Municipal Solid Waste Incineration Plant Research Articles

Developing Statistical Evaluation Model of Introduction Effect of MSW Thermal Recycling

For the effective utilization of municipal solid waste (MSW) through a thermal recycling, new technologies, such as an incineration plant using a Molten Carbonate Fuel Cell (MCFC), are being developed. The impact of new technologies should be evaluated statistically for various municipalities, so that the target of technological development or potential cost reduction due to the increased cumulative number of installed system can be discussed. For this purpose, we developed a model for discussing the impact of new technologies, where a statistical mesh data set was utilized to estimate the heat demand around the incineration plant. This paper examines a case study by using a developed model, where a conventional type and a MCFC type MSW incineration plant is compared in terms of the reduction in primary energy and the revenue by both electricity and heat supply. Based on the difference in annual revenue, we calculate the allowable investment in MCFC-type MSW incineration plant in addition to conventional plant. The results suggest that allowable investment can be about 30 millions yen/(t/day) in small municipalities, while it is only 10 millions yen/(t/day) in large municipalities. The sensitive analysis shows the model can be useful for discussing the difference of impact of material recycling of plastics on thermal recycling technologies.

Utilizing a database to interpret leaching characteristics of lead from bottom ashes of municipal solid waste incinerators

This study focuses on evaluation and quantification of factors affecting leachability of lead from bottom ashes of municipal solid waste incinerators (MSWI) by utilizing a database. The database, which was constructed with data collected from sources such as research papers, questionnaires and reports, consists of 1149 data sets on 508 MSWI plants. Factors chosen as affecting lead leachability included: pH in the leachate, loss on ignition of bottom ash, total content of lead, and content of main elements such as Fe, Mn, Si and Al. The lead leachability was reduced to a minimum at neutral pH, increased with increasing pH and, especially, showed an abrupt increase at pH levels above 12. The main factor controlling the pH of the leachate appeared to be leachable Ca 2+ originating from portlandite (Ca(OH) 2). Leaching concentration increased with increasing total contents of lead, and the relationship between leaching of lead and loss on ignition showed no distinct tendencies. The lead leaching ratio increased with decreasing total contents of Si, Mn and Fe. It is evident, therefore, that these numerous factors determine the leachability of lead in a simultaneous and complex manner.

Characteristics of air pollution control residues of MSW incineration plant in Shanghai

A unique type of waste – air pollution control (APC) residues – has received increasing attention in China since the first large-scale incinerator, Shanghai Yuqiao municipal solid waste (MSW) incineration plant, was installed in the country in 2002. The APC residues of this particular plant are similar to other residues that will be produced in other incineration plants under construction in China. This work examines for the first time the benchmark contaminants of APC residues from the Yuqiao Plant, with reference to soluble salts, heavy metals and dioxins. Experimental findings reveal that the residues contained a marked amount of soluble salts, of up to 17.4–21.9% (mostly chlorides), 0.98–1.5 ng TEQ/g ash of dioxins and various heavy metals. Lead is of particular concern, and requires stabilization before disposal. Heavy metal speciation schemes were implemented herein to determine the leaching characteristics. The correlation between the amounts of soluble salts or chemical speciation of the heavy metals and the leaching toxicity of these heavy metals in the residues is considered.

Polybrominated diphenyl ethers at a solid waste incineration plant II: atmospheric deposition

In the second of two papers, the atmospheric polybrominated diphenyl ethers (PBDE) deposition (wet and dry) at a municipal solid waste incineration (MSW) plant with electronics recycling is compared with that at an industrial urban reference site (URS) producing asphalt and concrete. Results of BDE209 and SigmaPBDE excluding BDE209 as representatives of new vs. old PBDEs are presented. Volume weighted mean SigmaPBDE and BDE209 concentrations at the MSW were 6.2 and 14.4 ng l(-1), and at the URS were 2.5 and 14.1 ng l(-1). Median SigmaPBDE and BDE209 deposition fluxes were 21.3, 63.8 and 7.0, 14.7 ng m(-2) day(-1) at the MSW and URS, respectively. The concentrations in precipitation and the deposition fluxes were significantly higher at the MSW compared to the URS. Measured total washout- ratios (W-T) were dependent on particle scavenging and the median WT for all congeners was 5.4x 10(5). Median dry particle deposition velocities ranged from 0.4 to 49 cm s(-1), depending on congener, showing that PBDEs are effectively removed from the atmosphere by particle deposition. PBDE fluxes increased at the reference site when winds were blowing from west south-west, i.e. from the direction of the MSW. PBDE deposition and washout ratios were not influenced by temperature or rain volume, suggesting a constant emission from the MSW regardless of weather conditions. Together with the results of paper I (Agrell et al., 2004, Atmospheric Environment, this issue) we therefore suggest that treatment of waste, e.g. electronics recycling, is more a source of old PBDEs to the environment, whereas the rather similar BDE209 concentrations at the two urban sites are more a result of proximity to potential diffuse sources. (C) 2004 Elsevier Ltd. All rights reserved. (Less)

Synthesis and efficiency of a new chemical fixation agent for stabilizing MSWI fly ash

In this study, a novel chemical fixation agent, colloidal aluminate oxide (CAO), has been synthesized and characterized in detail. CAO does not require cementitious additives, and can be used as a stabilizer of lead in the fly ash from municipal solid waste incineration (MSWI) plants. CAO reveals a high reduction ratio for the leachability of Pb of 94.8% when compared with three commercial fixation agents, MF-103, BTS-03 and POCAT, and two fine chemicals, ethylene diaminetetracetic acid (EDTA) and thiodiglycolic acid (TGA). A possible mechanism for CAO stabilization of lead is formulated based on the results of Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) spectra.

Analyses of incinerated ash of paper sludge: comparison with incinerated ash of municipal solid waste

Fourteen paper sludge samples were collected at seven representative pulp and paper mills in Japan, and were analyzed to obtain fundamental data on the reuse of paper sludge-incinerated ash as papermaking material. For comparison, incinerated ashes of municipal solid waste (MSW) were collected at MSW incineration plants in Tokyo, and analyzed by similar methods. Elementary and X-ray diffraction analyses revealed that the predominant elements in paper sludge samples are calcium, silicon, aluminum, and magnesium, which are derived from paper fillers, coating pigments, and coagulants used in papermaking and process effluent treatments. Similar results were also obtained for the MSW-incinerated ashes, indicating that major components in the collected MSW are paper-related materials. Incineration of paper sludge around 800°C is recommended in terms of high brightness of the incinerated ash, which has about 60% brightness. Calcium, silicon, and aluminum components in the paper sludge are fused or sintered by heating. Although paper-sludge-incinerated ashes have irregular shape and large particle size distributions, they may be used as papermaking materials after pulverization using a ball mill. The MSW-incinerated ashes have 5%–30% water-soluble fractions and low brightness, and thus incineration conditions must be changed to reuse the MSW-incinerated ash as a papermaking material.

Thermal treatment of stabilized air pollution control residues in a waste incinerator pilot plant. Part 1: Fate of elements and dioxins.

Air pollution control (APC) residues from municipal solid waste incinerator plants that are treated by means of the Ferrox process can be more safely disposed of due to reduction of soluble salts and stabilization of heavy metals in an iron oxide matrix. Further stabilization can be obtained by thermal treatment inside a combustion chamber of a municipal solid waste incinerator. The influence of the Ferrox products on the combustion process, the quality of the residues, and the partitioning of heavy metals between the various solids and the gas have been investigated in the Karlsruhe TAM-ARA pilot plant for waste incineration. During the experiments only few parameters were influenced. An increase in the SO2 concentration in the raw gas and slightly lower temperatures in the fuel bed could be observed compared with reference tests. Higher contents of Fe and volatile heavy metals such as Zn, Cd, Pb and partly Hg in the Ferrox products lead to increased concentration of these elements in the solid residues of the co-feeding tests. Neither the burnout nor the PCDD/F formation was altered by the addition of the Ferrox products. Co-feeding of treated APC residues seems to be a feasible approach for obtaining a single solid residue from waste incineration.

ごみ焼却施設における有機ハロゲン化合物のモニタリングについて(その他の環境関連技術(6),その他の環境関連技術)

Monitoring methods of dioxin or dioxin surrogate compounds for management of the emission in MSW (Municipal Solid Waste) incineration plant have been widely developed. In this study, OHCs(Organic Halogenated Compounds) ,which have been studied a possibility of dioxin surrogate compounds, were selected for the index of the emission. Field study was conducted at a MSW incineration plant. OHC concentrations and behavior in gas treatment process at a MSW incineration plant were investigated. OHC concentrations were reduced during gas treatment process, and the behavior showed high removal efficiency in ACR (Activated Carbon Reactor). Moreover the OHC behavior was similar to that of aromatic compounds (DXN, CBz, and CPh) in ACR.

Cutting Wastes from Municipal Solid Waste Incinerator Plants

Major problems facing modern society include the provision of energy and means for waste disposal with the minimum generation of pollution and secondary wastes. Sustainable cities require the recovery of energy from that fraction of waste that cannot be economically reused or recycled. With up to 28 million tonnes of municipal solid waste having an average energy value of 10,000 kJ kg-1 being generated in the UK annually, incineration of with energy recovery is seen as the best available option for the safe disposal of municipal waste. Current efficient waste management strategies are also aimed at reducing the amount of waste from municipal solid waste incinerator plants by processing ash from new plants to approach the target of zero net waste material output and reducing the pollutants in flue gases by end-of-pipe treatment. Although pollutants in flue gases can be reduced to practically any desired level, the economic and environmental costs should be justified. Our research activities at Sheffield University Waste Incineration Centre are focussed on cutting down the amount of waste produced by these plants in the form of ash, slag and air pollutants. Our aim is to develop efficient yet cost-effective waste, energy and pollution management strategies to assist the incineration industries to control and operate future energy plants in the most efficient way possible.

Formation and elimination of polychlorinated dibenzo- p -dioxins and polychlorinated dibenzofurans from municipal solid waste incinerators

The emissions of polychlorinated dibenzo- p -dioxins and polychlorinated dibenzofurans (PCDD/Fs) from incineration processes has become a major subject of considerable public and scientific concern in light of the evidence of their extreme toxicity. Efficient control of PCDD/F emissions from municipal solid waste (MSW) incineration plants requires fundamental knowledge of the pathways by which they are formed in these plants. Analytical tests conducted on several MSW incinerator residues confirmed that PCDD/Fs form in the heat recovery unit of the incinerator plant and are removed from the flue gas in the fabric filter. A mathematical model for predicting PCDD/F emissions from MSW incinerator plants was developed based on governing equations for their formation through the de novo synthesis mechanism in the post-combustion zone and their removal by the fabric filter. The PCDD/F concentrations and removal efficiencies computed using the mathematical model were also found to correspond remarkably well with plant test data.

A Novel Energy-Efficient Process Utilizing Regenerative Burners for the Detoxification of Fly Ash

During the last decade, the debate concerning incineration has focused mainly on potential risks from air emissions. Today, waste incineration will only gain full public acceptance if a high quality of ash residues can be guaranteed, particularly with respect to low levels of organic compounds such as polychlorinated dibenzo- p -dioxins and polychlorinated dibenzofurans (PCDD/Fs) and the high elution stability of toxic heavy metals. Conventional thermal treatment techniques such as vitrification have been used in the past for detoxification of the ash residues from incinerators, but at a significantly high cost due to the massive energy consumption of the process. This paper addresses the problem of safe disposal of millions of tonnes of contaminated fly ash produced each year by developing an economically viable energy efficient process that can convert this toxic material into a non-toxic material. The decontaminated material can then be safely land-filled or used in construction applications such as in road foundations. This approach is based on the fact that sintering of the ash residue results in destruction of its toxic organic components, and also fixation of its heavy metal content. The novelty of the process includes the integration of the sintering process with the concept of regenerative heating. This is a very energy-efficient concept that results in typical fuel savings of 65% in industrial furnaces. A fully operational ash detoxifying pilot plant with a throughput suitable for continuous treatment of fly ash generated by a typical municipal solid waste incinerator plant was constructed and operated. An extensive series of analytical tests were carried out on both the raw and thermally treated ash samples. The results obtained showed an achievement of up to 96% reduction in the heavy metal leaching potential in the sintered ash. The sintering process de-volatilized metals having a high vapour pressure and effectively trapped other heavy metals in oxide sinters/melts. The reduction in leaching potential can be largely attributed to the formation of these stable oxides. This finding was verified by computational analysis that showed that up to 99.9% of some metals were converted into metal oxides during the sintering process. Analysis of the sintered ash samples/pellets for PCDD/Fs using standardized methods with GS-MS/MS equipment showed a major reduction in PCDD/Fs concentrations to below the detectable limit of 0.1 pg g − 1. These results are exceptionally encouraging since they eliminate the concern over the safety and suitability of the sintered ash material/pellets for re-use. Each cyclone was designed to provide enough residence time for the ash particles to be heated up to the sintering temperature of 850°C. High temperature conditionswere maintained throughout the cyclone thus helping to avoid any re-formation of toxic organic compounds such as PCDD/Fs. Detailed analysis showed that the use of heat regeneration in our sintering process provided significant energy and economic savings of up to 50%.

The environmental fate of heavy metals arising from a MSW incineration plant

Pollutant fluxes from municipal solid waste (MSW) incinerators are of a certain concern, especially gaseous emissions from the stack, which constitute the major effluent from the plant. In this work, heavy metals in soil and vegetation sampled in different sites around the plant are compared with those found in the gaseous emissions from an incinerator: the suspected source and environmental matrices are observed together, in order to detect a possible relationship of cause and effect, using statistical methods. The incinerator examined, regarding dimension and technology, can be considered a typical Italian one. Heavy metal concentrations in soil and vegetation show a clear dependence on sampling year; similar behaviour can be found in emission fluxes referring to the same years. A dependence on the distance from the incinerator is also apparent. This study supplies a methodological approach that can be easily extended and applied to other suspected contamination sources.

Characterisation of bottom ash from municipal solid waste incineration in Catalonia

AbstractBottom ash from municipal solid waste incinerator plants in Catalonia was characterised to investigate some alternatives for its utilisation and their potential environmental impact. After a detailed chemical and mineralogical characterisation, physical and geotechnical properties were investigated. The study focused on the use of bottom ash as an aggregate substitute in pavement applications. The results show that this material may be successfully used as a compacted material in unbound road sub‐bases. According to Spanish Specifications for road construction, bottom ash complies with the technical requirements for sub‐bases. Data obtained from the leaching test satisfy the limit values established by Catalan Specifications for bottom ash utilisation. The use of bottom ash in the envisaged application should therefore not result in any environmental impact.© 2002 Society of Chemical Industry

高効率廃棄物発電プラント用新開発ステンレスチューブの実機における腐食特性

In order to realize the high-efficiency municipal solid waste(MSW)-to-power generation, an actual plant test of newly developed 20Ni-25Cr stainless steels added 3%Si together with the other conventional superheater tube materials was conducted in an MSW incineration plant in Tokyo. To confirm the effect of Si on high-temperature corrosion, the corrosion performance of developed steels was evaluated at 450 to 500°C for metal surface temperatures with considering the effect of flue gas and steam temperatures, through the detail investigation of various characteristics such as chemistry of the flue gas and ash deposits. The localized corrosion behavior of developed steels was also evaluated. It was proved that adding Si to 20Ni-25Cr stainless steels was also effective in this actual test, and developed steels had a good corrosion resistance rather superior to the conventional 20Ni-25Cr steels, probably due to the combined Cr and Si oxide layer. Moreover, corrosion behavior of welds, which exhibited different modes of corrosion failure, was also evaluated in terms of flue gas and steam temperatures.

Properties of Portland cement — stabilised MSWI fly ashes

In the present paper, the properties of Portland cement mixtures containing fly ashes (FA) collected at four different Italian municipal solid waste incineration (MSWI) plants were investigated. In particular, physical/mechanical characteristics (setting time, unconfined compressive strength (UCS) and shrinkage/expansion), as well as the acid neutralisation behaviour of the solidified products were considered. The FA composition, revealing enrichment in heavy metals, chlorides and sulphates, significantly altered the hydration behaviour of Portland cement. Consequently, for some of the investigated FA the maximum allowable content for the mixtures to achieve appreciable mechanical strength was 20 wt.%. Even at low FA dosages setting of cement was strongly delayed. In order to improve the properties of FA/cement mixtures, the use of additives was tested. Moreover, the acid neutralisation capacity (ANC) of the solidified products was evaluated in order to assess the ability of the matrix to resist acidification, and also to provide information on hydration progression, as well as on heavy metal release under different pH conditions. Comparison of the results from the present work with previous studies carried out on spiked mixtures lead to the conclusion that the mechanical properties of the stabilised FA could not be predicted based on the effect exerted by heavy metals and anions only, even when the dilution effect exerted on cement was taken into account. It was likely that a major role was also played by alkalis, which were present in the FA at much higher concentrations than in cement.

Sintering of MSW fly ash for reuse as a concrete aggregate

The sintering process of municipal solid waste (MSW) fly ash was investigated in order to manufacture sintered products for reuse as concrete aggregates. Four types of fly ash resulting from different Italian MSW incineration plants were tested in this study. A modification of the chemical composition of MSW fly ash — through a preliminary four-stage washing treatment of this material with water — was attempted to improve the chemical and mechanical characteristics of sintered products. The sintering treatment of untreated or washed fly ash was performed on cylindrical compact specimens (15 mm in diameter and 20 mm in height) at different compact pressures, sintering temperatures and times. The sintering process of untreated MSW fly ashes proved to be ineffective for manufacturing sintered products for reuse as a construction material, because of the adverse chemical characteristics of these fly ashes in terms of sulfate, chloride, and vitrifying oxide contents. A preliminary washing treatment of MSW fly ash with water greatly improved the chemical and mechanical characteristics of sintered products and, for all the types of fly ash tested, the sintered products satisfied the Italian requirements for normal weight aggregates for use in concretes having a specified strength not greater than 12 and 15 N/mm 2, when measured on cylindrical and cubic specimens, respectively. A compact pressure of 28 N/mm 2, a sintering temperature of 1140°C, and a sintering time of 60 min were the best operating conditions for manufacturing sintered products of washed MSW fly ash.

Characteristics and Properties of a Mixture Containing Fly Ash, Hydrated Lime, and an Organic Additive

Laboratory tests were carried out to obtain the "stabilization" of a fly ashes (FA) from municipal solid waste (MSW) incinerator plant, by addition of hydrated lime (20% w/w). Room-temperature granulation of the mix with different amounts of water, containing a polyaminoalkylolic additive, was carried out in a rotating drum. The presence of the organic additive in the mixes increases the compressive strength of the granules seasoned at the room temperature; moreover, the leachability of the chromium (VI) ion in acid medium (standard test) decreases. Cylindrical specimens were also tested for both mechanical strength and leaching behaviors. The inertization with hydrated lime and organic additive is simpler and less expensive than any other method so far investigated. The FA was characterized by means of X-ray diffraction, thermogravimetry, chemical, and particle-size analyses.

Contribution of stack gases and solid process wastes to the organic pollutant output of thermal waste treatment plants

Within the scope of fundamental investigations as well as individual research projects (W. Knorr, B. Hentschel, C. Marb, S. Schädel, M. Swerev, O. Vierle, J.-P. Lay, 1999. Rückstände aus der Müllverbrennung – Chancen für eine stoffliche Verwertung von Aschen und Schlacken. Initiativen zum Umweltschutz, 13 ed., Deutsche Bundesstiftung Umwelt, Erich Schmidt, Berlin), the Bavarian State Office for Environmental Protection performs emission measurements at thermal waste treatment plants to optimize operation, to accompany and support development of new technologies, and to study the effect of this kind of waste treatment technology on the environment. Based on recent studies (October 1995–July 1999) at six municipal solid waste incinerators (MSWI) in Bavaria all emission streams (solid and gas) are characterized with respect to organic pollutant contents and compared to the emissions of waste pyrolysis. The significant ranges of pollutant concentration as well as the specific congener patterns observed are similar for all MSWI, regardless of differences in technical design and waste input, but differ markedly from those of the pyrolysis products. The overall approach, including the sampling of all output streams and the determination of mass streams and volume flow rates, allows the calculation of the total output of different organic pollutants for waste incineration plants and to estimate the relative contribution of each of the emission streams to the total pollutant load. Removal efficiencies are also calculated for the air pollution control (APC) systems of the different MSWI plants.

215 触媒塔による排ガス中ダイオキシン類およびその他塩素化芳香族化合物の分解特性(排ガス・廃水(I))(廃棄物処理技術)

To reduce DXNs (PCDDs/DFs and Co-PCBs) in the flue gas of incinerators, a catalytic oxidation process has come into wide use because of its high effectiveness and easy operability. In this study, catalytic decomposition characteristics of various aromatic compounds, for example PolyChlorinated Naphthalenes (PCNs) and Polycyclic Aromatic Hydrocarbons (PAHs) as well as Chlorophenols (CPs) and Chloro-benzenes (CBzs), have been investigated comparing with DXNs, using V-W/Ti catalyst reactor in the flue gas from the municipal solid waste incinerator plant. It is found that 1) PCNs and CPs can be decomposed with high efficiency such as DXNs, 2) decomposition rate of PAHs is a little lower than DXNs, 3) CBzs is rather hard to be decomposed and 4) the activity of the catalyst has been kept after 18000hrs of exposure time in stearm of the flue gas.

High temperature co-treatment of bottom ash and stabilized fly ashes from waste incineration

Bottom ashes from two Danish municipal solid waste incineration plants were heated at 900°C with iron oxide stabilized air pollution control residues at actual mass flow ratios (9:1), simulating a treating method for the residues. The two residues were co-treated, producing one combined stream that may be utilized as a secondary road construction material. Scanning electron microscope analysis and grain size distribution analysis indicated that sintering of the particles did not occur. Batch leaching tests at liquid/solid 10 l/kg at a range of pH-values (6–10) quantified with respect to Cd, Cr and Pb revealed significant positive effects of co-heating the ashes, although Pb showed slightly increased leaching. At a liquid/solid ratio of 10 l/kg the leachate concentrations were still low at pH 7–10 and the release of Pb was, thus, not expected to limit the utilization of the mixed ashes. The process, thus, fixates the metals in the solid residues without altering the leaching properties of the bottom ash too significantly.