and duty ratio, and declines with increase of polar distance, gas flow speed and toluene initial concentration. When the voltage increases, the energy efficiency rises first and then drops. The energy efficiency reaches the climax when the energy density reaches 150.8 J/L and 101.7 J/L in the lab-scale experiment and pilot-scale experiment respectively.     

Quantification of changes in zero valent iron morphology using X-ray computed tomography

Morphological changes within the porous architecture of laboratory scale zero valent iron （ZVI） permeable reactive barriers （PRBs）, after exposure to different groundwater conditions, have been quantified experimentally for different ZVI/sand ratios （10%, 50% and 100%, W/W） with the aim of inferring porosity changes in field barriers. Column studies were conducted to simulate interaction with different water chemistries, a synthetic groundwater, acidic drainage and deionised （DI） water as control. Morphological changes, in terms of pore size and distribution, were measured using X-ray computed tomography （CT）. CT image analysis revealed significant morphological changes in columns treated with different water chemistries. For example, 100% ZVI （W/W） columns had a higher frequency of small pores （0.6 mm） was observed in ZVI grains reacted with typical groundwater, resulting in a porosity of 27%, compared to 32% when exposed to DI water. In comparison, ZVI grains treated with the acidic drainage had higher porosity （44%） and larger average pore size （2.8 mm）. 10% ZVI PRB barrier material had the highest mean porosity （56%） after exposure to any water chemistry whilst 100% ZVI （W/W） columns always had the lowest （34%） with the 50% ZVI （W/W） in between （40%）. These results agree with previously published PRB field data and simultaneously conducted geochemical monitoring and mass balance calculation, indicating that both the geochemical and hydraulic environment of the PRB play an important role in determining barrier lifespan. This study suggests that X-ray CT image analysis is a powerful tool for studying the detailed inter pores between ZVI grains within PRBs.     

钚在某处置工程屏障水环境中化学形态及影响因素

针对某放射性废物包装容器回填处置工程屏障结构特征,采用岩体裂隙水浸泡工程屏障样品的方式,在对各平衡水样化学成分分析的基础上,利用地球化学模拟软件EQ3/6对钚在回填工程屏障水环境中的存在化学形态进行了模拟计算,得出钚在回填工程屏障水环境中主要以Pu(Ⅳ)价态Pu(OH)5-形式存在,同时水环境中pH值和Eh值的变化皆会影响钚的存在化学形态和价态。     

郴州市王仙岭尾砂库重金属污染治理工程实例

介绍了湖南省郴州市王仙岭旅游度假区尾砂重金属污染治理工程,包括该场地重金属污染的现状调查与分析,修复技术的分析和选用以及实施工艺。为防止尾砂污染扩散,该工程主要采用重金属稳定化和阻隔防渗组合技术。该工程的成功实施证明其所采用的调查方法、工程技术和施工工艺的有效性,可为同类项目的调查、设计与施工提供参考借鉴。     

国内道路声屏障行业发展中的几个问题浅析

随着国内交通的发展,铁路、公路、桥梁、地铁、轻轨、高架路越来越多,车速越来越快,人们在享受便捷交通的同时也越来越受到交通噪声的困扰,声屏障作为交通噪声治理的主要手段,已得到大规模使用,本文根据作者个人的经验和体会,总结了行业的现状和存在的问题,得出门槛低、预算低、标准落后是目前阻碍声屏障行业发展和水平提高的关键。     

介质阻挡放电降解异味物质CS_2研究

采用介质阻挡放电降解二硫化碳(CS2)模拟废气,考察了外加气体空气、氮气(N2)、电源输入功率、初始浓度和停留时间对CS2转化率的影响。结果表明:CS2的去除率呈现空气>N2。在输入功率63 W,停留时间为5.34 s,CS2的初始浓度300 mg/m3,N2氛围下的去除效率为36.9%,而空气氛围下的去除效率可达62.5%。在N2与空气氛围下其产物明显不同,在空气氛围下,主要产物为SO2、COS、CO和CO2;而在N2氛围下其主要产物为大量单质硫、少量CO与CO2。对DBD降解CS2的机理分析表明,在N2条件下主要是高能电子与紫外光的作用;而在有空气条件下,O2的存在促进了CS2的深度氧化。     

针-板式介质阻挡放电降解土壤中对硝基苯酚研究

采用针-板式介质阻挡放电(DBD)产生低温等离子体降解土壤中对硝基苯酚(PNP),考察了放电电压、载气气量、土壤含水率以及土壤pH值对土壤中PNP降解效果的影响。结果表明:针-板式DBD对土壤中PNP有良好的降解效果。在PNP初始浓度400mg/kg,放电电压18 kV条件下,放电处理60 min,PNP降解率达到87.3%。增加放电电压和含水率均能提高降解率。不通入载气,也有较好的降解效果。碱性条件有利于PNP降解。     

基于直觉模糊距离法的堰塞湖减灾方案选优

针对堰塞湖减灾群决策信息的不确定性与模糊性,为解决不完全信息条件下属性指标及专家之间存在的相互关联群决策问题,综合运用直觉模糊集理论、海明距离原理和熵权理论,将直觉模糊距离群决策方法运用到堰塞湖减灾决策过程中。工程实例研究表明,运用直觉模糊距离法决策出的最优方案具有较高的区分度和敏感性,增强了决策的客观性、科学性,能为堰塞湖减灾决策提供更为可靠的依据,具有较强的实用价值。     

Process-based reactive transport modeling of a permeable reactive barrier for the treatment of mine drainage

Reactive transport modeling of a permeable reactive barrier for the treatment of mine drainage was used to integrate a comprehensive data set including pore water chemistry and solid phase data from several sampling events over a >3-year time period. The simulations consider the reduction of sulfate by the organic carbon-based treatment material and the removal of sulfate and iron by precipitation of reduced mineral phases including iron monosulfides and siderite. Additional parameters constraining the model include dissolved H2S, alkalinity and pH, as well as a suite of solid phase S-fractions identified by extractions. Influences of spatial heterogeneity necessitated the use of a 2-dimensional modeling approach. Simulating observed seasonal fluctuations and long-term changes in barrier reactivity required the use of temperature dependent rate coefficients and a multimodal Monod-type rate expression accounting for the variable reactivity of different organic carbon fractions. Simulated dissolved concentrations of SO4, Fe, H2S, alkalinity and pH, as well as solid phase accumulations of reduced sulfur phases generally compare well to observed trends over 23 months. Spatial variations, seasonal fluctuations and the time-dependent decline in reactivity were also captured. The modeling results generally confirm, and further strengthen, the existing conceptual model for the site. Overall sulfate reduction and S-accumulation rates are constrained with confidence within a factor of 1.5.