再生水甲醇投加成本运算

再生水资源是水资源的一种特殊形式,它的价格是影响污水回用的重要因素之一。再生水价格有多种形式,其中甲醇的投加是一笔不小的成本。以污水处理厂二级出水为水源进行深度处理以实现污水资源化的过程中,存在着总氮含量高、有机物含量低的水质特点。再生水处理中反硝化阶段需要有机物,也就是碳源。碳源影响脱氮效果,投加甲醇为外碳源可以促进反硝化水平。     

陕西省建设用地增长与碳排放变化的相关分析

通过分析2002~2011年间陕西省建设用地和碳排放的变化,基于LMDI模型分解方法,探讨了10年间建设用地变化对碳排放增长的影响。结果表明:研究时序内,陕西省建设用地和碳排放量均呈增长态势,建设用地年扩展率1.25%,碳排放年均增长8.84%,建设用地变化与碳排放量正向效应显著,建设用地对碳排放的贡献度为12.36%,对建设用地采取总量控制原则,能有效控制碳排放量,对陕西省实现"十二五"期间碳减排目标具有重大意义。     

我国碳储工程环境影响机理及其评价体系研究

在CO2的理化性质及其危险和碳储项目工程分析的基础上,将我国碳储工程划分建设期、运营期、场地关闭及闭场后3大阶段,给出不同阶段工程分析的重点内容。同时,研究与总结了我国碳储工程对地下水、土壤、生态植被和大气等环境影响及其机理,并构建我国深部咸水层CO2地质储存环境影响评价指标体系。该评价体系分为储存场地特征指标类、干扰地质环境指标类、环境容量指标类、生态影响指标类4个层次,为完善我国碳储工程环境影响评价提供依据。     

Fabrication of bimetallic Ag/Fe immobilized on modified biochar for removal of carbon tetrachloride

As an effective conventional absorbent, biochar exhibited limited adsorption ability toward small hydrophobic molecules. To enhance the adsorption capacity, a novel adsorbent was prepared by immobilizing nanoscale zero-valent iron onto modified biochar (MB) and then the elemental silver was attached to the surface of iron (Ag/Fe/MB). It''s noted that spherical Ag/Fe nanoparticles with diameter of 51 nm were highly dispersed on the surface of MB. As the typical hydrophobic contaminant, carbon tetrachloride was selected for examining the removal efficiency of the adsorbent. The removal efficiencies of carbon tetrachloride by original biochar (OB), Ag/Fe, Ag/Fe/OB and Ag/Fe/MB were fully investigated. It''s found that Ag/Fe/MB showed higher carbon tetrachloride removal efficiency, which is about 5.5 times higher than that of the OB sample due to utilizing the merits of high adsorption and reduction. Thermodynamic parameters revealed that the removal of carbon tetrachloride by Ag/Fe/MB was a spontaneous and exothermic process, which was affected by solution pH, initial carbon tetrachloride concentration and temperature. The novel Ag/Fe/MB composites provided a promising material for carbon tetrachloride removal from effluent.     

Paleoenvironmental conditions in the Spanish Miocene–Pliocene boundary: isotopic analyses of Hipparion dental enamel

Expansion of C₄ grasses during Late Miocene and Early Pliocene constitutes one of the most remarkable biotic events of the Cenozoic era. The Teruel–Alfambra region (northeastern Spain) contains one of the most complete Miocene–Pliocene sequences of mammalian fossil sites in the world. In this study, stable isotope (δ ¹³C and δ ¹⁸O) analyses have been performed on the tooth enamel from the equid Hipparion from 19 localities spanning a time interval from approximately 10.9 to 2.7 Ma. This time range starts with the first appearance of this genus in Spain and ends at its extinction. An increase in δ ¹³C at about 4.2 Ma has been observed, indicative of a shift toward a more open habitat. This shift may be related to a large scale vegetation change which occurred across the Miocene–Pliocene boundary when C₄ grasses expanded. This expansion might in turn be linked to global tectonic events such as the uplift of the Himalaya and/or the closure of the Panama Isthmus. However, other more regional factors may have ultimately enhanced the trend toward more open habitats in the Western Mediterranean Basin. The Messinian Salinity Crisis was a major environmental event that may have been responsible for the isotopic changes seen in the equid Hipparion from the Iberian Peninsula along with an increase in the aridity detected ~4.6 Ma ago in the Sahara. Even though the exact factor triggering the isotopic change observed in the Hipparion enamel remains mostly unknown, this study demonstrates that the global environmental changes detected across the Miocene–Pliocene boundary are also recorded in the realm of the Iberian Peninsula. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Assessment of the nitrogen and carbon budget of two managed temperate grassland fields

Greenhouse gas budgets as well as the productivity of grassland systems are closely related to the carbon (C) and nitrogen (N) cycles. Within the framework of the CarboEurope and NitroEurope projects we have measured C and N exchange on the field scale at the grassland site Oensingen previously converted from arable rotation. The site is located on the Swiss Central Plateau and consists of two parallel fields of equal size. One field was subjected to intensive management with average nitrogen input of 230 kg-N ha⁻¹ year⁻¹ and 4–5 cuts per year, and the other to an extensive management with no fertilisation and less frequent cutting. The total C budget of the fields was assessed by measuring the CO₂ exchange by eddy covariance and analysing the carbon import by manure application and export by harvest. The N budget of the managed grassland is more complex. Besides the management related import and export, it includes gaseous exchange in many different forms (NO, NO₂, HNO₃, N₂O, NH₃, N₂) needing different analytical techniques, as well as input by rain and leaching of N-compounds with the soil water. The main (“level-3”) field sites in the NitroEurope project are supposed to measure 95% of the N fluxes at the field scale. For several of the N fluxes specific measurements have been performed for 1 year or longer at the site. Some of the remaining N budget components (dry and wet deposition) could be estimated from results of a national deposition network, while other components (NH₃ and N₂ emission) were estimated based on literature parameterisations. However, we found indications that the (systematic) uncertainties of these estimated N-fluxes are large and that it is important to make site-specific measurement for all relevant budget components. The suitability of corresponding experimental methods is discussed.Analysis of the C budget over a 6-year period (2002–2007) showed a significant mean difference between the two newly established grassland fields with a likely net carbon loss for the extensive management and a net sequestration for the intensive management. Since the C/N ratio of the soil organic matter of the grassland is constrained in a rather narrow range around 9.3, the change in the soil carbon pool is supposed to be accompanied by a corresponding change in the N storage. This approach provided an alternative method to check the N budget of the two grassland fields derived from the individual N fluxes.     

中国发展低碳经济的若干思考

全球气候变化是世界面临的最严峻的环境问题,中国作为发展中国家及温室气体排放大国。急需探索出适合中国发展的低碳之路。中国碳排放总量持续增加,且以工业碳排放为主,严重威胁中国的环境安全与能源安全。中国发展低碳经济主要面临低碳理论欠缺、能源利用效率低、经济发展粗放、以煤炭为主的能源结构等问题．可以从健全相关的政策体系、研发低碳技术和低碳产品、加强公众参与、加强国际合作及树立示范等方面去探索适合中国的低碳经济发展模式。     

直读光谱仪碳元素检出限不确定度分析

依据JJG1059-1999对直读光谱仪碳元素检出限的不确定度进行了评估,分析了影响测量不确定度的各个因素,计算得出直读光谱仪碳元素检出限的扩展不确定度为:U=0.11%,k=2。     

Elevated CO2 reduces the response of Sitobion avenae (Homoptera: Aphididae) to alarm pheromone

The aphid alarm pheromone (E)-β-farnesene (EβF) is an efficient signal that warns aphids of attack by natural enemies. In this field study, eight open-top chambers (OTCs) located in Beijing, China (40°11′N, 116°24′E) with spring wheat Triticum aestivum were used to examine the response of the grain aphid Sitobion avenae to CO₂ (ambient vs. double ambient) and EβF (applied zero, two, or five times each day). We experimentally tested the hypotheses that, depending on frequency of EβF release, elevated CO₂ reduces the response (in terms of population density) of S. avenae to EβF, and that lower activity of acetylcholinesterase (AChE) in S. avenae may be involved in its reduced sensitivity to EβF under elevated CO₂. Numbers of S. avenae declined with increased frequency of EβF application under ambient CO₂ but were unaffected by EβF application under elevated CO₂. Additionally, the mean relative growth rate (MRGR) and the dry material and amino acid content of S. avenae increased with elevated CO₂ but declined when with EβF application. Activities of superoxide dismutase and catalase were higher in S. avenae under elevated vs. ambient CO₂. Under elevated CO₂, however, AChE activity remained low when S. avenae was exposed to the lower EβF frequency, while the highest AChE activity occurred in aphids exposed to the higher EβF frequency. These results indicate that aphids become insensitive to EβF under elevated CO₂, perhaps because of decreased AChE activity.     

Can the envisaged reductions of fossil fuel CO<Subscript>2</Subscript> emissions be detected by atmospheric observations?

The lower troposphere is an excellent receptacle, which integrates anthropogenic greenhouse gases emissions over large areas. Therefore, atmospheric concentration observations over populated regions would provide the ultimate proof if sustained emissions changes have occurred. The most important anthropogenic greenhouse gas, carbon dioxide (CO(2)), also shows large natural concentration variations, which need to be disentangled from anthropogenic signals to assess changes in associated emissions. This is in principle possible for the fossil fuel CO(2) component (FFCO(2)) by high-precision radiocarbon ((14)C) analyses because FFCO(2) is free of radiocarbon. Long-term observations of (14)CO(2) conducted at two sites in south-western Germany do not yet reveal any significant trends in the regional fossil fuel CO(2) component. We rather observe strong inter-annual variations, which are largely imprinted by changes of atmospheric transport as supported by dedicated transport model simulations of fossil fuel CO(2). In this paper, we show that, depending on the remoteness of the site, changes of about 7-26% in fossil fuel emissions in respective catchment areas could be detected with confidence by high-precision atmospheric (14)CO(2) measurements when comparing 5-year averages if these inter-annual variations were taken into account. This perspective constitutes the urgently needed tool for validation of fossil fuel CO(2) emissions changes in the framework of the Kyoto protocol and successive climate initiatives.