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Thomas Hojlund Christensen - One of the best experts on this subject based on the ideXlab platform.
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life cycle assessment of the historical development of Air Pollution Control and energy recovery in waste incineration
Waste Management, 2010Co-Authors: Anders Damgaard, Christian Riber, Thilde Fruergaard, Tore Hulgaard, Thomas Hojlund ChristensenAbstract:Abstract Incineration of municipal solid waste is a debated waste management technology. In some countries it is the main waste management option whereas in other countries it has been disregarded. The main discussion point on waste incineration is the release of Air emissions from the combustion of the waste, but also the energy recovery efficiency has a large importance. The historical development of Air Pollution Control in waste incineration was studied through life-cycle-assessment modelling of eight different Air Pollution Control technologies. The results showed a drastic reduction in the release of Air emissions and consequently a significant reduction in the potential environmental impacts of waste incineration. Improvements of a factor 0.85–174 were obtained in the different impact potentials as technology developed from no emission Control at all, to the best available emission Control technologies of today (2010). The importance of efficient energy recovery was studied through seven different combinations of heat and electricity recovery, which were modelled to substitute energy produced from either coal or natural gas. The best Air Pollution Control technology was used at the incinerator. It was found that when substituting coal based energy production total net savings were obtained in both the standard and toxic impact categories. However, if the substituted energy production was based on natural gas, only the most efficient recovery options yielded net savings with respect to the standard impacts. With regards to the toxic impact categories, emissions from the waste incineration process were always larger than those from the avoided energy production based on natural gas. The results shows that the potential environmental impacts from Air emissions have decreased drastically during the last 35 years and that these impacts can be partly or fully offset by recovering energy which otherwise should have been produced from fossil fuels like coal or natural gas.
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long term leaching from mswi Air Pollution Control residues leaching characterization and modeling
Journal of Hazardous Materials, 2009Co-Authors: Jiri Hyks, Thomas Fruergaard Astrup, Thomas Hojlund ChristensenAbstract:Abstract Long-term leaching of Ca, Fe, Mg, K, Na, S, Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Mo, Sb, Si, Sn, Sr, Ti, V, P, Cl, and dissolved organic carbon from two different municipal solid waste incineration (MSWI) Air-Pollution-Control residues was monitored during 24 months of column percolation experiments; liquid-to-solid (L/S) ratios of 200–250 L/kg corresponding to more than 10,000 years in a conventional landfill were reached. Less than 2% of the initially present As, Cu, Pb, Zn, Cr, and Sb had leached during the course of the experiments. Concentrations of Cd, Fe, Mg, Hg, Mn, Ni, Co, Sn, Ti, and P were generally bellow 1 μg/L; overall less than 1% of their mass leached. Column leaching data were further used in a two-step geochemical modeling in PHREEQC in order to (i) identify solubility Controlling minerals and (ii) evaluate their interactions in a water-percolated column system over L/S of 250 L/kg. Adequate predictions of pH, alkalinity, and the leaching of Ca, S, Al, Si, Ba, and Zn were obtained in a simultaneous calculation. Also, it was suggested that removal of Ca and S together with depletion of several minerals apparently caused dissolution of ettringite-like phases. In turn, significant increase in leaching of oxyanions (especially Sb and Cr) was observed at late stage of leaching experiments.
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geochemical modeling of leaching from mswi Air Pollution Control residues
Environmental Science & Technology, 2006Co-Authors: Thomas Fruergaard Astrup, J J Dijkstra, Rob N J Comans, H A Van Der Sloot, Thomas Hojlund ChristensenAbstract:This paper provides an improved understanding of the leaching behavior of waste incineration Air-Pollution-Control (APC) residues in a long-term perspective. Leaching was investigated by a series of batch experiments reflecting leaching conditions after initial washout of highly soluble salts from residues. Leaching experiments were performed at a range of pH-values using carbonated and noncarbonated versions of two APC residues. The leaching data were evaluated by geochemical speciation modeling and discussed with respect to possible solubility Control. The leaching of major elements as well as trace elements was generally found to be strongly dependent on pH. As leaching characterization was performed in the absence of high salt levels, the presented results represent long-term leaching after initial washout from a disposal site, that is, liquid-to-solid ratios above 1−2 L/kg. The leaching of Al, Ba, Ca, Cr, Pb, S, Si, V, and Zn was found influenced by solubility Control from Al2O3, Al(OH)3, Ba(S,Cr)O4 ...
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assessment of long term leaching from waste incineration Air Pollution Control residues
Waste Management, 2006Co-Authors: Thomas Fruergaard Astrup, Hans Mosbaek, Thomas Hojlund ChristensenAbstract:Abstract Assessment of long-term leaching from MSWI Air-Pollution-Control (APC) residues is discussed with respect to use in environmental impact assessment, such as life-cycle assessment (LCA). A method was proposed for estimating leaching as a function of the liquid-to-solid (L/S) ratio in a long-term perspective (L/S 5000 l/kg). Data for changes in residue pH as a function of L/S was used in combination with pH dependent leaching data to predict leachate concentrations of Al, Ca, Cd, Ba, Mg, Ni, Pb, S, Pb, V and Zn as a function of L/S. Mass balance calculations were used to determine the element fractions leached with respect to L/S. The estimated long-term leaching from a semi-dry residue and a fly ash was compared with short-term leaching determined by batch tests at L/S 10 l/kg, both carbonated and non-carbonated versions of the residues were investigated. Generally, very high L/S ratios above 2000 l/kg were required to leach 20–30% of the solid contents. However, Ca and S were depleted at L/S 200–900 l/kg. The long-term leachate concentrations were found to either remain at the same level as the initial leaching determined by the L/S 10 batch test, or to significantly decrease compared with the initial leaching. Only Al and Zn were found to show higher leachate concentrations at L/S ratios above 3000–5000 l/kg. Carbonation generally prolonged the time needed for depletion from the solid residues; however, Ca and S were depleted faster than in the case of non-carbonated residues. This study shows that uncritical use of batch leaching data for assessing the potential leaching is highly problematic, and evaluations of residue disposal should include scenario specific quantification of the long-term leaching.
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Thermal Treatment of Stabilized Air Pollution Control Residues in a Waste Incinerator Pilot Plant. Part 2: Leaching Characteristics of Bottom Ashes
Waste Management & Research, 2004Co-Authors: Dorthe L. Baun, Thomas Hojlund Christensen, B. Bergfeldt, Jürgen Vehlow, E P B MogensenAbstract:With the perspective of generating only one solid residue from waste incineration, co-feeding of municipal solid waste and Air Pollution Control residues stabilized by the Ferrox process was investigated in the TAMARA pilot plant incinerator as described in Bergfeldt et al. (Waste Management Research, 22, 49-57, 2004). This paper reports on leaching from the combined bottom ashes. Batch leaching test, pH- static leaching tests, availability tests and column leaching tests were used to characterize the leaching properties. The leaching properties are key information in the context of reuse in construction or in landfilling of the combined residue. In general, the combined bottom ashes had leaching characteristics similar to the reference bottom ash, which contained no APC residue. However, As and Pb showed slightly elevated leaching from the combined bottom ashes, while Cr showed less leaching. The investigated combined bottom ashes had contents of metals comparable to what is expected at steady state afte...
Ligia Tirutabarna - One of the best experts on this subject based on the ideXlab platform.
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environmental behaviour of a construction made of a mixture of hydraulic binders and Air Pollution Control residues from municipal solid waste incineration part 2 simulation tests and validation of the source term modelling
Waste Management, 2000Co-Authors: Radu Barna, Z Rethy, Yves Perrodin, Pierre Moszkowicz, Ligia TirutabarnaAbstract:Abstract The reuse of waste materials requires the development of assessment methods for the long-term release of pollutants (source term) from wastes (or materials containing wastes) in contact with water. These methods depend on the scenario conditions: characteristics of the materials (especially physical structure and composition), contact with water… The scenario studied here is a water storage reservoir for fire extinguishing. The reservoir construction is made of a mixture of hydraulic binders and Air Pollution Control (APC) residues from municipal solid waste incinerator (MSWI). The modelling of the source term is performed in five steps ranging from the physico-chemical characterisation of the material to the validation of the proposed model by means of field simulation devices. This paper follows a first publication on source term modelling using laboratory tests which therefore concerns the comparison of the results obtained with the previously established model. The first laboratory scale simulation test aims at taking into account the role of the leachate carbonation in the leaching behaviour of the studied material. The results obtained show that Air carbonation of the leachate does not fundamentally change mass transfer mechanisms of easily soluble species (especially for alkaline metals). For these species, the use of the apparent diffusional model (model proposed in the previous paper) is, therefore, at first, a satisfactory solution for the prediction of long term leaching behaviour. The field scale test enables us to validate and calibrate the release model determined on a laboratory scale basis.
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environmental behaviour of a construction made of a mixture of hydraulic binders and Air Pollution Control residues from municipal solid waste incineration part 1 physico chemical characterisation and modelling of the source term
Waste Management, 2000Co-Authors: Radu Barna, Z Rethy, Yves Perrodin, Pierre Moszkowicz, Apichat Imyim, Ligia TirutabarnaAbstract:Abstract The reuse of waste materials requires the development of assessment methods for the long-term release of pollutants (source term) from wastes (or materials containing wastes) in contact with water. These methods depend on the scenario conditions: characteristics of the materials (especially physical structure and composition), contact with water. The scenario studied here is a water storage reservoir for fire fighting. The reservoir construction is made of a mixture of hydraulic binders and Air Pollution Control (APC) residues from a municipal solid waste incinerator (MSWI). The modelling of the source term is performed in 5 steps ranging from the physico-chemical characterisation of the material to the validation of the proposed model by means of field simulation devices. This article presents the first steps of the methodology: physico-chemical characterisation of the source term, identification of the main transfer mechanisms and laboratory scale modelling of the source term. During the physico-chemical characterisation, it has been shown that the solidified waste shows a high basic capacity and that a relative decrease in pH during leaching favours retention of the main pollutants. During the first leaching sequences, the dynamic leaching tests show that the release of pollutants such as cadmium, arsenic, zinc and lead is extremely low but that the release of alkaline species (sodium and potassium) and chloride is very high from the beginning, whereas the release of calcium remains very high even after 3600 h of leaching. Identification of the main transfer mechanisms concludes that the release of soluble pollutants is the combined result of diffusional transfer of pollutants in the solution and the physico-chemical specificity of the species. The modelling based on these features enables a good simulation of the release but reveals a deviation from the experimental results after 500 h for alkaline species and 1000 h for Ca and Cl leaching. However, this deviation only appears after release of the major part of these elements.
Takayuki Shimaoka - One of the best experts on this subject based on the ideXlab platform.
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impact of secondary generated minerals on toxic element immobilization for Air Pollution Control fly ash of a municipal solid waste incinerator
Environmental Science and Pollution Research, 2018Co-Authors: Takayuki Shimaoka, Hiroki Kitamura, Astryd Viandila Dahlan, Yu Tian, Takashi Yamamoto, Fumitake TakahashiAbstract:Impacts of secondary generated minerals on mineralogical and physical immobilization of toxic elements were investigated for chelate-treated Air Pollution Control (APC) fly ash of a municipal solid waste incinerator. Scanning electron microscope (SEM) observation showed that ettringite was generated after the moistening treatment with/without chelate. Although ettringite can incorporate toxic elements into its structure, elemental analysis by energy dispersive X-ray could not find concentrated points of toxic elements in ettringite structure. This implies that mineralogical immobilization of toxic element by the encapsulation to ettringite structure seems to be limited. Physical immobilization was also investigated by SEM observation of the same APC fly ash particles before and after the moistening treatment. The transfer of soluble elements was inhibited only when insoluble minerals such as gypsum were generated and covered the surface of fly ash particles. Neoformed insoluble minerals prevented soluble elements from leaching and transfer. However, such physical immobilization seems to be limited because insoluble mineral formation with surface coverage was monitored only one time of more than 20 observations. Although uncertainty owing to limited samples with limited observations should be considered, this study concludes that mineralogical and physical immobilization of toxic elements by secondary minerals is limited although secondary minerals are always generated on the surface of APC fly ash particles during chelate treatment.
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Statistical estimate of mercury removal efficiencies for Air Pollution Control devices of municipal solid waste incinerators.
The Science of the total environment, 2010Co-Authors: Fumitake Takahashi, Akiko Kida, Takayuki ShimaokaAbstract:Abstract Although representative removal efficiencies of gaseous mercury for Air Pollution Control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin Control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86 Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories.
Renato Baciocchi - One of the best experts on this subject based on the ideXlab platform.
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performance of a biogas upgrading process based on alkali absorption with regeneration using Air Pollution Control residues
Waste Management, 2013Co-Authors: Renato Baciocchi, Ennio Antonio Carnevale, G Costa, R Gavasci, Lidia Lombardi, Tommaso Olivieri, Laura Zanchi, Daniela ZingarettiAbstract:This work analyzes the performance of an innovative biogas upgrading method, Alkali absorption with Regeneration (AwR) that employs industrial residues and allows to permanently store the separated CO2. This process consists in a first stage in which CO2 is removed from the biogas by means of chemical absorption with KOH or NaOH solutions followed by a second stage in which the spent absorption solution is contacted with waste incineration Air Pollution Control (APC) residues. The latter reaction leads to the regeneration of the alkali reagent in the solution and to the precipitation of calcium carbonate and hence allows to reuse the regenerated solution in the absorption process and to permanently store the separated CO2 in solid form. In addition, the final solid product is characterized by an improved environmental behavior compared to the untreated residues. In this paper the results obtained by AwR tests carried out in purposely designed demonstrative units installed in a landfill site are presented and discussed with the aim of verifying the feasibility of this process at pilot-scale and of identifying the conditions that allow to achieve all of the goals targeted by the proposed treatment. Specifically, the CO2 removal efficiency achieved in the absorption stage, the yield of alkali regeneration and CO2 uptake resulting for the regeneration stage, as well as the leaching behavior of the solid product are analyzed as a function of the type and concentration of the alkali reagent employed for the absorption reaction.
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gas solid carbonation kinetics of Air Pollution Control residues for co2 storage
Chemical Engineering Journal, 2009Co-Authors: Valentina Prigiobbe, A Polettini, Renato BaciocchiAbstract:Abstract Gas–solid carbonation of Air Pollution Control (APC) residues is a CO 2 Capture and Storage (CCS) technology, where highly reactive Mg- or Ca-bearing materials adsorb CO 2 and form stable Mg- or Ca-carbonates. The carbonation kinetics of this reaction have been studied at different temperatures, CO 2 concentrations, and at atmospheric pressure in order to select the best operative conditions on the basis of CO 2 stored and reaction time. The samples were initially heated up to the operative conditions under argon atmosphere and then carbonated under a CO 2 –argon atmosphere. All carbonation kinetics were characterized by a rapid chemically Controlled reaction followed by a slower product layer diffusion-Controlled process. Maximum conversions between 60% and 80% were achieved, depending on the operative temperature and CO 2 concentration. Temperature did not notably affect the maximum conversion obtained in the experiments performed at temperatures equal or above 400 °C; the influence on the kinetics was masked by the change in initial composition due to dehydroxylation reaction and surface area while heating up to the operative temperature. A slight influence of CO 2 concentration on the kinetics was observed, whereas no influence on the maximum conversion was noticed. The obtained results suggest that the flue gases with 10 vol.% CO 2 concentration can be directly used to form stable carbonates, thus lumping capture and storage in a single step. The APC residues produced from the existing incineration plants would cover only 0.02–0.05% of the total CO 2 European storage capacity required to comply with the Kyoto protocol objectives. Nevertheless, the proposed carbonation route could be applied to other residues, such as Cement Kiln Dust, Paper mill residues and Stainless Steel Desulphurization slags, characterized by a high content of free calcium oxides and hydroxides, thus increasing the impact of this process option.
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co2 sequestration by direct gas solid carbonation of Air Pollution Control apc residues
Energy & Fuels, 2006Co-Authors: Renato Baciocchi, A Polettini, R Pomi, Valentina Prigiobbe, Viktoria Nikulshina Von Zedwitz, Aldo SteinfeldAbstract:Direct gas−solid carbonation of alkaline residues from Air Pollution Control (APC) systems was investigated with the aim of evaluating its contribution as a CO2 storage option as well as its effect on the properties of the residues, namely, the leaching behavior, which may affect the strategies for their disposal or reuse. APC residues from a medical solid-waste incinerator located in the vicinity of Rome, Italy, were selected for performing carbonation experiments with pure CO2 at reaction temperatures in the 200−500 °C range. The extent of calcium conversion to the carbonate form was found to be negligible below 300 °C, whereas the maximum conversion of 57% was already measured at 400 °C. This implies a storage capacity of 0.12 kg of CO2/kg of dry solid. Considering that the APC residues production in the EU25 equals 1260 kiloton/year, this translates in a CO2 storage potential for the European market of 0.15 megatons of CO2/year. On the basis of the ENV 12457-2 leaching test procedure performed after a...
Fumitake Takahashi - One of the best experts on this subject based on the ideXlab platform.
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impact of secondary generated minerals on toxic element immobilization for Air Pollution Control fly ash of a municipal solid waste incinerator
Environmental Science and Pollution Research, 2018Co-Authors: Takayuki Shimaoka, Hiroki Kitamura, Astryd Viandila Dahlan, Yu Tian, Takashi Yamamoto, Fumitake TakahashiAbstract:Impacts of secondary generated minerals on mineralogical and physical immobilization of toxic elements were investigated for chelate-treated Air Pollution Control (APC) fly ash of a municipal solid waste incinerator. Scanning electron microscope (SEM) observation showed that ettringite was generated after the moistening treatment with/without chelate. Although ettringite can incorporate toxic elements into its structure, elemental analysis by energy dispersive X-ray could not find concentrated points of toxic elements in ettringite structure. This implies that mineralogical immobilization of toxic element by the encapsulation to ettringite structure seems to be limited. Physical immobilization was also investigated by SEM observation of the same APC fly ash particles before and after the moistening treatment. The transfer of soluble elements was inhibited only when insoluble minerals such as gypsum were generated and covered the surface of fly ash particles. Neoformed insoluble minerals prevented soluble elements from leaching and transfer. However, such physical immobilization seems to be limited because insoluble mineral formation with surface coverage was monitored only one time of more than 20 observations. Although uncertainty owing to limited samples with limited observations should be considered, this study concludes that mineralogical and physical immobilization of toxic elements by secondary minerals is limited although secondary minerals are always generated on the surface of APC fly ash particles during chelate treatment.
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Statistical estimate of mercury removal efficiencies for Air Pollution Control devices of municipal solid waste incinerators.
The Science of the total environment, 2010Co-Authors: Fumitake Takahashi, Akiko Kida, Takayuki ShimaokaAbstract:Abstract Although representative removal efficiencies of gaseous mercury for Air Pollution Control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin Control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86 Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories.