粒状铁与甲醇支持的生物-化学联用法去除富氧地下水中硝酸盐

针对富氧地下水中硝酸盐,采用粒状铁和甲醇支持的生物-化学联用法开展了批实验研究,优化了脱氮反应参数,初步探讨了脱氧脱氮的能力及途径。结果表明,该法的优化参数是粒状铁种类为GI-北京,m（粒状铁）∶m（水）为3∶800,粒状铁粒径为0.425~1.0 mm,反应时间为5 d,甲醇用量为210.59 mg.L-1。生物-化学法、粒状铁和好氧异养菌完全脱氧所需的时间分别是174、206和2 746 min。生物-化学法脱氧依赖于粒状铁化学还原和好氧异养菌有氧呼吸,并且前者起着关键作用。随着反应时间的增加,异养脱氮、自养脱氮和化学还原各自引起的NO3-去除率亦增加。当反应时间≤5 d时,自养脱氮和化学还原的去除率均〈10%,而当反应时间为5 d时,生物-化学法的NO3-去除率达到近100%。生物-化学法内存在异养脱氮、自养脱氮和化学还原3种脱氮途径,其中异养脱氮是最主要的途径,且三者存在共生、协同和促进作用。生物-化学法脱氮期间硝酸盐还原速率≥亚硝酸盐还原速率。生物-化学法去除地下水中硝酸盐是有效可行的。     

Parametric approach of the domino effect for structural fragments

More specific and accurate probabilistic models of the numbers of fragments generated respectively by Boiling Liquid Expanding Vapor Explosions (BLEVEs), Mechanical Explosions (MEs), Confined Explosions (CEs), and Runaway Reactions (RRs) of a horizontal cylindrical vessel were developed using the maximum entropy principle based on historical accident data. The theoretical results from the four probability density functions were compared to the observed data, and the numbers of fragments followed discrete exponential distributions in the interval [1, 9]. Beside the summary of the probabilistic distributions of the other random variables in the process of fragment projection, the effects on the fragment trajectory and target terms were investigated using a parametric approach. The results showed that using the complete model, wind shear, turbulence, and absence of fragment rotation caused the fragments to impact within shorter distances; fragment rotation and lack of wind decreased the probability of impact within a given distance, but the rupture probability of the target was not affected by fragment rotation or wind. The probabilistic confidence intervals of fragment range, impact, and target penetration became narrower with the number of simulation runs, but the accuracy of the results increased. The probability of fragment impact increased with the volume of the target vessel and the degree of filling of the explosion vessel, but did not depend on the kind of explosion. The probability of target rupture increased slowly with the degree of filling of the explosion vessel, but was little influenced by the volume of the target vessel or the kind of explosion.     

基于循证方法的施工现场安全事故预防体系研究

为提高施工现场安全绩效,构建基于循证方法的施工现场安全事故预防体系。阐明施工现场安全循证预防(EBP)的定义、内涵、核心思想,梳理循证预防解决安全问题的思路,并且提出施工现场安全管理循证预防的流程框架。结果表明:针对施工现场安全事故预防中的不足,循证方法解决问题的思路体现在理论和方法 2个层面;施工现场安全管理循证预防体系分为循证诊断和循证干预2个阶段,具体包括安全检查表、框架表示法、荟萃(Meta)分析等关键步骤。     

生态工业系统分析方法

生态工业系统分析方法是生态工业理论中的核心内容,是分析生态工业系统在实践过程中成效的重要方法论。对生态工业系统分析方法———生态工业系统性质分析、生态工业系统影响因素分析、生态工业系统网络分析、生态工业系统刚性分析、生态工业系统稳定性初步分析等5个方面进行了较为详细的阐述。     

应用相平衡分配法建立污染物的沉积物质量基准

以污染较为严重的天津某污水库的表层沉积物为对象,应用热力学相平衡分配(EqP)法,初步探讨了该水体沉积物中4种重金属(Cd,Cu,As,Hg)和2种有机氯农药〔滴滴涕(DDT)、六六六(HCH)〕的沉积物质量基准(SQC)推荐值. 其中,基于我国地表水水质基准的4种重金属Cd,Cu,As和Hg的SQC推荐值分别为4.3,86,218和0.45 mg/kg;基于美国环境保护署(US EPA)的保护水生生物水质基准的2种有机氯农药(DDT和HCH)的SQC推荐值分别为18.0和0.27 μg/kg. 通过与不同国家制订的SQC值进行比较发现,地区间的SQC值相差较大,说明在SQC值的确定过程中存在诸多不确定因素. 所推算出的几种污染物的SQC值均接近所有数据的中间值,表明其可为该水体沉积物的风险评估提供依据.      

Surface installations intended for Carbon Capture and Sequestration: Atypical accident scenarios and their identification

With the advent of Carbon Capture and Sequestration (CCS) technology the extent of CO₂ handling is set to increase dramatically. However, lack of substantial operational experience in such a novel process can lead to significant difficulties in identifying the associated hazards. This field may be characterized by atypical accident scenarios, i.e. scenarios not captured by common HAZard IDentification (HAZID) techniques because of omissions, errors or lack of knowledge. Recent atypical events evidence that consequences may exceed by far those of worst-case reference scenarios. Identification of atypical scenarios related to CCS is a challenge, considering also the public concern that this technology raises. This study focuses on new and emerging technologies of carbon capture and transport. A HAZID analysis was carried out by means of two different approaches (‘top-down’ and ‘DyPASI’). This allowed not only for a double check of results, but also for the comparative assessment of the methodologies and of their applicability. A general overview of the accident scenarios related to these technologies was given. No absolute showstoppers were found. Rather, a number of potential hazards were identified which will require the adoption of safe design principles to eliminate, prevent, control or mitigate them. Some possible safety barriers required for implementation were identified as a starting point in this process.     

Combustion products toxicity risk assessment in an offshore installation

Products of a hydrocarbon fire accident have both chronic and acute health effects. They cause respiratory issues to lung cancer. While fire is the most frequent phenomenon among the offshore accidents, predicting the contaminants’ concentration and their behavior are key issues. Safety measures design, such as ventilation and emergency routes based only on predicted contaminants’ concentration seems not to be the best approach. In a combustion process, various harmful substances are produced and their concentration cannot be added. The time duration that any individual spends in different locations of an offshore installation also varies significantly. A risk-based approach considers the duration a person is exposed to contaminants at various locations and also evaluates the hazardous impacts. A risk-based approach has also an additivity characteristic which helps to assess overall risk.Through the current study, an approach is proposed to be used for risk assessment of combustion products dispersion phenomenon in a confined or semi-confined facility. Considering CO, NO₂ and CH₄ as the contaminants of concern, the dispersion of the substances over the layout of the facility after a LNG fire is modeled. Considering different exposure times for three major parts of the facility including the processing area, office area and the accommodation module, the risk contours of CO, NO₂ and CH₄ over the entire facility are developed. The additivity characteristic of the risk-based approach was used to calculate the overall risk. The proposed approach helps to better design safety measures to minimize the impacts and effective emergency evacuation planning.     

Estimating the mitigation effect of Tokai earthquake measures on housing damage: a counterfactual approach

This paper evaluates the mitigation effect of Tokai earthquake measures on housing damage using a counterfactual approach. It focuses on those measures that stimulate ex‐ante investment in disaster prevention in the supposedly affected area, including earthquake‐proof retrofitting and improved housing construction; the effect of the measures on housing losses is estimated monetarily. The study compares factual disaster damage computed using a real distribution of houses with counterfactual damage to a hypothetical housing distribution that would occur if the measures were not implemented. The key findings are: (i) the disaster mitigation effects of Tokai earthquake measures on housing amount to approximately JPY 18 billion (USD 0.18 billion) for Yamanashi Prefecture and JPY 0.26 trillion (USD 2.6 billion) for Shizuoka Prefecture, which would be at the centre of the event; (ii) a before–after comparison biases estimates of the mitigation effect; and (iii) statistically, the measures do not mitigate the housing damage predicted for an earthquake in Tokai.     

Building resilience by challenging social norms: integrating a transformative approach within the BRACED consortia

Resilience is a complex phenomenon whereby a multitude of social and environmental factors, including gender, combine to shape the ways that shocks affect people. Looking at two BRACED (Building Resilience and Adaptation to Climate Extremes and Disasters) projects, in Burkina Faso and in Ethiopia, this article uses a desk review and primary data from partners and people at risk to explore how a gender‐transformative approach can be an integral part of resilience‐building projects, particularly those implemented by multi‐stakeholder consortia. It also suggests ways to incorporate a stronger gender component in similar future projects. The article argues that donors and programme managers must provide clear principles and guidelines for achieving gender equity within resilience‐building efforts. However, these must allow flexibility to adapt to norms, needs and resources as determined by implementing partners. The right balance can be achieved by facilitating spaces for individual and collective goal‐setting; assessing current capacity and trajectories; and lesson‐sharing as an iterative process for institutional learning.     

The derivation of discount rates with an augmented measure of income

Most developed economies invest in public goods such as national defense, education, infrastructure, and the environment. Discount rates used to evaluate such projects should reflect the rate of return on the current mix of investment opportunities. Rates derived from the productivity of private capital neglect returns beyond the market boundary. The present paper derives discount rates using an augmented measure of national income inclusive of non-market goods. In an empirical application focusing on air pollution and climate damages in the United States economy, the paper reports that the difference between augmented and market discount rates averages 0.3 percentage points from 1999 to 2014.