软包装印刷的有机废气净化和溶剂回收工艺研究

为了促进企业开展节能减排和资源回用,在车间选取了一条干式复合线进行废气净化和溶剂回收及利用工艺研究,使用乙酸乙酯作为粘胶剂的稀释剂,废气净化和溶剂回收采用吸附浓缩+冷凝回收工艺,溶剂脱水提纯采用渗透汽化膜分离工艺.结果表明,这两种工艺组合十分适合干式复合线的溶剂回收和溶剂脱水提纯,处理装置具有溶剂回收率高、纯度好、运行...     

2005～2009年南京市二氧化碳排放特征研究

采用IPCC报告(2006版)提供的计量方法与碳含量缺省值,对南京市能源消费碳排放进行了计量研究.结果表明:从2005～2009年,CO2排放总量从8.05×107t增加到1.02×108t,人均CO2排放量从11.7 t/a增加到13.2 t/a,但CO2排放强度持续降低,从3.34 t/万元下降到2.41 t/万元...     

Carbon balance of an intensively grazed temperate pasture in two climatically contrasting years

Grazed grasslands occupy 26% of the earth's ice free land surface and are therefore an important component of the global C balance. In New Zealand, pastoral agriculture is the dominant land use and recent research has shown that soils under intensive dairy pastures have lost large amounts of carbon (∼1000 kg C ha⁻¹ y⁻¹) during the past few decades. The objective of this research was to determine the net ecosystem carbon balance (NECB) of an intensively grazed dairy pasture in New Zealand. Net ecosystem CO₂ exchange (NEE) was measured using an eddy covariance (EC) system from 1 January 2008 to 31 December 2009. Other C imports (feed) and exports (milk, methane, leaching, and harvested biomass) were calculated from farm production data and literature values. During 2008 there was a one in 100 year drought during summer/autumn, which was followed by a very wet winter. There were no prolonged periods of above or below average rainfall or soil moisture in 2009, but temperatures were consistently lower than 2008. The severe summer/autumn drought during 2008 caused a loss of CO₂ to the atmosphere, but annual NEE remained negative (a CO₂ sink, −1610 ± 500 kg C ha⁻¹), because CO₂ lost during the drought was regained during the winter and spring. The site was also a net CO₂ sink during 2009 despite the colder than usual conditions (−2290 ± 500 kg C ha⁻¹). Including C imports and exports in addition to CO₂ exchange revealed that the site was a C sink in both years, with a NECB of 590 ± 560 kg C ha⁻¹ in 2008, and 900 ± 560 kg C ha⁻¹ in 2009. The C sequestration found in this study is in agreement with most other Northern Hemisphere EC studies of grazed pastures on mineral soils, but is not consistent with the large C losses reported for soils under dairy pastures throughout New Zealand. In the current study (like many other EC studies) the influence of climatic conditions and management practices on the annual C balance was only semi-quantitatively assessed. An extended period of EC measurements combined with modelling is required to more accurately quantify the effect of different climatic conditions on the annual C balance, and the influence of different management practices needs to be quantified using specifically designed studies (such as paired EC towers), so that practices which minimise C losses and maximise C sequestration can be identified.     

Biodecolorization and partial mineralization of Reactive Black 5 by a strain of Rhodopseudomonas palustris

A strain of photosynthetic bacterium, Rhodopseudomonas palustris W1, isolated from a lab-scale anaerobic moving bed biofilm reactor (MBBR) treating textile e?uent was demonstrated to decolorize Reactive Black 5 (RB5) effciently under anaerobic condition. By a series of batch tests, the suitable conditions for RB5 decolorization were obtained, namely, pH < 10, light presence, glutamine or lactate as carbon source with concentration more than 500 mg/L when lactate is selected, NH4Cl as a nitrogen source with ...     

Land Area Eligible for Afforestation and Reforestation within the Clean Development Mechanism: A Global Analysis of the Impact of Forest Definition

Within the United Nations Framework Convention on Climate Change (UNFCCC) Kyoto Protocol, countries have significant latitude to define a forest. The most important parameter affecting area designated as forest is the minimum crown cover which can be set between 10 and 30%. The choice will have implications for the amount of land available in a country for afforestation and reforestation activities within the Clean Development Mechanism (CDM-AR). In this paper, we present an analysis of the regional differences in land availability for CDM-AR projects. We then examine how the choice of a high or low threshold value for crown cover will affect the area available for CDM activities and how the limitations imposed by this element of the definition compares to other factors that are likely to limit CDM activities. Results represent a global analysis that included all countries not included in Annex I of the Kyoto Protocol, and examined the effect on land availability of a range of crown cover thresholds ranging from 10–30%. Of the 140 Non-Annex One countries, 107 countries were found to have a potential for CDM-AR projects. Asia had the largest amount of combined area suitable for CDM-AR at the 10% crown cover threshold level. However, at 30%, South America had the greatest amount of land available, and a large change in available land area, which increased by almost five times compared to what was available at the 10% threshold. The area available in Africa increased by a factor of 5.5. Central America showed the largest increase, to almost 10 times more at the 30% threshold. By contrast, within Asia, the area increase was comparatively less, but still the area nearly doubled. Globally, a low threshold of 10% crown cover excluded almost 2/3 of the land identified that was eligible at 30%, over 5 million km². The spatial analyses showed not only the effects of the choice of the crown cover criterion, but also where the land was available for CDM activities within each country at different thresholds. Protected areas account for 10–20% of the CDM-AR eligible area in most countries.     

三江平原湿地土壤活性有机碳组分特征及其与土壤酶活性的关系

对三江平原3种主要类型天然湿地(毛苔草湿地、小叶章湿地、岛状林湿地)O-20cm土壤活性有机碳(土壤微生物量碳、土壤可溶性有机碳)特征进行了研究,分析了不同湿地的土壤活性有机碳与土壤总有机碳及酶活性间的关系.结果表明:不同类型湿地的土壤活性有机碳组分含量存在较大的差异,土壤活性有机碳、土壤总有机碳及土壤脲酶、蔗糖酶、淀粉酶、过氧化氢酶的变化趋势具有基本近似的特征.表现为毛苔草湿地>小叶章湿地>岛状林湿地;土壤微生物量碳、可溶性有机碳与土壤总有机碳和酶活性存在显著正相关关系,其中,酶活性与土壤微生物量碳相关性最为显著.另外.毛苔草湿地土壤MBC/SOC、DOC/SOC的比值低于其它2种类型湿地,表明毛苔草湿地生物活性有机碳库的周转速率低.淹水抑制了微生物和酶的分解作用,有利于土壤有机碳的累积.因此,沼泽湿地水文条件的变化将会对土壤碳累积与分解过程产生较大的影响.     

Review of greenhouse gas emissions from crop production systems and fertilizer management effects

Fertilizer nitrogen (N) use is expanding globally to satisfy food, fiber, and fuel demands of a growing world population. Fertilizer consumers are being asked to improve N use efficiency through better management in their fields, to protect water resources and to minimize greenhouse gas (GHG) emissions, while sustaining soil resources and providing a healthy economy. A review of the available science on the effects of N source, rate, timing, and placement, in combination with other cropping and tillage practices, on GHG emissions was conducted. Implementation of intensive crop management practices, using principles of ecological intensification to enhance efficient and effective nutrient uptake while achieving high yields, was identified as a principal way to achieve reductions in GHG emissions while meeting production demands. Many studies identified through the review involved measurements of GHG emissions over several weeks to a few months, which greatly limit the ability to accurately determine system-level management effects on net global warming potential. The current science indicates: (1) appropriate fertilizer N use helps increase biomass production necessary to help restore and maintain soil organic carbon (SOC) levels; (2) best management practices (BMPs) for fertilizer N play a large role in minimizing residual soil nitrate, which helps lower the risk of increased nitrous oxide (N₂O) emissions; (3) tillage practices that reduce soil disturbance and maintain crop residue on the soil surface can increase SOC levels, but usually only if crop productivity is maintained or increased; (4) differences among fertilizer N sources in N₂O emissions depend on site- and weather-specific conditions; and (5) intensive crop management systems do not necessarily increase GHG emissions per unit of crop or food production; they can help spare natural areas from conversion to cropland and allow conversion of selected lands to forests for GHG mitigation, while supplying the world's need for food, fiber, and biofuel. Transfer of the information to fertilizer dealers, crop advisers, farmers, and agricultural and environmental authorities should lead to increased implementation of fertilizer BMPs, and help to reduce confusion over the role of fertilizer N on cropping system emissions of GHGs. Gaps in scientific understanding were identified and will require the collaborative attention of agronomists, soil scientists, ecologists, and environmental authorities in serving the immediate and long-term interests of the human population.     

Farm soil carbon monitoring developments and land use change: unearthing relationships between paddock carbon stocks, monitoring technology and new market options in Western Australia

This research provides a synthesis of soil organic carbon (SOC) densities in a range of Australian soils and land use types to decrease uncertainties in agricultural soil carbon (C) sequestration investments. This work provides information on existing Australian C soil stocks, the relationships between SOC with various agricultural and forestry land use changes, and options available for agriculturalists to cultivate and safeguard their C stocks. This work also includes recent developments in C rights, soil C monitoring, and verification technologies and procedures now in use for C stock inventories. This review has a special focus on known changes in SOC stocks, technological and methodological developments in the agricultural region of southern Western Australia (WA).     

改善焦化废水生物脱氮效率的研究

采用SBR反应器对焦化废水进行生物脱氮处理时,存在NO2^--N的积累现象。通过控制pH和投加碳源来改善生物脱氮效率。结果表明,把反应器内pH水平控制在7．0-7．5时,反硝化速率最大。比较了在好氧阶段2和缺氧阶段2投加甲醇对脱氮效率的影响。在没有外加碳源的情况下,SBR反应器的脱氮效率平均为78．4％,在好氧阶段2投加甲醇时,反应器的脱氮效率平均为90．2％,在缺氧阶段2投加甲醇时,反应器的脱氮效率平均93．8％。在投加甲醇后脱氮效率比没有外加碳源时有明显的提高,通过调节pH值和投加碳源可明显增加脱氮效果。     

Water budget and the consequent duration of canopy carbon gain in a teak plantation in a dry tropical region: Analysis using a soil–plant–air continuum multilayer model

A soil–plant–air continuum multilayer model was used to numerically simulate canopy net assimilation (A_n), evapotranspiration (ET), and soil moisture in a deciduous teak plantation in a dry tropical climate of northern Thailand to examine the influence of soil drought on A_n. The timings of leaf flush and the end of the canopy duration period (CDP) were also investigated from the perspective of the temporal positive carbon gain. Two numerical experiments with different seasonal patterns of leaf area index (LAI) were carried out using above-canopy hydrometeorological data as input data. The first experiment involved seasonally varying LAI estimated based on time-series of radiative transmittance through the canopy, and the second experiment applied an annually constant LAI. The first simulation captured the measured seasonal changes in soil surface moisture; the simulated transpiration agreed with seasonal changes in heat pulse velocity, corresponding to the water use of individual trees, and the simulated A_n became slightly negative. However, in the second simulation, A_n became negative in the dry season because the decline in stomatal conductance due to severe soil drought limited the assimilation, and the simultaneous increase in leaf temperature increased dark respiration. Thus, these experiments revealed that the leaflessness in the dry season is reasonable for carbon gain and emphasized the unfavorable soil water status for carbon gain in the dry season. Examining the duration of positive A_n (DPA) in the second simulation showed that the start of the longest DPA (LDPA) in a year approached the timing of leaf flush in the teak plantation after the spring equinox. On the other hand, the end appeared earlier than that of all CDPs. This result is consistent with the sap flow stopping earlier than the complete leaf fall, implying that the carbon assimilation period ends before the completion of defoliation. The model sensitivity analysis in the second simulation suggests that a smaller LAI and slower maximum rate of carboxylation likely extend the LDPA because soil water from the surface to rooting depth is maintained longer at levels adequate for carbon gain by decreased canopy transpiration. The experiments also suggest that lower soil hydraulic conductivity and deeper rooting depth can postpone the end of the LDPA by increasing soil water retention and the soil water capacity, respectively.