Numerical simulation of reactive processes in an experiment with partially saturated bentonite

Bentonites are preferred materials for use as engineered barriers for high-level nuclear waste repositories. Simulation of geochemical processes in bentonite is therefore important for long-term safety assessment of those repositories. In this work, the porewater chemistry of a bentonite sample subject to simultaneous heating and hydration, as studied by Cuevas et al. [Cuevas, J., Villar, M., Fernández, A., Gómez, P., Martín, P., 1997. Porewaters extracted from compacted bentonite subjected to simultaneous heating and hydration. Applied Geochemistry 12, 473-481.], was assessed with a non-isothermal reactive transport model by coupling the geochemical software PHREEQC2 with the object-oriented FEM simulator GeoSys/RockFlow. Reactive transport modelling includes heat transport, two-phase flow, multicomponent transport and geochemical reactions in the liquid phase, i.e. ion exchange, mineral dissolution/precipitation and equilibrium reactions. Simulations show that the easily soluble minerals in bentonite determine the porewater chemistry. Temperature affects both two-phase flow and geochemical reactions. Porosity change due to dissolution/precipitation is low during the experiment. However, changes of the effective porosity caused by bentonite swelling can be very large. The simulated results agree well with the experimental data.     

Atmospheric concentrations and air-sea exchanges of nonylphenol, tertiary octylphenol and nonylphenol monoethoxylate in the North Sea

Concentrations of nonylphenol isomers (NP), tertiary octylphenol (t-OP) and nonylphenol monoethoxylate isomers (NP1EO) have been simultaneously determined in the sea water and atmosphere of the North Sea. A decreasing concentration profile appeared following the distance increasing from the coast to the central part of the North Sea. Air-sea exchanges of t-OP and NP were estimated using the two-film resistance model based upon relative air-water concentrations and experimentally derived Henry's law constant. The average of air-sea exchange fluxes was -12+/-6 ng m(-2)day(-1) for t-OP and -39+/-19 ng m(-2)day(-1) for NP, which indicates a net deposition is occurring. These results suggest that the air-sea vapour exchange is an important process that intervenes in the mass balance of alkylphenols in the North Sea.     

虎耳草和麦冬对生活污水的净化效果研究

分别用虎耳草和麦冬2种陆生植物进行构建小型污水净化系统,与无植物对照组进行对比,研究其在冬季气温条件下,对生活污水的净化效果.实验结果表明,经过27 d的试验,虎耳草和麦冬长势良好,生活污水水质得到明显改善.虎耳草组和麦冬组对试验水体COD的去除率为86.00%和81.91%,TN的去除率为87.38%和82.99%,TP的去除率为88.22%和87.43%,分别较无植物对照组去除率高出3~7、11~15和11~12个百分点.总体来看,虎耳草和麦冬均适用于冬季条件下生活污水的净化,虎耳草净化效果优于麦冬.     

Innovative cleaner production for steel phosphorization using Zn–Mn phosphating solution

Phosphating prior to coating for steel is usually needed. In this paper, an innovative cleaner production has been developed for steel surface treatment using Zn–Mn phosphating solution in which there was no nitrite. The mass of the Zn–Mn layer deposited in this new process was about 1.1 g m^?2 when the temperature ranged from 3 to 35 °C. The corrosion time for the color phosphating layer in the copper sulfate spot test was in the range of 72–145 s. Adhesion test showed that the coating layers achieved a higher adhesion load than those produced by conventional methods. Washing using water was not necessary in this cleaner phosphorization, which usually follows phosphorization in traditional processes of steel phosphorization. Consequently, wastewater discharge was reduced greatly.     

水文地球化学热力学在山西省辛安泉氮污染预测中的运用

山西省辛安泉是长治地区的主要供水水源，目前它的部份泉城域已遭到了严重的氮污染，本文在环境水文地质地球化学调查的基础上，应用水文地球化学热力学理论，对氮化牧在岩溶水中转化方向，平衡组成进行了分析，并用稀释环境容量方法，作出了辛安泉氮污染预测初步评价。这表明在水文地质地球化学研究程度不足以建立溶质运移确定型模型时，水文地球化学方法是研究氮污染预测的一种有效的近似方法。     

西岭雪山风景名胜区水质评价研究

本文根据西岭雪山风景区的生态、环境特征和水质标准，选择了８个评价指标，对８个采样带和全游览景区的水体质量，运用模糊数学方法进行了综合评价研究     

Black and Smelly Waters: how citizen-generated transparency is addressing gaps in China’s environmental management

ABSTRACT

Information communication technologies (ICTs) generate new forums for transparency via governance-by-disclosure initiatives designed to improve environmental management and policy. Data generated by these programs are a means to empower citizens, narrowing the accountability gap between governments and people and enhancing public service. There is little empirical evidence, however, that supports the theory that citizen-generated data can be used to improve the accountability of local government officials. Citizen-led transparency efforts are emerging in China, as the country undergoes an information revolution that has brought ICTs to near ubiquity. We evaluate the transformative potential of a new ICT initiative, the ‘Black and Smelly Waters’ program, which China’s government launched to help enforce local government water remediation efforts. Many examples of citizen-generated transparency are grassroots initiatives, yet the Black and Smelly Waters program is distinct in its top-down structure. An empirical evaluation of preliminary data illuminates Black and Smelly Waters’s early successes and challenges as a means to generate transparency and accountability. We discuss these findings and propose a broad application of this new type of disclosure to reshape environmental management in China.     

试谈建立沱江源头水源保护区的必要性

本文根据沱江源头水源涵养林辽度砍代，导致源头蓄水量锐减，以及滥采乱控矿石，造成资源损失与灾害频繁的严峻现实，提出了建立沱江源头水源保护区的必要性。