京津冀化工场地地下水污染修复治理对策研究

京津冀化工场地地下水污染问题突出,严重威胁当地饮水安全和可持续发展,亟待开展修复治理.针对京津冀化工场地地下水污染现状,分析了化工场地地下水污染修复面临的挑战,提出了分区分级的修复治理对策.结果表明:①针对可能存在NAPL(非水相液体污染物)的高风险污染源区,采取高强度修复措施,以实现污染物总量的快速削减;②针对中度污染区,采取单位能耗强度更低的长效修复措施,降低修复成本和二次污染风险;③针对低风险的轻度污染区,采取风险管控措施.结合对典型化工场地地下水污染修复技术的分析,提出的分区分级修复治理对策具有以下特点:①多技术耦合,形成互补效应,可提高修复效率;②节约修复成本,降低二次环境影响;③体现基于风险的原则,避免过度修复.      

活性炭强化热活化过硫酸盐降解对硝基苯酚

热活化过硫酸盐（PS）可降解有机污染物,但通常需要较高的反应温度,成为制约降解效率的关键因素之一.为提高热活化PS效率,向反应体系中加入活性炭（AC）并以对硝基苯酚（PNP）为目标污染物,考察AC强化热活化PS降解PNP的效率,分析pH值、PS浓度和AC投加量等因素对PNP降解的影响,确定最佳反应条件.结果表明,AC可以明显强化热活化PS降解PNP,在AC=1.0g/L,PS=2.0mmol/L,PNP=10.0mg/L,T=50℃和pH=3.5条件下,120min时AC/PS体系对PNP降解率可达100.00%,而PS体系对PNP降解率仅为31.69%.自由基猝灭实验表明,AC/PS/PNP体系为自由基反应,SO₄·^-和·OH共同参与PNP降解且以SO₄·^-为主导.机制分析阐明AC上的表面缺陷为活性位点,其与PS中O—O键作用导致O—O键键能降低,进而O—O在热活化下均裂形成SO₄·^-.PNP降解中间产物分析表明AC仅提高了热活化PS降解PNP反应速率,未改变PNP的降解路径.     

除臭剂对填埋场作业面臭气去除效果的试验研究

在等体积的试验桶中放置相同量的生活垃圾,通过喷洒等量的、不同类型的植物型和生物型除臭剂来进行除臭,采用化验分析及人的嗅觉形式来确定试验效果。试验结果显示,微生物型除臭剂对臭气去除的效果优于植物型除臭剂。在喷洒量为100 m L、质量分数为1.0%的情况下,S-1对H_2S、NH_3、臭气的去除率分别为87.4%,41.4%,99.5%;恶臭强度可维持在2~4 h。在3 000 m~2的填埋场作业面喷洒S-1,取得了良好的效果。     

Environmental injustice of informal e-waste recycling in Agbogbloshie-Accra: urban political ecology perspective

This paper provides additional empirical knowledge of injustice embedded in the urban governance of informal-sector electronic waste (e-waste) recycling in Ghana. It uses Urban Political Ecology and Environmental Justice perspectives to explain how divergent interest and power among diverse actors in the e-waste sector engender social and environmental (in)justice in Accra. Using the case study approach, this paper reveals that the persistent struggles over interest and power which characterise the governance and management of informal e-waste recycling generate inequity, false accusations, misrecognition, disrespect, devaluation, neglect, exclusion, and abuse of freedom and rights. Inclusive of the finding is the development of local resistance and social movement in defence of interests and against state aggression, oppression, domination and neglect. The study concludes to suggest that the governance of urban socio-economic and ecological space of Accra should involve coordination, participation, holistic inclusion of diverse interest, so as to minimise trade-offs and reap synergies.     

Restoration planning to guide Aichi targets in a megadiverse country

Ecological restoration has become an important strategy to conserve biodiversity and ecosystems services. To restore 15% of degraded ecosystems as stipulated by the Convention on Biological Diversity Aichi target 15, we developed a prioritization framework to identify potential priority sites for restoration in Mexico, a megadiverse country. We used the most current biological and environmental data on Mexico to assess areas of biological importance and restoration feasibility at national scale and engaged stakeholders and experts throughout the process. We integrated 8 criteria into 2 components (i.e., biological importance and restoration feasibility) in a spatial multicriteria analysis and generated 11 scenarios to test the effect of assigning different component weights. The priority restoration sites were distributed across all terrestrial ecosystems of Mexico; 64.1% were in degraded natural vegetation and 6% were in protected areas. Our results provide a spatial guide to where restoration could enhance the persistence of species of conservation concern and vulnerable ecosystems while maximizing the likelihood of restoration success. Such spatial prioritization is a first step in informing policy makers and restoration planners where to focus local and large‐scale restoration efforts, which should additionally incorporate social and monetary cost–benefit considerations.     

废弃印刷电路板回收拆解过程中的气体排放物分析

为研究废弃印刷电路板(PCB)在回收加热拆解电子元件过程中所产生的气体排放物的主要成分,使用自行设计的废弃PCB拆解装置进行拆解实验,采用傅里叶红外光谱(FTIRS)、气相色谱-质谱(GC/MS)、离子色谱(IC)和电感耦合等离子体质谱(ICP-MS)等分析方法,对实验过程所收集到的气体产物进行成分分析.结果表明,废弃PCB的基板在加热过程中发生了初步分解,基板上的溴化环氧树脂发生了O—C、C—C、C—Br键的断裂,产生了苯酚、2,6-二溴苯酚等有机物;伴随有机气体逸出的还有废弃PCB在加热过程所释放的含有大量S、N、Cl、Br等元素的无机酸性气体;而连续的熔锡过程还使得PCB与焊料中的Sn、Pb、Sb、Hg、Cd、Cr等重金属产生烟尘逸出.     

Electronic waste recycling: A review of U.S. infrastructure and technology options

The useful life of consumer electronic devices is relatively short, and decreasing as a result of rapid changes in equipment features and capabilities. This creates a large waste stream of obsolete electronic equipment, electronic waste (e-waste).Even though there are conventional disposal methods for e-waste, these methods have disadvantages from both the economic and environmental viewpoints. As a result, new e-waste management options need to be considered, for example, recycling. But electronic recycling has a short history, so there is not yet a solid infrastructure in place.In this paper, the first half describes trends in the amount of e-waste, existing recycling programs, and collection methods. The second half describes various methods available to recover materials from e-waste. In particular, various recycling technologies for the glass, plastics, and metals found in e-waste are discussed. For glass, glass-to-glass recycling and glass-to-lead recycling technologies are presented. For plastics, chemical (feedstock) recycling, mechanical recycling, and thermal recycling methods are analyzed. Recovery processes for copper, lead, and precious metals such as silver, gold, platinum, and palladium are reviewed. These processes are described and compared on the basis of available technologies, resources, and material input–output systems.     

基于BP神经网络的垃圾堆放场稳定化程度的综合判别

分析和判别垃圾堆放场的稳定化程度直接关系到是否需要采取加快稳定化进程，缩短垃圾堆放场的稳定化周期以及是否需要采取措施减少它们对环境的不利影响。本文根据我国垃圾堆放场的具体情况，提出稳定化程度的判别评价指标体系，并且确定稳定化程度的判别标准，运用BP神经网络建立垃圾堆放场稳定化程度的综合判别模型。以三峡库区的一个小型垃圾堆放场为例，采用本文所提出的综合评价模型确定它的稳定化程度，演示模型的运行过程，并为三峡库区的环境保护提供帮助。