The Tropical Peatland Plantation-Carbon Assessment Tool: estimating CO2 emissions from tropical peat soils under plantations

Land use change on Indonesian peatlands contributes to global anthropogenic greenhouse gas (GHG) emissions. Accessible predictive tools are required to estimate likely soil carbon (C) losses and carbon dioxide (CO₂) emissions from peat soils under this land use change. Research and modelling efforts in tropical peatlands are limited, restricting the availability of data for complex soil model parameterisation and evaluation. The Tropical Peatland Plantation-Carbon Assessment Tool (TROPP-CAT) was developed to provide a user friendly tool to evaluate and predict soil C losses and CO₂ emissions from tropical peat soils. The tool requires simple input values to determine the rate of subsidence, of which the oxidising proportion results in CO₂ emissions. This paper describes the model structure and equations, and presents a number of evaluation and application runs. TROPP-CAT has been applied for both site specific and national level simulations, on existing oil palm and Acacia plantations, as well as on peat swamp forest sites to predict likely emissions from future land use change. Through an uncertainty and sensitivity analysis, literature reviews and comparison with other methods of estimating soil C losses, the paper identifies opportunities for future model development, bridging between different approaches to predicting CO₂ emissions from tropical peatlands under land use change. TROPP-CAT can be accessed online from www.redd-alert.eu in both English and Bahasa Indonesia.     

CO2 emissions from tropical drained peat in Sumatra,Indonesia

With the increasing use of tropical peatland for agricultural development, documentation of the rate of carbon dioxide (CO₂) emissions is becoming important for national greenhouse gas inventories. The objective of this study was to evaluate soil-surface CO₂ fluxes from drained peat under different land-use systems in Riau and Jambi Provinces, Sumatra, Indonesia. Increase of CO₂ concentration was tracked in measurement chambers using an Infrared Gas Analyzer (IRGA, LI-COR 820 model). The results showed that CO₂ flux under oil palm (Elaeis guineensis) plantations ranged from 34?±?16 and 45?±?25 Mg CO₂ ha^–1 year^–1 in two locations in Jambi province to 66?±?25 Mg CO₂ ha^–1 year^–1 for a site in Riau. For adjacent plots within 3.2 km in the Kampar Peninsula, Riau, CO₂ fluxes from an oil palm plantation, an Acacia plantation, a secondary forest and a rubber plantation were 66?±?25, 59?±?19, 61?±?25, 52?±?17 Mg ha^–1 year^–1, respectively, while on bare land sites it was between 56?±?30 and 67?±?24 Mg CO₂ ha^–1 year^–1, indicating no significant differences among the different land-use systems in the same landscape. Unexplained site variation seems to dominate over land use in influencing CO₂ flux. CO₂ fluxes varied with time of day (p?<?0.001) with the noon flux as the highest, suggesting an overestimate of the mean flux values with the absence of night-time measurements. In general, CO₂ flux increased with the depth of water table, suggesting the importance of keeping the peat as wet as possible.     

Life cycle assessment of hydrotreated vegetable oil from rape,oil palm and Jatropha

A life cycle assessment of hydrotreated vegetable oil (HVO) biofuel was performed. The study was commissioned by Volvo Technology Corporation and Volvo Penta Corporation as part of an effort to gain a better understanding of the environmental impact of potential future biobased liquid fuels for cars and trucks. The life cycle includes production of vegetable oil from rape, oil palm or Jatropha, transport of the oil to the production site, production of the HVO from the oil, and combustion of the HVO. The functional unit of the study is 1 kWh energy out from the engine of a heavy-duty truck and the environmental impact categories that are considered are global warming potential (GWP), acidification potential (AP), eutrophication potential (EP) and embedded fossil production energy. System expansion was used to take into account byproducts from activities in the systems; this choice was made partly to make this study comparable to results reported by other studies. The results show that HVO produced from palm oil combined with energy production from biogas produced from the palm oil mill effluent has the lowest environmental impact of the feedstocks investigated in this report. HVO has a significantly lower life cycle GWP than conventional diesel oil for all feedstocks investigated, and a GWP that is comparable to results for e.g. rape methyl ester reported in the literature. The results show that emissions from soil caused by microbial activities and leakage are the largest contributors to most environmental impact categories, which is supported also by other studies. Nitrous oxide emissions from soil account for more than half of the GWP of HVO. Nitrogen oxides and ammonia emissions from soil cause almost all of the life cycle EP of HVO and contribute significantly to the AP as well. The embedded fossil production energy was shown to be similar to results for e.g. rape methyl ester from other studies. A sensitivity analysis shows that variations in crop yield and in nitrous oxide emissions from microbial activities in soil can cause significant changes to the results.     

Turnover of dissolved organic carbon fuels nocturnal CO2 emissions from a headwater catchment reservoir, Southeastern China: Effects of ecosystem metabolism on source partitioning of CO2 emissions

Dam reservoirs in headwater catchments, as critical zones for their proximity to terrestrial sources, play important roles in dissolved organic carbon (DOC) cycling. However, the effects of ecosystem metabolism (EM) on DOC cycling are not well known. Here, in-situ diurnal and monthly observations were conducted to measure EM (including gross primary production (GPP), ecosystem respiration (ER) and heterotrophic respiration (HR)), DOC turnover and CO₂ emissions in a headwater catchment reservoir in Southeastern China in 2020. Our study showed the nocturnal CO₂ emission rate was about twice as high as in daytime, and was strongly driven by EM. The values for DOC turnover velocity ranged from 0.10 to 1.59 m/day, and the average DOC turnover rate was 0.13 day⁻¹, with the average removal efficiency of 12%. The contribution of respired DOC to daily CO₂ emissions ranged from 17% to 61%. The accumulated efficiencies were estimated to be 13% for the selected 15 reservoirs throughout the Changjiang River network, corresponding to about 0.34 Tg C/year of the respired DOC. The modified CO₂ flux was 0.75 Tg C/year, and respired DOC accounted for about 45% of total emitted CO₂ from the 15 larger reservoirs. Our research emphasizes the necessity of incorporating the effects of EM into studies of reservoir DOC removal and CO₂ emissions.     

Zero emissions of oil in water from offshore oil and gas installations: economic and environmental implications

‘Produced water’ is seawater mixed with hydrocarbons and derives from the extraction of oil and gas from under the seabed. Its discharge into the marine environment of the North Sea is strictly regulated. This paper discusses the environmental concerns associated with produced water, and the regulatory approach that is currently being taken to reduce produced water discharges into the sea. It is found that there is currently no evidence of harm to the marine environment from produced water, but a number of areas of uncertainty remain. A novel methodology, involving the analysis of material and energy flows, and their associated financial and environmental implications, is used to compare a number of different techniques of reducing these discharges. It is found that these techniques have significant environmental and financial implications. In the absence of evidence of actual environmental harm being caused by produced water, there are three possible precautionary approaches to its management and regulation. The approach that involves zero emissions of produced water implies a relatively high social valuation of the reduction in environmental risk that this achieves.     

Avoiding CO2 capture effort and cost for negative CO2 emissions using industrial waste in chemical-looping combustion/gasification of biomass

Chemical-looping combustion (CLC) is a combustion process with inherent separation of carbon dioxide (CO₂), which is achieved by oxidizing the fuel with a solid oxygen carrier rather than with air. As fuel and combustion air are never mixed, no gas separation is necessary and, consequently, there is no direct cost or energy penalty for the separation of gases. The most common form of design of chemical-looping combustion systems uses circulating fluidized beds, which is an established and widely spread technology. Experiments were conducted in two different laboratory-scale CLC reactors with continuous fuel feeding and nominal fuel inputs of 300 W_th and 10 kW_th, respectively. As an oxygen carrier material, ground steel converter slag from the Linz–Donawitz process was used. This material is the second largest flow in an integrated steel mill and it is available in huge quantities, for which there is currently limited demand. Steel converter slag consists mainly of oxides of calcium (Ca), magnesium (Mg), iron (Fe), silicon (Si), and manganese (Mn). In the 300 W unit, chemical-looping combustion experiments were conducted with model fuels syngas (50 vol% hydrogen (H₂) in carbon monoxide (CO)) and methane (CH₄) at varied reactor temperature, fuel input, and oxygen-carrier circulation. Further, the ability of the oxygen-carrier material to release oxygen to the gas phase was investigated. In the 10 kW unit, the fuels used for combustion tests were steam-exploded pellets and wood char. The purpose of these experiments was to study more realistic biomass fuels and to assess the lifetime of the slag when employed as oxygen carrier. In addition, chemical-looping gasification was investigated in the 10 kW unit using both steam-exploded pellets and regular wood pellets as fuels. In the 300 W unit, up to 99.9% of syngas conversion was achieved at 280 kg/MW_th and 900 °C, while the highest conversion achieved with methane was 60% at 280 kg/MW_th and 950 °C. The material’s ability to release oxygen to the gas phase, i.e., CLOU property, was developed during the initial hours with fuel operation and the activated material released 1–2 vol% of O₂ into a flow of argon between 850 and 950 °C. The material’s initial low density decreased somewhat during CLC operation. In the 10 kW, CO₂ yields of 75–82% were achieved with all three fuels tested in CLC conditions, while carbon leakage was very low in most cases, i.e., below 1%. With wood char as fuel, at a fuel input of 1.8 kW_th, a CO₂ yield of 92% could be achieved. The carbon fraction of C₂-species was usually below 2.5% and no C₃-species were detected. During chemical-looping gasification investigation a raw gas was produced that contained mostly H₂. The oxygen carrier lifetime was estimated to be about 110–170 h. However, due to its high availability and potentially low cost, this type of slag could be suitable for large-scale operation. The study also includes a discussion on the potential advantages of this technology over other technologies available for Bio-Energy Carbon Capture and Storage, BECCS. Furthermore, the paper calls for the use of adequate policy instruments to foster the development of this kind of technologies, with great potential for cost reduction but presently without commercial application because of lack of incentives.

     

Identification of main influencing factors of life cycle CO2 emissions from the integrated steelworks using sensitivity analysis

The amount of CO₂ emissions from steelworks accounts for a great share of the total CO₂ emissions from industry in China. Thus, reducing CO₂ emissions from steelworks is urgent for China's environmental protection and sustainable development. This study aims at identifying factors that influence CO₂ emissions from steelworks and proposing measures to reduce CO₂ emissions. The life cycle inventory (LCI) of iron and steel products implies the relationship between the CO₂ emissions of the steelworks and the input variables of the LCI. The Tornado Chart Tool is utilized to calculate the variation of CO₂ emissions caused by the change of each input variables of LCI. Then, mean sensitivity of each input variable is calculated and the ranking criterion developed is used to identify the main factors influencing the integrated steelworks. Subsequently, measures for reducing CO₂ emissions are proposed. The results indicate that the very important influencing factors of CO₂ emissions in steelworks are the CO₂ emission factor of Blast Furnace Gas (BFG), liquid steel unit consumption of continuous casting, continuous casting slab unit consumption of hot rolling and hot metal ratio of steel making. Consequently, many efficient measures for reducing CO₂ emissions have been proposed, such as removing CO₂ contained in BFG, decreasing the hot metal ratio of Basic Oxygen Furnace (BOF), recycling BFG, optimizing the products' structure, etc.     

Gridded estimates of CO2 emissions: uncertainty as a function of grid size

Mitigation and Adaptation Strategies for Global Change - A crucial aspect of constructing a gridded model of anthropogenic fossil fuel CO2 (FFCO2) emissions involves careful consideration of...     

喷流-移动床RDF热解燃烧时CO和NOX的释放特性

在下部为喷流-移动床热解室、上部为气相燃烧室的两段反应器内,利用实验室中制备的RDF对其在该反应器中进行部分燃烧部分热解然后气相燃烧特性进行了研究.RDF颗粒连续加入到热解室中,实现了在少量空气作用下部分燃烧并在较低温度下部分热解,热解气体与二次空气在上部燃烧室中高温燃烧.本文主要考察了热解室进风量(热解室温度)和二次风量(燃烧室温度)对NOX和CO释放特性的影响.     

Integration of biological method and membrane technology in treating palm oil mill effluent

Palm oil industry is the most important agro-industry in Malaysia, but its by-product-palm oil mill effluent (POME), posed a great threat to water environment. In the past decades, several treatment and disposal methods have been proposed and investigated to solve this problem. A two-stage pilot-scale plant was designed and constructed for POME treatment. Anaerobic digestion and aerobic biodegradation constituted the first biological stage, while ultrafiltration (UF) and reverse osmosis (RO) membrane units were combined as the second membrane separation stage. In the anaerobic expanded granular sludge bed (EGSB) reactor, about 43% organic matter in POME was converted into biogas, and COD reduction efficiency reached 93% and 22% in EGSB and the following aerobic reactor, respectively. With the treatment in the first biological stage, suspended solids and oil also decreased to a low degree. All these alleviated the membrane fouling and prolonged the membrane life. In the membrane process unit, almost all the suspended solids were captured by UF membranes, while RO membrane excluded most of the dissolved solids or inorganic salts from RO permeate. After the whole treatment processes, organic matter in POME expressed by BOD and COD was removed almost thoroughly. Suspended solids and color were not detectable in RO permeate any more, and mineral elements only existed in trace amount (except for K and Na). The high-quality effluent was crystal clear and could be used as the boiler feed water.     

Chemical looping with oxygen uncoupling: an advanced biomass combustion technology to avoid CO2 emissions

Mitigation and Adaptation Strategies for Global Change - Bioenergy with carbon dioxide (CO2) capture and storage (BECCS) technologies represent an interesting option to reach negative carbon...     

Pledges for climate mitigation: the effects of the Copenhagen accord on CO2 emissions and mitigation costs

The UN Framework Convention of Climate Change 15th Conference of the Parties Copenhagen Accord has been followed up by national pledges of greenhouse gas emissions reductions in the year 2020 without specifying measures to enforce actions. As a consequence, the capacity of parties to fulfil their obligations is of basic interest. This article outlines the effects of full compliance with pledges on greenhouse gas emissions, economic growth, and trade. The study is based on the global computable general equilibrium model global responses to anthropogenic changes in the environment (GRACE) distinguishing between fossil and non-fossil energy use. Global emissions from fossil fuels in 2020 turn out to be 15 % lower than in a business as usual scenario and 3 % below the global emissions from fossil fuels in 2005. China and India increase their emissions to 1 % and 5 % above business as usual levels in 2020. India and Russia increase their net export of steel corresponding to around 30 and 45 % of their production levels in 2020. In spite of some leakage of energy intensive production also to China, we find that structural change remains the dominant factor behind the rapid reduction of CO₂ emission intensity in China towards 2020.     

Affordable CO2 negative emission through hydrogen from biomass,ocean liming,and CO2 storage

Mitigation and Adaptation Strategies for Global Change - A new process to remove carbon dioxide (CO2) from the atmosphere, by combining commercial industrial technologies with ocean liming and CO2...     

Effects of different pretreatment methods on anaerobic mixed microflora for hydrogen production and COD reduction from palm oil mill effluent

Effects of different pretreatment methods on sludge inocula were evaluated with respect to hydrogen (H₂) production enhancement using palm oil mill effluent (POME) in a batch system. The experimental results showed that the pretreatment methods (chemical, acid, heat-shock, freezing and thawing, and base) at 35 °C and initial pH 5.5 had a positive influence on H₂ production yield and chemical oxygen demand (COD) removal efficiency during the fermentative H₂ production as compared to the control experiments (without pretreatment). Heat-shock pretreatment method was shown to be a simple and useful method for enhancing both H₂ producing and COD removal processes from POME with highest H₂ yield and COD removal efficiency at 0.41 mmol H₂/g COD and 86%, respectively.     

Greenhouse gas emissions from production and use of used cooking oil methyl ester as transport fuel in Thailand

Biodiesel, produced from various vegetable and/or animal oils, is one of the most promising alternative fuels for transportation in Thailand. Currently, the waste oils after use in cooking are not disposed adequately. Such oils could serve as a feedstock for biodiesel which would also address the waste disposal issue. This study compares the life cycle greenhouse gas (GHG) emissions from used cooking oil methyl ester (UCOME) and conventional diesel used in transport. The functional unit (FU) is 100 km transportation by light duty diesel vehicle (LDDV) under identical driving conditions. Life cycle GHG emissions from conventional diesel are about 32.57 kg CO₂-eq/FU whereas those from UCOME are 2.35 kg CO₂-eq/FU. The GHG emissions from the life cycle of UCOME are 93% less than those of conventional diesel production and use. Hence, a fuel switch from conventional diesel to UCOME will contribute greatly to a reduction in global warming potential. This will also support the Thai Government's policy to promote the use of indigenous and renewable sources for transportation fuels.     

Fairness aspects of linking the European emissions trading scheme under a long-term stabilization scenario for CO2 concentration

Climate equity is a crucial but difficult element in negotiations on a post-2012 climate regime. With respect to the trading of greenhouse gas emissions the equity aspect is considered in the Kyoto Protocol which demands that emissions trading should be supplemental to domestic abatement efforts. The question arises whether a linking of the European Union Emissions Trading Scheme (EU ETS) to non-EU emission trading schemes or the Clean Development Mechanism (CDM) could have an impact on principles of climate justice and thus potentially affect ongoing negotiations. In this study, we present the results of a three step analysis: In a first step, it estimates mid-term greenhouse gas emission entitlements for Annex B and Non-Annex B countries for the year 2020 which keep within reach a stabilization of the CO₂ concentration at 450 ppmv in the long-term. In the second step, the resulting emission entitlements are used as an input to an economic partial-equilibrium model in order to assess the shift of abatement efforts under different scenarios of linking the EU ETS. In a third step, we analyze the outcome of the economic model with respect to the future trend of European per capita emissions under the current EU ETS relative to different scenarios of linking the EU ETS. The model results indicate that European per capita emissions have to be reduced to a considerably smaller extent if a linking of the EU ETS is accompanied by an optimal design of the National Allocation Plans and if low-cost CO₂ permits became available via the CDM to a large extent.

Statistical optimization of adsorption processes for removal of 2,4-dichlorophenol by activated carbon derived from oil palm empty fruit bunches

The adsorption capacity of activated carbon produced from oil palm empty fruit bunches through removal of 2,4-dichlorophenol from aqueous solution was carried out in the laboratory. The activated carbon was produced by thermal activation of activation time with 30 min at 800℃. The adsorption process conditions were determined with the statistical optimization followed by central composite design. A developed polynomial model for operating conditions of adsorption process indicated that the optimum conditions for maximum adsorption of phenolic compound were： agitation rate of 100 r/min, contact time of 8 h, initial adsorbate concentration of 250 mg/L and pH 4. Adsorption isotherms were conducted to evaluate biosorption process. Langmuir isotherm was more favorable （R^2=0.93） for removal of 2,4-dichlorophenol by the activated carbon rather than Freundlich isotherm （R^2=0.88）.     

Significant influences of TiO2 crystal structures on NO2 and HONO emissions from the nitrates photolysis

The emissions of NO₂ and HONO from the KNO₃ photolysis in the presence of TiO₂ were measured using a round-shape reactor coupled to a NO_x analyzer. TiO₂ played important roles in the emission flux density of NO₂ (R_NO2) and HONO (R_HONO), depending on crystal structures and mass ratios of TiO₂. R_NO2 and R_HONO significantly decreased with increasing the rutile and anatase mass ratios from 0 to 8 and 0.5 wt.%, respectively. Nevertheless, with further increasing the anatase mass ratio to 8 wt.%, there was an increase in R_NO2 and R_HONO. R_NO2 on KNO₃/TiO₂/SiO₂ had positive correlation with the KNO₃ mass (1–20 wt.%), irradiation intensity (80–400 W/m²) and temperature (278–308 K), while it had the maximum value at the relative humidity (RH) of 55%. R_HONO on KNO₃/TiO₂/SiO₂ slightly varied with the KNO₃ mass and temperature, whereas it increased with the irradiation intensity and RH. In addition, the mechanism for NO₂ and HONO emissions from the nitrates photolysis and atmospheric implications were discussed.     

Decolorization of molasses melanoidins and palm oil mill effluent phenolic compounds by fermentative lactic acid bacteria

Lactobacillus plantarum SF5.6 is one of the lactic acid bacteria (LAB) that has the highest ability of molasses melanoidin (MM) decolorization among the 2114 strains of LAB. The strains were isolated from spoilage, pickle fruit and vegetable, soil and sludge from the wastewater treatment system by using technical step of enrichment, primary screening and secondary screening. This LAB strain SF5.6 was identified by 16S rDNA analysis and carbohydrate fermentation (API 50 CH). The top five LAB strains having high MM decolorization ( 55%), namely TBSF5.8-1, TBSF2.1-1, TBSF2.1, FF4A and SF5.6 were selected to determine the optimal condition. It was found that the temperature at 30°C under facultative conditions in GPY-MM medium (0.5% glucose, 0.1% peptone, 0.1% yeast extract, 0.1% sodium acetate, 0.05% MgSO4 and 0.005% MnCl2 in MM solution at pH 6) giving a high microbial growth and MM decolorization for all five strains. It was noticed that the decolorization of MM by LAB strains might be cell growth associated. L. plantarum SF5.6 grew rapidly within one day while the other strains took 2–3 days. This L. plantarum SF5.6 could rapidly decolorize MM to 60.91% without any lag phase, and it also had the ability to remove 34.00% phenolic compounds and 15.88% color from treated palm oil mill effluent.     

N20 emissions from forest and grassland soils in northern China

Nitrous oxide(N₂O)is a major trace gas in the atmosphere．It plays an important rote in global warming and zone depleting．In this paper,we set up a install to determine the N₂O emission flux from forest and grassland soil．We observed an interesting phenomenon：in our sampling sites,the soil always acts as a source of N₂O,but sometimes it acts as a sink when the temperature is lower than 15℃．