Zinc recovery from hazardous construction wastes via an integrated process of the air classification,alkaline leaching,and water washing

Zinc- and lead-containing wastes are often mixed with construction and demolition wastes in many factories, generating abundant of heavy metal-enriched hazardous waste. In the present study, a novel integrated process of air classification, alkaline leaching, and water washing dechlorination was proposed for the efficient recycling of Zinc (Zn) resources. The first air classification process was realized via venturi tube, wherein the content of Zn could increase by 20 wt.%. After that, the product underwent an alkaline leaching process. Results showed that Zn recovery rate increased with fine particle sizes, and a 65% recovery rate was obtained under the following conditions of 5 mol/L NaOH, liquid/solid 10:1, and leaching time 1 h. Finally, water washing associated with microwave and ultrasonic treatments could remove over 85% of Cl and other water-soluble salts. All the results indicated that the integrated method had an excellent recovery rate for Zn resources from construction and demolition wastes.     

Assessing the Effectiveness of Winter Cover Crops for Controlling Agricultural Nutrient Losses

A nutrient loss reduction strategy is necessary to guide the efforts of improving water quality downstream of an agricultural watershed. In this study, the effectiveness of two winter cover crops, namely cereal rye and annual ryegrass, is explored as a loss reduction strategy in a watershed that ultimately drains into a water supply reservoir. Using a coupled optimization-watershed model, optimal placements of the cover crops were identified that would result in the tradeoffs between nitrate-N losses reduction and adoption levels. Analysis of the 10%, 25%, 50%, and 75% adoption levels extracted from the optimal tradeoffs showed that the cover crop placements would provide annual nitrate-N loss reductions of 3.0%–3.7%, 7.8%–8.8%, 15%–17.5%, and 20.9%–24.3%, respectively. In addition, for the same adoption levels (i.e., 10%–75%), sediment (1.8%–17.7%), and total phosphorus losses (0.8%–8.6%) could be achieved. Results also indicate that implementing each cover crop on all croplands of the watershed could cause annual water yield reduction of at least 4.8%, with greater than 28% in the months of October and November. This could potentially be detrimental to the storage volume of the downstream reservoir, especially in drought years, if cover crops are adopted in most of the reservoir's drainage area. Evaluating water yield impacts, particularly in periods of low flows, is thus critical if cover crops are to be considered as best management practices in water supply watersheds.     

Five-wheel framework for system-based monitoring of heavy metal pollution in rivers

Sectorial approach for monitoring heavy metal pollution in rivers has failed to report realistic pollution status and associated ecological and human health risks. The increasing spread of heavy metals from different sources and emerging risks to human and environmental health call for reexamining heavy metal pollution monitoring frameworks. Also, the sources, spread, and load of heavy metals in the environment have changed significantly over time, requiring consequent modification in the monitoring frameworks. Therefore, studies on heavy metal monitoring in rivers conducted in the last decade were evaluated for experimental designs, research frameworks, and data presentations. Most studies (∼99%) (i) lacked inclusiveness of all environmental compartments; (ii) focused on “one pollutant – one/two compartment” or sometimes “one pollutant – one compartment – one effect” approach; and (iii) remained “data-rich but information poor.” An ecological approach with integrative system thinking is proposed to develop a holistic approach for monitoring river pollution. It is visualized that heavy metal monitoring, risk analyses, and water management must incorporate tracking pollutants in different environmental compartments of a river (water, sediment, and floodplain/bank soil) and consider correlating it with riverbank land use. The systems-based pollution monitoring and assessment studies will reveal the critical factors that drive heavy metals pollutant movement in ecosystems and associated potential risks to the environment, wildlife, and humans. Also, water quality and pollution indexing tools would help better communicate complex pollution data and associated risks among all stakeholders. Therefore, integrating systems approaches in scientific- and policy-based tools would help sustainably manage the health of rivers, wildlife, and humans.     

Preserving Wilderness or Protecting Homelands? Intersections and Divergences in Activist Discourses About Mining in Ontario’s Far North

Northern Ontario’s Ring of Fire/Wawangajing controversy constitutes a complex site of debate about the risks and benefits of mining in an area of major ecological significance that is also the ancestral territory of nine First Nation communities. This paper investigates the rhetorical alignments and divergences in public calls by Matawa First Nations tribal council and the Ontario Wildlands League for stronger environmental assessment of mining projects than that favoured by the Canadian government. Tracing the terminologies each group uses to describe the affected region and its inhabitants in its activist rhetoric about EA offers insight into the contingent, shifting ways in which wilderness advocacy and Indigenous justice discourses may speak together yet distinctly within contemporary environmental-natural resource disputes.     

基于TVR的腐蚀油气管道失效概率及安全寿命研究

为避免因腐蚀导致油气管道失效，针对因管道特性和腐蚀尺寸的不确定性使得管道剩余强度成为概率模型的特点，建立了腐蚀管道强度损失随机模型；借助可靠性理论，通过分析管道腐蚀进程的时变性特点，将管道系统由损伤积累和抗力衰减导致的剩余强度随机化；提出基于穿越率的腐蚀油气管道失效评定及安全寿命预测方法。研究结果表明:腐蚀速率和运行压力对管道失效概率及安全寿命影响显著,管道尺寸影响适中，而相关系数和拉伸强度影响较小；若腐蚀速率Va=0.2 mm/a，VL=10 mm/a或局部腐蚀缺陷半径达到管道壁厚的0.5倍时，建议作为重点风险段监测并检修。所建方法是对腐蚀油气管道运营监控和风险评估的有益补充。     

Mainstreaming human and large carnivore coexistence through institutional collaboration

Achieving coexistence between large carnivores and humans in human-dominated landscapes (HDLs) is a key challenge for societies globally. This challenge cannot be adequately met with the current sectoral approaches to HDL governance and an academic community largely dominated by disciplinary sectors. Academia (universities and other research institutions and organizations) should take a more active role in embracing societal challenges around conservation of large carnivores in HDLs by facilitating cross-sectoral cooperation to mainstream coexistence of humans and large carnivores. Drawing on lessons from populated regions of Europe, Asia, and South America with substantial densities of large carnivores, we suggest academia should better embrace the principles and methods of sustainability sciences and create institutional spaces for the implementation of transdisciplinary curricula and projects; reflect on research approaches (i.e., disciplinary, interdisciplinary, or transdisciplinary) they apply and how their outcomes could aid leveraging institutional transformations for mainstreaming; and engage with various institutions and stakeholder groups to create novel institutional structures that can respond to multiple challenges of HDL management and human–large carnivore coexistence. Success in mainstreaming this coexistence in HDL will rest on the ability to think and act cooperatively. Such a conservation achievement, if realized, stands to have far-reaching benefits for people and biodiversity.     

浅谈县级环境监测质量管理工作现状及对策

当前环保系统垂直改革稳步推进,县级环境监测质量管理工作也迎来新的机遇与挑战。从县级环境监测站质量管理工作现状着手,分析新形势下存在质量管理体系有效性缺乏、现场监测过程质量管理薄弱、质量管理意识尚待提高等问题。提出,应从加强体系建设、提高现场监测水平、强化考核培训力度等方面改进县级环境监测质量管理工作水平。     

“Hey Friend,Buy Green”: Social Media Use to Influence Eco-Purchasing Involvement

This study addresses the use of message carriers to convey corporate social responsibility information to promote eco-purchasing involvement. The work tests various media formats transmitted via social media. The effects of corporate vs. peer communication in a corporate social responsibility campaign in stimulating self-reported eco-purchasing involvement are indicated. The research varies communication dimensions of a fictional corporate social responsibility campaign sent through social media. Multiple media formats; new release; article; and advertisement were tested, as was the inclusion of social media persuasive sentiment. The analysis of source/format combinations and source/format/sentiment combinations found statistically significant differences for consumer-to-consumer communication in stimulating eco-purchasing involvement in certain circumstances. This research suggests an emerging role for the consumer communicator as a content co-creator and validates the effective use of articles and news releases instead of advertising on social media, yielding managerial and scholarly implications.     

Difference in the net value of ecological services between natural and artificial forests in China

Land degradation is a global problem that seriously threatens human society. However, in China and elsewhere, ecological restoration still largely relies on a traditional approach that focuses only on ecological factors and ignores socioeconomic factors. To improve the effectiveness of ecological restoration and maximize its economic and ecological benefits, a more efficient approach is needed that provides support for policy development and land management and thereby promotes environmental conservation. We devised a framework for assessing the value of ecosystem services that remain after subtracting costs, such as the opportunity costs, costs of forest protection, and costs for the people who are affected by the program; that is, the net value of ecosystem services (NVES). To understand the difference between the value of a resource and the net value of the ecosystem service it provides, we used data on VES, timber sales, and afforestation costs from China's massive national afforestation programs to calculate the net value of forest ecosystem services in China. Accounting for the abovementioned costs revealed an NVES of ¥6.1 × 10¹² for forests in 2014, which was 35.9% less than the value calculated without accounting for costs. As a result, the NVES associated with afforestation was 55.9% less than the NVES of natural forests. In some regions, NVES was negative because of the huge costs of human-made plantations, high evapotranspiration rates (thus, high water opportunity costs), and low forest survival rates. To maximize the ecological benefits of conservation, it is necessary to account for as many costs as possible so that management decisions can be based on NVES, thereby helping managers choose projects that maximize both economic and ecological benefits.     

臭氧氧化—湿式钙法吸收工艺对烟气的同时脱硫脱硝

采用臭氧氧化—湿式钙法吸收工艺对模拟烟气进行同时脱硫脱硝处理。O₃于150 ℃下具有较高的热稳定性,可将NO氧化为高价态氮氧化物,且NO氧化率随n（O₃）∶n（NO）的增大而逐渐提高。烟气中SO₂和H₂O的存在对NO氧化率的影响不大。O₃对SO₂的氧化率较低,约为5%。3%（w）石灰石浆液对SO₂的吸收率接近100%,NO_x吸收率随n（O₃）∶n（NO）的增大而逐渐提高,当n（O₃）∶n（NO）为1.6时NO_x吸收率可达约65%。SO₂能促进吸收液对NO_x的脱除。石灰石浆液中加入0.2%（w）的（NH₄）₂SO₃或Na₂SO₃后NO_x吸收率可达约85%或82%,且吸收率随添加剂加入量的增加而提高,添加（NH₄）₂SO₃的NO_x吸收率略高于添加Na₂SO₃。