电化学法去除有机污染物机理研究进展

电化学方法因其所具有的多功能性、操作简单、易于自动化并且具有环境兼容性等特点而倍受人们重视。近年来 ,国内外研究者对该方法在水处理中的应用进行了广泛的研究 ,并对有机污染物电化学降解机理提出了不同观点 ,本文对这些观点进行了分类 ,并对其中的主要观点进行论述     

Competing esterification and oligomerization reactions of typical long-chain alcohols to secondary organic aerosol formation

Organosulfate (OSA) nanoparticles,as secondary organic aerosol (SOA) compositions,are ubiquitous in urban and rural environments.Hence,we systemically investigated the mechanisms and kinetics of aqueous-phase reactions of 1-butanol/1-decanol (BOL/DOL) and their roles in the formation of OSA nanoparticles by using quantum chemical and kinetic calculations.The mechanism results show that the aqueous-phase reactions of BOL/DOL start from initial protonation at alcoholic OH-groups to form carbenium ...     

Monitoring requirements for groundwaters under the influence of reclaimed water

Monitoring groundwaters under the influence of reclaimedwater must consider the major constituents of concern inreclaimed water. This research focused on the fate ofdissolved organic carbon and nitrogen species at field siteslocated throughout the Southwestern United States. Awatershed approach was developed to predict the fate ofdissolved organic carbon as a function of the drinking waterdissolved organic carbon concentration and the totaldissolved solids concentration in the reclaimed water. Extensive characterization of the dissolved organic carbonrecovered from groundwaters under the influence of reclaimedwater was done. With the exception of fluorescencespectroscopy, the dissolved organic carbon present ineffluent organic matter was similar in structure, characterand reactivity as compared to natural organic matter. Evidence for sustainable nitrogen removal mechanisms duringgroundwater recharge with reclaimed water was obtained. Theautotrophic reaction between ammonia and nitrate appears to amechanism for the removal nitrogen in a carbon-depletedenvironment. The monitoring tools and methodologiesdeveloped in this research can be used to assure protectionof public health and determine the sustainability of indirectpotable reuse projects.     

金属铁还原脱氯处理有机氯化物的研究进展

本文对金属铁在还原降解六氯乙烷、四氯化碳、氯仿、三氯乙烯、四氯乙烯、二氯乙烯、氯乙烯、五氯酚、多氯联苯等有机氯化物中的应用作了评述 ,讨论了金属铁降解有机氯化物的反应机理及动力学。     

Banging heads onboard buses: Assessment scheme to improve injury mitigation for bus passengers

Abstract

Objective: Although bus travel is one of the safest modes of transport, a substantial number of bus passengers in London are still injured in collision and harsh maneuver incidents, in particular emergency braking. It is not well understood how these passengers are injured. The objective was to better understand the injury mechanisms and develop countermeasures with a test and assessment procedure to prevent or mitigate these injuries.

Methods: The UK national STATS19 data were used to determine the size of the problem. Data, including CCTV footage, in combination with inspection of current buses, were used to determine injury mechanisms and identify features and areas in buses associated with more injuries.

An assessment system based on visual inspection was developed to encourage a reduction in the number of features associated with injury.

Results: The STATS19 analysis showed that three quarters of all injured casualties occurred in incidents where there was no impact, with this proportion rising for seriously injured casualties. Overrepresentation of older females was also seen.

The CCTV analysis and bus examinations highlighted issues with poorly positioned handrails, lack of compartmentalization (restraint), and objects with sharp edges and corners. It also showed that a much higher proportion of passengers seated in the area close to the middle doors and wheelchair area were injured compared to other areas of the bus. Factors contributing to this result were that this area contained more features associated with injury and that persons with reduced mobility have greater exposure in this area; that is, more vulnerable passengers currently sit in the less safe areas of the bus.

Conclusions: A novel analysis of CCTV footage has enabled a better understanding of injury mechanisms for bus passengers to be developed. In combination with inspection of current buses, this has been used to develop an assessment system to improve the safety of buses in London.     

Inactivation and risk control of pathogenic microorganisms in municipal sludge treatment: A review

• Diversity and detection methods of pathogenic microorganisms in sludge. • Control performance of sludge treatment processes on pathogenic microorganisms. • Risk of pathogen exposure in sludge treatment and land application. The rapid global spread of coronavirus disease 2019 (COVID-19) has promoted concern over human pathogens and their significant threats to public health security. The monitoring and control of human pathogens in public sanitation and health facilities are of great importance. Excessive sludge is an inevitable byproduct of sewage that contains human and animal feces in wastewater treatment plants (WWTPs). It is an important sink of different pollutants and pathogens, and the proper treatment and disposal of sludge are important to minimize potential risks to the environment and public health. However, there is a lack of comprehensive analysis of the diversity, exposure risks, assessment methods and inactivation techniques of pathogenic microorganisms in sludge. Based on this consideration, this review summarizes the control performance of pathogenic microorganisms such as enterovirus, Salmonella spp., and Escherichia coli by different sludge treatment technologies, including composting, anaerobic digestion, aerobic digestion, and microwave irradiation, and the mechanisms of pathogenic microorganism inactivation in sludge treatment processes are discussed. Additionally, this study reviews the diversity, detection methods, and exposure risks of pathogenic microorganisms in sludge. This review advances the quantitative assessment of pathogenic microorganism risks involved in sludge reuse and is practically valuable to optimize the treatment and disposal of sludge for pathogenic microorganism control.     

山东省农业多功能的时空演化特征与驱动机制分析

农业供给侧改革与乡村振兴背景下,深入挖掘各地区农业多种功能,统筹不同农业功能特征地域的协调发展,成为促进农业增收、实现农业可持续发展、保障食物安全的关键。农业多功能的演变受到区域农业资源禀赋与社会经济发展水平和阶段的复杂影响。以山东省为例,选取2004年、2011年、2017年三个时间截面,构建农业多功能评价指标体系,运用空间错位指数、回归分析等方法对县域农业多功能的时空演变规律与驱动机制进行分析。研究发现：（1）2004—2017年,山东省农业的农产品供给功能和经济发展功能分别呈先升后降和先降后升的增长态势,社会保障功能和生态服务功能分别呈持续下降和先降后升的下降趋势。（2）研究期内,农产品供给功能与生态服务功能对农业资源禀赋依赖较强,分别呈现出沿平原—丘陵—山地递减与递增的空间格局;经济发展功能与社会保障功能受社会经济发展水平和阶段影响较大,时空差异明显。（3）各驱动因子对于同一功能中不同要素的作用方向与强度存在差异,引发农业各功能结构的变化。基于功能视角提出山东省农业转型发展的路径选择与分区优化策略。     

Modeling particle loss in ventilation ducts

Empirical equations were developed and applied to predict losses of 0.01–100 μm airborne particles making a single pass through 120 different ventilation duct runs typical of those found in mid-sized office buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles larger than 50 μm. The 50th percentile cut-point diameters were 15 μm in supply runs and 25 μm in return runs. Losses in supply duct runs were higher than in return duct runs, mostly because internal insulation was present in portions of supply duct runs, but absent from return duct runs. Single-pass equations for particle loss in duct runs were combined with models for predicting ventilation system filtration efficiency and particle deposition to indoor surfaces to evaluate the fates of particles of indoor and outdoor origin in an archetypal mechanically ventilated building. Results suggest that duct losses are a minor influence for determining indoor concentrations for most particle sizes. Losses in ducts were of a comparable magnitude to indoor surface losses for most particle sizes. For outdoor air drawn into an unfiltered ventilation system, most particles smaller than 1 μm are exhausted from the building. Large particles deposit within the building, mostly in supply ducts or on indoor surfaces. When filters are present, most particles are either filtered or exhausted. The fates of particles generated indoors follow similar trends as outdoor particles drawn into the building.     

微生物降解土壤中农药残留的研究进展

研究土壤环境中农药的微生物降解是当今国际环境修复科学技术前沿领域的重要课题.从降解农药的微生物种类、降解农药的途径及机理、基因工程菌的构建等方面综述了近年来的研究进展,并提出了微生物降解农药研究领域的发展趋势和有待进一步解决的一些突出问题.     

多相催化臭氧氧化技术机理研究进展

多相催化臭氧氧化技术能够有效去除水中的微量有机物。尽管有越来越多的研究致力于多相催化臭氧氧化技术领域,以及各种新的催化剂的引入,但对于多相催化臭氧氧化技术机理尚不清楚。因此,本文针对多相催化臭氧氧化技术中常用的负载型金属、负载型金属氧化物以及活性炭三类催化剂的反应机理进行了探讨。此外还对机理研究中存在的问题进行了探讨。