冷凝水回流对堆肥腐熟度和污染气体排放影响

为探究堆肥过程中高温水蒸气携带的冷凝水回流对腐熟度及温室气体排放的影响,本文以猪粪和厨余垃圾为堆肥原料,在60L密闭好氧堆肥反应器中进行48d的高温好氧堆肥实验.结果表明,堆肥高温期产生的饱和水蒸汽因发酵罐封闭体系不能及时排出,会在发酵罐壁形成冷凝水回流入堆体中,整个堆肥过程冷凝水产率为物料湿重的18%.此外,回流冷凝水中主要成分为NH₄⁺-N(11.40g/L)、溶解性有机碳(6.3g/L)以及无机盐离子,具有较高的EC值(41.05mS/cm)和pH值(9.22),而较高的NH₄⁺-N含量使冷凝水回流处理的堆肥产品种子发芽指数(GI)略达到腐熟(71.4%),与排出处理相比GI下降了25.5%.同时,冷凝水回流使NH₃和CH₄排放量分别增加了55.2%的60.2%,但是CO₂和N₂O排放量分别降低了16.8%的34.8%.研究表明,冷凝水回流可降低17.8%总温室效应.本文建议堆肥过程将高温水蒸气冷凝排出,一...     

Effect of aeration rate on composting of penicillin mycelial dreg

Pilot scale experiments with forced aeration were conducted to estimate effects of aeration rates on the performance of composting penicillin mycelial dreg using sewage sludge as inoculation. Three aeration rates of 0.15, 0.50 and 0.90 L/(min·kg) organic matter(OM) were examined. The principal physicochemical parameters were monitored during the 32 day composting period. Results showed that the higher aeration rate of 0.90 L/(min·kg) did not corresponded to a longer thermophilic duration and higher rates of OM degradation;but the lower aeration rate of 0.15 L/(min·kg) did induce an accumulation of NH+4-N contents due to the inhibition of nitrification. On the other hand, aeration rate has little effect on degradation of penicillin. The results show that the longest phase of thermophilic temperatures ≥ 55°C, the maximum NO-3-N content and seed germination, and the minimum C/N ratio were obtained with 0.50 L/(min·kg) OM. Therefore, aeration rates of0.50 L/(min·kg) OM can be recommended for composting penicillin mycelial dreg.     

双氰胺、氢醌与含磷添加剂联合使用对堆肥温室气体排放的影响

为实现堆肥过程N2O、CH4和NH3的同步减排,在双氰胺和氢醌的基础上进一步研究磷石膏和过磷酸钙添加对猪粪堆肥温室气体和NH3排放的影响.以猪粪和玉米秸秆为堆肥原料,设置3个堆肥处理:只添加双氰胺和氢醌(HD)、添加双氰胺、氢醌和磷石膏(HD+P)和添加双氰胺、氢醌和过磷酸钙(HD+S),在60L的发酵罐中进行40d的...     

通风速率对厌氧残余物沼渣堆肥的影响

以牛粪发酵残余物沼渣为原料,设置不同的通风速率进行堆肥,堆体的通风速率分别是0.2,0.5,0.8L/（min·kg OM）,分析堆肥20d过程中物理、化学和腐熟变化的特征,探讨不同通风速率对堆肥特性的影响.结果表明,通风速率为0.2,0.5L/（min·kg OM）的堆体维持高温阶段的时间为5d,而通风速率为0.8L/（min·kg OM）堆体维持高温阶段时间为4d;各堆体OM分解率分别是28.2%,32.9%,30.5%;通风速率对终产品pH值、电导率（EC）影响不大,pH值均能满足堆肥最优pH值,EC均未超过4mS/cm;通风速率为0.2L/（min·kg OM）的堆体终产品的NH₄⁺-N含量超过400mg/kg,各堆体终产品NO₃^--N的含量分别是2545,3146,2735mg/kg;各堆体终产品C/N分别是16.5,14.1,15.6;各堆体终产品GI值分别是92.2%,96.6%,82.7%.通风速率为0.5L/（min·kg OM）堆体E465/E665（E₄/E₆）最小,其腐殖化程度最高.综合分析,0.5L/（min·kg OM）是沼渣堆肥最为合适的通风速率.     

Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting

Gaseous emission (N₂O, CH₄ and NH₃) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of CO₂ and 0.8% to 7.5% of TOC emitted as CH₄. Most of the nitrogen was lost in the form of NH₃, which account for 9.6% to 32.4% of initial nitrogen. N₂O was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could affect the NH₃ (p = 0.0189), CH₄ (p = 0.0113) and N₂O (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH₄ emission but increase the NH₃ and N₂O losses. C/N ratio could affect the NH₃ (p = 0.0442) and CH₄ (p = 0.0246) emissions significantly, but not the N₂O. Lower C/N ratio caused higher NH₃ and CH₄ emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio.     

Assessments on emergy and greenhouse gas emissions of internal combustion engine automobiles and electric automobiles in the USA

Increasing energy consumption in the transportation sector results in challenging greenhouse gas (GHG) emissions and environmental problems. This paper involved integrated assessments on GHG emissions and emergy of the life cycle for the internal combustion engine (ICE) and electric automobiles in the USA over the entire assumed fifteen-year lifetime. The hotspots of GHG emissions as well as emergy indices for the major processes of automobile life cycle within the defined system boundaries have been investigated. The potential strategies for reducing GHG emissions and emergy in the life cycle of both ICE and electric automobiles were further proposed. Based on the current results, the total GHG emissions from the life cycle of ICE automobiles are 4.48E + 07 kg CO₂-e which is 320 times higher than that of the electric automobiles. The hotspot area of the GHG emissions from ICE and electric automobiles are operation phase and manufacturing process, respectively. Interesting results were observed that comparable total emergy of the ICE automobiles and electric automobiles have been calculated which were 1.54E + 17 and 2.20E + 17 sej, respectively. Analysis on emergy index evidenced a better environmental sustainability of electric automobiles than ICE automobiles over the life cycle due to its higher ESI. To the authors’ knowledge, it is the first time to integrate the analysis of GHG emissions together with emergy in industrial area of automobile engineering. It is expected that the integration of emergy and GHG emissions analysis may provide a comprehensive perspective on eco-industrial sustainability of automobile engineering.     

黄土及其他添加物对猪粪贮存过程氨气和温室气体排放的影响

畜禽粪肥在贮存阶段养分损失严重,是CO_2、CH_4、NH_3和N_2O等大气污染物的重要排放来源.本文采用室内培养方法,研究了添加黄土、秸秆、生物炭和膨润土对猪粪贮存过程中氨气及温室气体排放的影响.结果表明,添加10%用量的生物炭和膨润土处理的CO_2累积排放量与不添加任何添加物的猪粪对照相比分别降低了15.4%和20.9%,N_2O累积排放量分别降低了19.8%和37.6%.添加膨润土处理的NH_3损失量显著增加,但添加生物炭和膨润土处理的综合温室效应与猪粪对照相比均显著降低.添加10%秸秆处理的CH_4和NH_3累积排放量分别较猪粪对照降低了56.8%和95.8%,但其综合温室效应与对照相比差异不显著.模拟黄土垫圈过程添加黄土处理的氨气及温室气体累积排放量均显著降低,综合温室效应显著低于其他处理(p0.05).可见,黄土垫圈是保蓄粪肥碳、氮养分的有效措施,猪粪贮存阶段添加少量生物炭、膨润土对于减少粪肥综合温室效应具有积极作用.     

Assessing the potential for greenhouse gas mitigation in intensively managed annual cropping systems at the regional scale

We predicted changes in yields and direct net soil greenhouse gas (GHG) fluxes from converting conventional to alternative management practices across one of the world's most productive agricultural regions, the Central Valley of California, using the DAYCENT model. Alternative practices included conservation tillage, winter cover cropping, manure application, a 25% reduction in N fertilizer input and combinations of these. Alternative practices were evaluated for all unique combinations of crop rotation, climate, and soil types for the period 1997-2006. The crops included were alfalfa, corn, cotton, melon, safflower, sunflower, tomato, and wheat. Our predictions indicate that, adopting alternative management practices would decrease yields up to 5%. Changes in modeled SOC and net soil GHG fluxes corresponded to values reported in the literature. Average potential reductions of net soil GHG fluxes with alternative practices ranged from −0.7 to −3.3 Mg CO₂-eq ha⁻¹ yr⁻¹ in the Sacramento Valley and −0.5 to −2.5 Mg CO₂-eq ha⁻¹ yr⁻¹ for the San Joaquin Valley. While adopting a single alternative practice led to modest net soil GHG flux reductions (on average −1 Mg CO₂-eq ha⁻¹ yr⁻¹), combining two or more of these practices led to greater decreases in net soil GHG fluxes of up to −3 Mg CO₂-eq ha⁻¹ yr⁻¹. At the regional scale, the combination of winter cover cropping with manure application was particularly efficient in reducing GHG emissions. However, GHG mitigation potentials were mostly non-permanent because 60-80% of the decreases in net soil GHG fluxes were attributed to increases in SOC, except for the reduced fertilizer input practice, where reductions were mainly attributed to decreased N₂O emissions. In conclusion, there are long-term GHG mitigation potentials within agriculture, but spatial and temporal aggregation will be necessary to reduce uncertainties around GHG emission reductions and the delivery risk of the associated C credits.     

Comparative lifecycle greenhouse gas emissions and their reduction potential for typical petrochemical enterprises in China

Petrochemical enterprises have become a major source of global greenhouse gas (GHG) emissions. Yet, due to the unavailability of basic data, there is still a lack of case studies to quantify GHG emissions and provide petrochemical enterprises with guidelines for implementing energy conservation and emission reduction strategies. Therefore, this study conducted a life cycle assessment (LCA) analysis to estimate the GHG emissions of four typical petrochemical enterprises in China, using first-hand data, to determine possible emission reduction measures. The analytical data revealed that Dushanzi Petrochemical (DSP) has the highest GHG emission intensity (1.17 tons CO₂e/ton), followed by Urumqi Petrochemical (UP) (1.08 tons CO₂e/ton), Dalian Petrochemical (DLP) (average 0.58 tons CO₂e/ton) and Karamay Petrochemical (KP) (average 0.50 tons CO₂e/ton) over the whole life cycle. At the same time, GHG emissions during fossil fuel combustion were the largest contributor to the whole life cycle, accounting for about 77.31%–94.27% of the total emissions. In the fossil-fuel combustion phase, DSP had the highest unit GHG emissions (1.20 tons CO₂e), followed by UP (0.89 tons CO₂e). In the industrial production phase, DLP had the highest unit GHG emissions (average 0.13 tons CO₂e/ton), followed by UP (0.10 tons CO₂e/ton). During the torch burning phase, torch burning under accident conditions was the main source of GHG emissions. It is worth noting that the CO₂ recovery stage has "negative value," indicating that it will bring some environmental benefits. Further scenario analysis shows that effective policies and advanced technologies can further reduce GHG emissions.     

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.     

Development of an eco-ideation tool to identify stepwise greenhouse gas emissions reduction options for consumer goods

Pressure on consumer goods manufacturers to develop new products with significantly less environmental impact is growing, through increased consumer awareness of environmental issues and governments setting ambitious emissions reductions targets. A strategic response to this pressure is to prepare a portfolio of innovative product ideas to meet a range of future emissions reductions targets. However, although extensive work exists on ideation (the generation of novel product ideas) and eco-design (design for reduced environmental impact), eco-ideation (generation of ideas that particularly aim to reduce environmental impacts) has had little attention. The challenge of eco-ideation is to release the creativity of a broad range of employees, only few of whom may be familiar with the drivers of environmental impact.This paper proposes a novel tool to facilitate the generation of radical product and process ideas giving step-change reductions in greenhouse gas emissions. The features of products and processes that drive greenhouse gas emissions across the product life cycle were characterized with a set of indicators. A simple visual tool was created to show these indicators on a sliding scale between best and worst imaginable performance. A leading question associated with each slider was designed to stimulate lower impact ideas. The tool was iteratively refined and simplified through structured testing with individuals from across a range of roles and differing knowledge of environmental impacts. The final eco-ideation tool used 14 scales, with leading questions for each scale developed to stimulate idea generation.The tool’s effectiveness was evaluated through use in a series of 15 individual workshops and compared with the outcomes of an equal number of conventional 12-person group-brainstorming sessions. The comparison suggests that using the simple tool generally leads to a wider range of more radical ideas than emerge from group brainstorming.     

生物质炭与强还原处理对退化设施蔬菜地土壤温室气体排放的影响

生物质炭和土壤强还原处理（Reductive Soil Disinfestation, RSD）可以有效地修复退化设施蔬菜地土壤,但2种修复技术联用对土壤温室气体（CO₂、N₂O和CH₄）排放的影响研究报道较少.本研究采用室内培养实验,设置未修复土壤（CK）、生物质炭修复（BC）、RSD修复（RSD）和BC与RSD联合修复（BC+RSD）4个处理,35℃条件下培养15 d,研究BC与RSD单独以及联合修复对退化设施蔬菜地土壤温室气体排放和综合温室效应（Global Warming Potential, GWP）的影响.结果表明,与对照CK相比,BC处理土壤N₂O排放量显著下降了50.0%,但CO₂排放量和GWP均显著增加（p<0.05）;RSD和BC+RSD处理土壤CO₂、N₂O、CH₄排放量和GWP均大幅度增加.但与RSD处理相比,BC+RSD处理土壤N₂O排放量和GWP分别下降了71.0%和30.0%.相关分析表明,土壤CO₂、N₂O、CH₄排放量和GWP与可溶性有机碳（DOC）和铵态氮（NH₄⁺-N）显著正相关,与pH和硝态氮（NO₃^--N）显著负相关.可见,生物质炭可以减少退化设施蔬菜地RSD修复引起的GWP.     

强还原与生物炭对土壤酶活性和温室气体排放的影响

本研究设置未修复对照(CK)、土壤强还原处理(RSD)、生物炭修复(BC)以及RSD与生物炭联合修复(RSD+BC),采用培养实验对比研究不同修复处理对设施蔬菜地土壤酶活性和温室气体(CO2和N2O)排放的影响.结果表明:相比CK,RSD和RSD+BC处理显著提高了β-葡萄糖苷酶(βG)、纤维二糖水解酶(CBH)、过氧...     

Estimation of greenhouse gas emissions in China and the abatement measures

The major emission sources of carbon dioxide, methane, nitrous oxide and CFCs in China have been identified, and the emission trends has been estimated. Besides fossil fuel combustion, human respiration and biomass burning are important sources. Some feasible abatement measures on energy conservation, afforestation and biomass recycling have been discussed.     

氮肥管理措施对黑土玉米田温室气体排放的影响

采用静态箱-气相色谱法研究了不同氮肥管理措施(农民常规施肥、减氮20%、添加硝化抑制剂、施用控释肥)对黑土玉米田温室气体排放的影响.结果表明:黑土玉米田施肥(基肥和追肥)后1~3d出现N2O排放峰,施肥后16d内N2O排放量占生育期总排放量的28.8%~41.9%.减施氮肥20%显著降低土壤N2O排放,生育期内的N2O累积排放量减少了17.6%~46.1%,综合温室效应降低30.7%~67.8%,温室气体排放强度降低29.1%~67.0%.等氮量投入时,添加吡啶抑制剂土壤N2O排放量、综合温室效应和温室气体排放强度最低.玉米拔节~乳熟期出现了较强的土壤CO2排放,黑土玉米田是大气中CH4的一个较弱的“汇”,施氮和添加硝化抑制剂对黑土玉米田CO2排放和CH4吸收没有显著影响.添加硝化抑制剂和施用控释肥不影响玉米产量.在本试验条件下,减氮20%并添加吡啶抑制剂在保证玉米产量的同时, 减排增收效果优于其他施肥措施,适宜在黑土区玉米种植中推广使用.     

翻堆对强制通风静态垛混合堆肥过程及其理化性质的影响

为了了解翻堆对堆肥过程及理化性质的影响,开展了城市污泥、猪粪强制通风静态垛堆肥试验,试验共设4个处理,分别为升温期(3d)、高温期(10d)、降温期(20d)翻堆处理和不翻堆的对照处理.结果表明:翻堆处理能降低堆肥的挥发性固体含量,减轻其在堆体剖面的差异.升温期翻堆不利于堆体DOC含量的降低及腐熟度的提高.降温期翻堆会减小再次升温速率及其所达到的最高温度.升温期和降温期翻堆,虽然有利于堆体内湿度的均匀分布,但却会缩短高温持续时间、降低堆肥的减容率和脱水率.不同时期翻堆,堆肥的pH和EC有降低的趋势,但总体而言其影响并不是特别明显.在高温期翻堆的处理中高温期持续时间长达15d,堆体减容率高达29%,再次升温的升温速率和所达到的最高温度分别为4℃·d-1和60 5℃,且与其它处理相比,其堆肥的VS、DOC和湿度都较低,GI较大.由此试验表明,高温期翻堆的堆肥处理能提高强制通风静态垛堆肥的堆肥效率和质量.     

我国饮食结构变化对农业温室气体排放的影响

从食物消费端入手,研究饮食结构变化对农业温室气体排放的影响.研究显示我国食物消费呈现出动物性食物替代粮食消费的趋势,动物性食物的温室气体排放系数是植物性食物的7倍以上.1990~2010年人均食物消费相关的温室气体排放增长了39%,肉类消费已成为食物消费中最大的温室气体排放来源,且还将持续增长.当我国人均收入达到2010年美国水平时,世界平均肉类消费水平、高肉类消费水平、低肉类消费水平和营养均衡消费水平四种情景下,人均肉类消费的温室气体排放将比2010年分别增长47.8%、119.9%、4.8%、-29.6%.我国食物消费应当提倡在保障均衡营养摄入的前提下,适当减少肉类消费,达到温室气体减排、资源节约、污染减排的协同效应.     

曝停时间比对间歇曝气SBR短程硝化的影响

常温条件下(20~25℃),以生活污水为研究对象,采用间歇曝气序批式反应器1#、2#、3#,研究了不同曝停时间比(3:1、3:2、3:3)对亚硝酸盐氮积累、亚硝化稳定性、污染物去除效果及污泥沉降性能的影响.结果表明,在一定范围内,单元停曝时间所占比例越大,即曝停时间比越小越有利于亚硝酸盐氮的积累,启动速度越快,三者分别经35,30,29d实现了亚硝化的启动;稳定运行阶段,三者的氨氮容积去除负荷分别为0.57,0.48,0.40d-1,曝停时间比越小,则氨氮去除负荷越小,COD去除效果没有明显区别;1#运行至第82d时,亚硝化率呈现逐渐下降的趋势,2#、3#仍能稳定运行,因此曝停时间比越小,越有利于抑制NOB的增殖,维持亚硝化的稳定,且污泥沉降性能越好,越有利于抑制丝状菌污泥膨胀.     

通风速率对厨余垃圾堆肥NH3和H2S排放及腐熟度影响

为了减少厨余垃圾堆肥过程中NH3和H2S产生,该研究以通风速率0.16m3/h的纯厨余堆肥作为对照,以添加15%玉米秸秆(湿基)的厨余垃圾堆肥作为处理,并设置3个不同的通风速率(0.08、0.16和 0.24m3/h),研究通风速率对NH3和H2S排放及堆肥腐熟度的影响.结果表明:纯厨余垃圾堆肥总氮含量有所下降,添加秸秆后总氮量都有不同程度的提高,通风速率为0.16m3/h的处理效果最好,总氮含量可提高39.05%.与纯厨余堆肥相比,添加秸秆可减排14%~53% 的NH3 和67%~80%的H2S.随着通风速率的增加,NH3累计排放量呈对数增长趋势;H2S排放无明显规律,但过低和过高的通风速率,都会导致较高的H2S排放.堆肥结束后, 4个处理均可达到无害化标准和腐熟要求.综合NH3和H2S控制效果,厨余垃圾堆肥合适通风速率为0.16m3/h.     

浅层淹水条件下不同施肥处理对黑土温室气体排放的影响

以东北黑土区长期耕作土壤为对象,通过室内培养试验研究了浅层淹水条件下不同施肥处理对黑土温室气体排放的影响.结果表明,浅层淹水条件下,与不施肥对照处理相比,单施氮肥处理对土壤CO₂排放没有显著影响,氮肥配施猪粪或者秸秆则显著促进了CO₂的排放,使得CO₂排放速率提高了一个数量级,氮肥配施秸秆处理的CO₂排放量最高.浅层淹水条件下,与不施肥对照处理相比,施用氮肥显著促进了土壤N₂O的排放.而与单施氮肥处理相比,氮肥配施猪粪和秸秆则显著抑制了N₂O的排放,表现为土壤对N₂O的微量吸收,氮肥配施秸秆处理的N₂O吸收量相对较高.浅层淹水条件下施用氮肥抑制了土壤CH₄的排放,而与单施氮肥处理相比,氮肥配施猪粪或者秸秆则促进了土壤CH₄的排放.