Air Pollution Steady-State Advection-Diffusion Equation: The General Three-Dimensional Solution

Atmospheric air pollution turbulent fluxes can be assumed to be proportional to the mean concentration gradient. This assumption, along with the equation of continuity, leads to the advection-diffusion equation. Many models simulating air pollution dispersion are based upon the solution (numerical or analytical) of the advection-diffusion equation as- suming turbulence parameterization for realistic physical scenarios. We present the general steady three-dimensional solution of the advection-diffusion equation considering a vertically inhomogeneous atmospheric boundary layer for arbitrary vertical profiles of wind and eddy-diffusion coefficients. Numerical results and comparison with experimental data are shown.

Pollution of Chrome Bearing Materials and the Solutions

This paper summarizes the pollution, situation and solutions of chrome bearing materials used in high temperature industry. Hexavalent chromium compounds are readily soluble in water and associated with carcinogen. Therefore, serious environmental problems appeal for the study and application of chrome free materials. Chrome free products include： magnesia based materials, dolomite based materials, magnesia spinel materials, magnesia hercynite or magnesia galaxite materials and zirconia containing materials,and other substitutes. Although any product has its advantages and disadvantages, the trend to development of chrome free products is inevitable.

Thoughts on Energy Solutions to Alleviation of Air Pollution during the Heating Period in Key Areas

Since the implementation of the Action Plan for Air Pollution Prevention and Control , all regions of China have steadily promoted the prevention and control of air pollution and achieved results continuously. However, the atmospheric environment in key areas such as Beijing-Tianjin-Hebei region, the Yangtze River Delta region, and Fenwei Plain is still severe, and especially during the heating period heavy pollution occurs frequently, which has become the focus and difficulty of improving the quality of the atmospheric environment and is also the weakest link of China s air pollution control at present. How to alleviate air pollution, how to win the battle of pollution prevention and control, how to hold the fruits of the blue sky defense war, energy consumption is key.

Encapsulating the Role of Solution Response Space Roughness on Global Optimal Solution: Application in Identification of Unknown Groundwater Pollution Sources

A major challenge of any optimization problem is to find the global optimum solution. In a multi-dimensional solution space which is highly non-linear, often the optimization algorithm gets trapped around some local optima. Optimal Identification of unknown groundwater pollution sources poses similar challenges. Optimization based methodology is often applied to identify the unknown source characteristics such as location and flux release history over time, in a polluted aquifer. Optimization based models for identification of these characteristics of unknown ground-water pollution sources rely on comparing the simulated effects of candidate solutions to the observed effects in terms of pollutant concentration at specified sparse spatiotemporal locations. The optimization model minimizes the difference between the observed pollutant concentration measurements and simulated pollutant concentration measurements. This essentially constitutes the objective function of the optimization model. However, the mathematical formulation of the objective function can significantly affect the accuracy of the results by altering the response contour of the solution space. In this study, two separate mathematical formulations of the objective function are compared for accuracy, by incorporating different scenarios of unknown groundwater pollution source identification problem. Simulated Annealing (SA) is used as the solution algorithm for the optimization model. Different mathematical formulations of the objective function for minimizing the difference between the observed and simulated pollutant concentration measurements show different levels of accuracy in source identification results. These evaluation results demonstrate the impact of objective function formulation on the optimal identification, and provide a basis for choosing an appropriate mathematical formulation for unknown pollution source identification in contaminated aquifers.

Comparison between Non-Gaussian Puff Model and a Model Based on a Time-Dependent Solution of Advection-Diffusion Equation

A comparison between a non-Gaussian puff model and an advanced time-dependent model to simulate the pollutant dispersion in the Planetary Boundary Layer is presented. The puff model is based on a general technique for solving the K-equation, using the truncated Gram-Charlier expansion (type A) of the concentration field and finite set equations for the corresponding moments. The other model (named ADMM: Analytical Dispersion Multilayers Model) is an semi- analytical solution to the time-dependent two-dimensional advection-diffusion equation based on a discretization of the PBL in N sub-layers;in each sub-layers the advection-diffusion equation is solved by the Laplace transform technique, considering an average value for eddy diffusivity and the wind speed. A preliminary performance evaluation is shown in the case of continuous emission from an elevated source in a variable boundary layer. Both models were able to correctly reproduce the concentration field measured and so to be used as operative air pollution models.

Influence of Fluoride Addition on the Composition of Solutions in Equilibrium with Acid Soils

Atmospheric emissions of fluoride from an aiuminium smelter-alumina refinery located on the northern coast of Galicia, NW Spain, increase the content of fluorine in soils and vegetation in the vicinity of the complex. The effects of the addition of fluoride solutions on the chemical properties of soil samples from the area surrounding the complex were investigated in laboratory experiments. Addition of fluoride to soils resulted in increases in pH and concentrations of Fe, A1, and organic matter in the equilibrium solutions and decreases in concentrations of Ca, Mg, and K. No consistent effects were observed on the Cu, Mn, or Zn concentrations. Most of the A1 in solution was bound to organic matter. Within the fraction ＂labile aluminium＇, the concentration of A1-OH complexes decreased and the A1-F complexes increased, especially A1F3 and A1F4^-, which are less toxic than Al^3＋ and A1-OH species.

Review on the Effects of Combined Pollution of Lead and Chromium on Soil Microorganisms and Treatment Methods

Heavy metals—Pb and Cr are important causes of environmental pollution, and they often coexist in nature. At present, the effects of Pb and Cr toxicity on soil microorganisms have been less studied, in soil environment which is extremely complex. Simulating soil environment and studying microbial reaction under various heavy metal conditions are of great significance for revealing microbial tolerance to heavy metals. In this paper, firstly, the related concepts of soil rechecking pollution are discussed, and the physical and chemical properties and forms of lead and chromium are introduced accordingly. Secondly, the effects of combined pollution of lead and chromium on soil microbial biomass, soil microbial community structure and soil microbial activity were discussed. Finally, the relevant treatment methods of heavy metal contaminated soil were put forward.

Progress in electrocatalytic nitrate reduction for green energy:Catalyst engineering,mechanisms,and techno-economic feasibility

Ammonia(NH_(3))is an irreplaceable chemical that has been widely demanded to keep the sustainable development of modern society.However,its industrial production consumes a huge amount of energy and releases extraordinary greenhouse gases(GHGs),leading to various environmental issues.Achieving the green production of ammonia is a great challenge,which has been extensively pursued in the last decade.In this review,the most promising strategy,electrochemical nitrate reduction reaction(e-NO_(3)RR),is comprehensively investigated to give a complete understanding of its development and mechanism and provide guidance for future directions.However,owing to the complex reactions and limited selectivity,a comprehensive understanding of the mechanisms is crucial to further development and commercialization.Moreover,NO_(3)^(-)RR is a promising strategy for simultaneous water treatment and NH_(3)production.A detailed overview of the recent progress in NO_(3)^(-)RR for NH_(3)production with nontransition and transition metal based electrocatalysts is summarized.In addition,critical advanced techniques,future challenges,and prospects are discussed to guide future research on transition metal-based catalysts for commercial NH_(3)synthesis by NO_(3)^(-)reduction.

Application of Bioengineering in Construction

Bio-cement and bio-concrete are innovative solutions for sustainable construction, aiming to reduce environmental impact while maintaining the durability and versatility of building materials. Bio-cement is an eco-friendly alternative to traditional cement, produced through Microbially Induced Calcium Carbonate Precipitation (MICP), which mimics natural biomineralization processes. This method reduces CO2 emissions and enhances the strength and durability of construction materials. Bio-concrete incorporates bio-cement into concrete, creating a self-healing material. When cracks form in bio-concrete, dormant bacteria within the material become active in the presence of water, producing limestone to fill the cracks, extending the material’s lifespan and reducing the need for repairs. The environmental impact of traditional cement production is significant, with cement generation accounting for up to 8% of global carbon emissions. Creative solutions are needed to develop more sustainable construction materials, with some efforts using modern innovations to make concrete ultra-durable and others turning to science to create affordable bio-cement. The research demonstrates the potential of bio-cement to revolutionize sustainable building practices by offering a low-energy, low-emission alternative to traditional cement while also addressing environmental concerns. The findings suggest promising applications in various construction scenarios, including earthquake-prone areas, by enhancing material durability and longevity through self-repair mechanisms.

养殖池塘水体原位修复技术研究进展

我国作为全球水产养殖大国,养殖规模和产量均居世界首位。池塘养殖是我国最主要的水产养殖模式,在保障优质动物蛋白供给、促进农业增效和农民增收等方面发挥重要作用。随着养殖集约化水平不断提高,养殖密度持续增加,大量饲料投入和动物排泄等导致养殖池塘水体富营养化严重,大量氨氮和亚硝酸盐等不仅污染养殖水体,还会严重危害水产动物健康,导致病害频发、药物滥用、食品安全等一系列问题,给水产养殖绿色可持续发展带来严重挑战,亟需进行养殖池塘水体修复处理。目前,对养殖水体的修复技术主要分为原位修复和异位修复。相较于异位修复,原位修复技术具备节约资源、成本低、无交叉污染等优势,因此具有广阔的应用前景。基于此,该文首先概述了我国养殖池塘水体污染物的主要来源、特征和危害;其次,从物理、化学和生物处理技术3个方面总结了我国养殖池塘水体原位修复技术的研究进展,并详细阐述其技术原理、适用范围、应用效果及优缺点;最后,指出当前池塘养殖水体原位修复存在的主要问题,对未来的研究方向进行展望,并提出一种单塘循环生态养殖模式,为养殖池塘水体修复的未来研究和应用提供参考。

羟基磷灰石在土壤污染修复中的应用研究进展

介绍羟基磷灰石的制备材料和制备方法,以及修复污染土壤的机理,并重点综述了羟基磷灰石对重金属污染土壤修复的效果、对土壤微生物群落结构的改善和对土壤酶活性的提升三个方面的研究进展,并分析了羟基磷灰石的应用优势,提出了羟基磷灰石未来的合成和应用方向。

微塑料对土壤生态系统的影响及其修复技术

由于农膜破碎、污水灌溉等活动,土壤中的微塑料含量与丰度正逐渐超越海洋,并成为土壤的主要污染源之一。土壤生物能吸收土壤微塑料,其中粮食作物中的微塑料能通过食物链进入人体,造成人体微塑料暴露风险,此外,土壤微塑料也会直接对土壤产生毒性。概述了微塑料在土壤生态系统中的来源、迁移等环境行为,重点综述了微塑料对土壤生态系统的影响。结果表明:1)微塑料能通过土壤颗粒间的空隙、植物侧根裂缝及动物运动等在土壤环境系统中迁移转运;2)微塑料能影响土壤物理化学性质、植物生长发育、动物行为和微生物多样性;3)微生物和酶能降解土壤环境中的微塑料,并直接减少土壤系统中的微塑料,而生物炭可以减轻微塑料对土壤生态系统的毒性,三者均为土壤微塑料修复技术的潜在选择。最后,提出了土壤微塑料未来可能的研究方向,以期为土壤微塑料的污染防治提供指导。

蚯蚓-微生物互作调控重金属污染土壤生态系统研究进展

土壤重金属污染是一个全球性环境问题,对生物生存和生态系统可持续发展造成了巨大威胁。生物互作调控重金属污染成为研究热点。阐述了蚯蚓-微生物对土壤重金属的协同作用以及重金属胁迫下蚯蚓-微生物互作影响凋落物分解、土壤碳氮循环、植物生长进而调控土壤生态系统的研究进展,为重金属污染土壤的生物修复提供参考途径。

As和Ni超标矿山土壤对不同桑树品种生长及根际微生物多样性的影响

闭库尾矿库土壤生态修复及土地再生利用,不仅避免了随意排放风险,还能增加土地使用面积。桑树根系旺盛,抗逆性强,生物量大,用途广泛,在矿山重金属超标土壤修复和再利用中具有巨大潜力。本研究采用原土盆栽法比较3个桑树品种(Y120、G12和G62)一年生幼苗在矿区砷(As)和镍(Ni)复合污染土壤中种植60 d后的生长情况,以及桑树不同部位对As和Ni的富集差异,同时采用宏基因组分析桑树根际土壤微生物的差异,初步阐明不同桑树品种对As和Ni复合污染矿山土壤的适应能力及与其根际土壤微生物多样性间的关系。结果表明:种植60d后,3个桑树品种根际土壤Ni的污染指数均从种植前的中度降为轻度,G62根际土壤As的污染指数则从重度污染降为中度污染。3个桑树品种的地上部分和根系生长部分均受到抑制,但G62的生长总体优于Y120和G12,G12生长较差。3个桑树品种对As的转运系数和富集系数均小于Ni,对As的富集能力为根>叶>茎,根部积累As的量占植株总量的47.33%~50.52%,品种间差异较小,但对Ni的富集能力则在不同品种间存在差异,G12、G62、Y120根部Ni积累量占植株总量依次为25.67%、38.46%和47.14%,品种间差异较大。生长较好的G62根际土壤中Nocardioides、Thiomonas和Rhizobium 3个属的丰富度显著高于G12和Y120,其中Thiomonas sp.在G62中丰富度最高,结合G62根际土壤As的污染指数下降较多的事实,说明这些属和种可能更多地参与桑树根际对As的阻隔吸收或解毒。Sphingopyxissp.在G12中丰富度最高,该品种在体内转移和富集的As和Ni均最低,可能与其更多地参与桑树对As和Ni复合污染的解毒有关。研究结果为筛选出适宜矿区生长的抗复合重金属的桑树品种及可促进桑树在As和Ni复合污染矿山土壤生长的菌株筛选和利用奠定基础。

土壤重金属污染微生物修复技术研究进展

随着人类社会的发展,土壤重金属污染引起了社会的广泛关注,现代科学对土壤重金属污染研究的范围也日益深入。常见的物理或化学修复不仅成本高,而且会对环境造成二次污染,亟须寻找一种新的修复方式来对重金属污染的土壤进行修复。本文分别从内生菌、抗性微生物、细菌、真菌以及微生物淋滤法等方面综述了利用微生物修复土壤重金属污染的新技术,以期在未来更好地解决这类问题。

油料作物联合外源添加物强化重金属污染农田修复效果的研究进展

本文综述了螯合剂、氯化物、微生物与油料作物联合的相关研究进展。发现不同联合应用的修复效果和修复机理有所差异,同一油料作物联合三种修复手段产生的修复效果不同,从而修复不同污染类型和污染程度土壤时有更适宜的搭配,为提高油料作物修复效率提供更多新的思路和参考。

Removing and recycling mercury from scrubbing solution produced in wet nonferrous metal smelting flue gas purification process

Wet purification technology for nonferrous metal smelting flue gas is important for mercury removal;however, this technology produces a large amounts of spent scrubbing solution that contain mercury. The mercury in these scrubbing solutions pose a great threat to the environment. Therefore, this research provides a novel strategy for removing and recycling mercury from the scrubbing solution, which is significant for decreasing mercury pollution while also allowing for the safe disposal of wastewater and a stable supply of mercury resources. Some critical parameters for the electrochemical reduction of mercury were studied in detail. Additionally, the electrodeposition dynamics and electroreduction mechanism for mercury were evaluated. Results suggested that over 92.4% of mercury could be removed from the scrubbing solution in the form of a Hg-Cu alloy under optimal conditions within 150 min and with a current efficiency of approximately 75%. Additionally, mercury electrodeposition was a quasi-reversible process, and the controlled step was the mass transport of the reactant. A pre-conversion step from Hg(Tu)_(4)^(2+) to Hg(Tu)_(3)^(2+) before mercury electroreduction was necessary. Then, the formed Hg(Tu)_(3)^(2+) on the cathode surface gained electrons step by step. After electrodeposition, the mercury in the spent cathode could be recycled by thermal desorption. The results of the electrochemical reduction of mercury and subsequent recycling provides a practical and easy-to-adopt alternative for recycling mercury resources and decreasing mercury contamination.

基于低水位运行的城市河流污染底泥中微生物群落特征及影响因素

针对低水位运行修复城市河流污染底泥微生物机制不清的问题,基于高、低水位下不同城市河流的底泥理化性质检测分析、宏基因组高通量测序及生物信息学分析等手段,开展了低水位运行的城市河流污染底泥中微生物群落特征及影响因素研究。结果表明:变形菌门、放线菌门、厚壁菌门和广古菌门分别是不同水位运行条件下相对丰度最高的细菌门类和古菌门类;高水位运行条件下底泥中细菌的香农指数显著高于低水位运行条件下的指数值(p<0.001),古菌则相反,说明古菌群落可能主导了低水位运行过程中底泥污染物降解过程;低水位运行时变形菌门可能是参与底泥中含氮污染物降解以及氮循环过程的主要微生物门类,α-变形菌纲则可能对底泥中氨氮的去除发挥了重要作用;TOC,TN和NH_(3)-N是影响城市河流底泥中微生物群落变化的主要环境驱动因子;低水位运行不仅能够有效降低底泥中常规污染指标的污染程度,解决底泥内源污染问题,还能显著降低底泥中致病菌的潜在危害,构建更为安全的亲水城市河流生态系统。

石油污染土壤微生物群落结构及降污固碳潜力

为探究石油污染土壤中微生物群落结构特征及降污固碳潜力,该研究选取中国东部、中部、西北部、西南部4个典型油气田企业在役井场为研究区域,结合16S rRNA高通量测序及生物信息学技术,研究不同油田表层土壤(0~20 cm)潜在降污、固碳微生物群落结构变化规律及主要驱动环境因子,并针对降污、固碳相关代谢通路进行预测及功能注释。结果表明:(1)不同油田土壤全量养分及微生物生物量大致呈东部油田最高,西南部及西北部油田较为接近,中部油田最低的规律。(2)研究区土壤微生物优势菌为变形杆菌门、放线菌门、绿弯菌门、拟杆菌门,酸杆菌门。(3)基于VPA、RDA分析结果推测,微生物量碳、微生物量氮、RubisCO酶活性、总石油烃含量为影响污染土壤微生物群落结构变化的主要驱动环境因子,其中,TPH(r^(2)=0.67、P=0.001)、MBC(r^(2)=0.36、P=0.0042)、MBN(r^(2)=0.74、P=0.003)和RubisCO酶活性(r^(2)=0.37、P=0.0041)均与微生物群落结构具有显著相关性。(4)KEGG数据库功能注释结果表明,不同油田污染土壤中与微生物固碳过程相关的代谢通路相对丰度均显著高于与石油烃等有机物降解相关的代谢通路,且上述通路在不同油田间的相对丰度差异较小。研究结果为支撑新形势下石油石化行业减污增汇技术发展具有重要意义。