Characterisation and management of incinerator wastes

Management of municipal and hospital wastes by means of incineration processes generates solid residues, such as bottom and fly ashes and air pollution control residues with high content of heavy metals, inorganic salts and other organic compounds. Characterisation of 24 ash samples, collected from four municipal solid waste incinerators (MSWI) and six hospital medical waste incinerators (HMWI) located in the Basque Country Region (Northern Spain), were carried out at the request of Spanish Regulations and European Economic Community guidelines.The ecotoxicity values, EC(50), of the TCLP leachates show a high variability ranging from 12,967 to 1,000,000mgl(-1) in MSWI samples and from 2917 to 333,150mgl(-1) in HMWI samples. Results from chemical characterisation of DIN 38414-S4 leachates show a high concentration of lead, sulphate and chloride in MSWI samples and chromium in HMWI samples.     

Efficient waste-to-energy system as a contribution to clean technologies

This paper deals with the problem of efficient energy utilization in the field of thermal processing of waste (waste-to-energy). An up-to-date incineration plant cannot be considered as only waste disposal facility. The waste combustion (incineration) processes are accompanied by release of large amount of energy, that shall be effectively utilized (e.g. steam production and its export to consumers, power generation, cogeneration). In addition to the main purpose of incineration, i.e. treating the specified amount of waste, waste-to-energy systems are able to some extent substitute conventional energy production plants fired by fossil fuel and thus to contribute to solving global environmental problems. For example, methodology presented in Reference Document on the Best Available Techniques for Waste Incineration (BREF) can be used for assessment of plant performance from the view of energy utilization. This approach is based on evaluation of criterion Plant Efficiency. An existing incineration plant has been evaluated and results are presented and discussed. In the future, it has been expected that evaluation like this will be obligatory for every plant. The arrival of more and more sweeping environmental limits represents a driving force for retrofit. At the same time maximum heat recovery and efficient energy utilization should be required. Influence of different operational modes (type of waste incinerated, combustion temperature, air-preheating etc.) and lay-out of heat recovery system (e.g. cogeneration) on plant performance has been investigated. A mathematical model based on combination of basic auxiliary operations and simple thermodynamic models of heat engines has been created with the aid of a specific computational tool. Its conception is based on both requirements and experience coming from industry. The most serious problem of effectively running incineration plants consists in economical utilization of energy produced. Examples of integration into existing energy systems are shown and discussed. An erratum to this article can be found at     

PCDD/F concentrations of agricultural soil in the vicinity of fluidized bed incinerators of co-firing MSW with coal in Hangzhou, China

The concentrations of 17PCDD/F congeners as well as tetra- to octa-homologues were determined in 33 soil samples collected within a radius of 7 km from a municipal solid waste (MSW) incineration plant that is equipped with three fluidized bed incinerators (FBIs) of co-firing MSW with coal in Hangzhou, China. The total PCDD/F concentrations ranged from 0.39 to 5.04 pg I-TEQ g(-1) (54-285 pg g(-1)), with an average and a median value of 1.22 and 0.84 pg I-TEQ g(-1) (105 and 86 pg g(-1)), respectively. A systematic decrease of PCDD/F levels was observed with the increasing distances and with the decreasing downwind frequencies from the plant. The comparisons of homologue and congener patterns and multivariate analysis of soil and flue gas samples strongly indicated that most of the soil samples were influenced by the FBIs. Apart from the incineration plant, historical PCDD/F emissions of hazardous waste incinerator (HWI) and motor vehicles as well as the application of 1,3,5-trichloro-2-(4-nitrophenoxy) benzene (CNP) seemed to play an important role in soil samples adjacent to these potential sources.     

Concentration and congener patterns of polychlorinated biphenyls in industrial and municipal waste incinerator flue gas, Korea

In the present study, individual PCB congeners were determined in the flue gases of 10 industrial and 5 municipal solid waste incinerators using HRGC/HRMS. The total PCBs concentration of all congeners (168 tetra to deca-chlorinated congeners) ranged from 26 to 343 ng/Nm(3), and from 36 to 1095 ng/Nm(3) in industrial waste incinerators (IWI) and municipal solid waste incinerators (MSWI), respectively. The total TEQ concentrations of PCBs, calculated using WHO-TEF values, varied from 0.001 to 0.55 ng-TEQ/Nm(3) and from 0.001 to 8.29 ng-TEQ/Nm(3) in the industrial waste incinerators and municipal solid waste incinerators, respectively. In all samples, the contribution of PCB 126 to total TEQ of PCBs was higher than 87%. The homologue pattern of PCBs in the incinerator flue gas samples was generally dominated by tetra- and penta-CBs. The distribution of other homologues was less than 15% in most of the incinerators. The fraction of co-PCBs against to total PCBs ranged from 1% to 19% and from 2% to 31% in IWI and MSWI flue gas samples. Results of the present study reveal that the presence of non-ortho PCB congeners in the flue gas originated form the combustion process.     

Comparison of the characteristics of bottom and fly ashes generated from various incineration processes

This study analyzed and compared the characteristics of bottom and fly ashes from three municipal solid waste incinerators (MSWIs) in Taiwan. Different incineration furnaces were investigated, including: (1) fluidized bed, (2) mass-burning, and (3) mass-burning linked rotary kiln. The particle size distribution, morphology, mineralogical and chemical composition, and leaching behavior of heavy metals of ash samples were evaluated. The results revealed that three types of incineration processes have different characteristic for ashes due to transportation and mixing system inside furnace. Particle size distribution indicated that 28.5% of MSWI-B bottom ash has lower than 180 microm and 61.2% of MSWI-A fly ash has larger than the 250 microm. The leaching concentration of Pb exceeded the regulatory level set by the Taiwan EPA in fly ashes from MSWI-B and MSWI-C, and thus must be considered hazardous wastes. Specifically, the leaching concentration of heavy metals of fly ashes from MSWI-A (fluidized bed incinerator) was lower than that of the others, and was corresponded to the regulatory levels. Therefore, a fluidized bed incineration process appears a potential of handling heavy metals for ashes. The result was also provided the valuable information for incinerator design and operation.     

Polychlorinated dibenzo-p-dioxin and dibenzofuran emissions from an industrial park clustered with metallurgical industries

Emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from an industrial park operated as Taiwan's center of metallurgical industries were investigated. The characteristics of mean PCDD/F I-TEQ concentrations, congener profiles and emission factors of each source were studied over samples of stack flue gases of individual sources. Different characteristics of congener profiles and large variations of emission factors of secondary aluminum smelters (ALSs) were observed. The mean emission factors of electric arc furnaces were comparable to those for ALSs and much greater than those of municipal solid waste incinerators and sinter plants, but still less than that of clinical waste incinerators. Annual PCDD/F emission contribution of each source was estimated, raising critical concerns over the overall PCDD/F emissions from metallurgical processes. The metallurgical industries altogether contributed approximately 98.1% of the total annual emissions, while waste incinerators only 1.9%. The contributions by sinter plants and metallurgical industries to the total annual emissions of the Park were much higher than the corresponding national averages of Taiwan. The combined dioxin emissions from the entire metallurgical processes and their controls should be seriously envisaged by industrial parks devoted to metal productions.     

Fluidized bed incinerator for medical waste that generates no residual dioxin: a mini-review

The advantages of medical waste incineration include the sterilization of bacteria, stabilization of chemical activity, and reduction in waste volume. During the incineration of medical waste, dioxin is generated owing to the high chlorine content. Based on previous research, a conventional fluidized bed combustor with a minimum retrofit to dispose of medical waste without residual dioxins is presented in this study. Coal or pyrite was added to inhibit dioxin formation in the combustion chamber. Fly ash and activated carbon which had adsorbed dioxin were pelletized with adhesive material, and the pelletized fly ash was then recycled to the incinerator for burning. The pelletized fly ash with adhesive material was finally discharged as bottom ash. Bottom ash constitutes the net output of the entire incineration system. and its dioxin content can be neglected. An incineration system that does not produce dioxin residue was achieved; however, a better formula for the pelletized fly ash is still required.

Title page (short abstract)

1. The emission of dioxin from medical waste incinerators can’t be eliminated by disabling PVC as a raw material of medical devices.

2. Based on the knowledge shown in the previous literature, an integrated fluidized bed incineration system without dioxin residual installed in a large hospital is proposed in this study.

3. There are many ways to reduce dioxin formation during the incineration process; however, conventional methods can’t eliminate the existence of dioxin in fly ash.

4. Pelletized fly ash recycled to the incinerator for re-burning and discharged in the form of bottom ash which is considered dioxin free.

     

废旧电路板非金属材料粉的能量利用实验与分析

为了实现废旧电路板非金属材料粉的资源化再利用,通过对废旧印刷电路板非金属材料的焚烧过程和机理进行研究与分析,采用流化床焚烧装置处理已经被破碎的废旧印刷电路板非金属材料粉,在提取其中的玻璃纤维的同时,使非金属粉中的树脂尽量充分焚烧,并且测量排气温度,从而确定废旧印刷电路板中树脂焚烧之后能量利用的可行性。结果表明:在600℃的床温下,废旧电路板非金属粉已经充分燃烧并能提取出高纯度的玻璃纤维,同时焚烧烟气中存在大量可利用的热能,且二英排放符合环保要求。     

废旧油墨的再生处理与利用的研究

目前废弃的油墨越来越多,对废弃物大多采取焚烧和掩埋的方式进行处理,对环境造成了极大的污染。采用对废旧油墨进行共沸蒸馏的方法,去除废弃油墨中大量的溶剂和水(润版液),经研磨、调色等加工处理,使废弃的油墨变为黑色油墨,进行再利用,并减少废弃物对环境的污染。     

The influences on leachate from landfill of incineration residuals by acid precipitation

Incineration of municipal solid wastes (MSW) is the main method of waste management in Taiwan. Although the incineration of MSW processes the solid wastes at 850-950 degrees C and destroys most of the organics, the content of incineration ashes is still a problem for landfill. Moreover, acid precipitation is much worse than before in Taiwan, especially in the northern areas. For instance, the occurrence probabilities of acid precipitation measured from 1991 to 1998 in Taipei increase from 73% to 85%. Therefore, it is more important to get a series of data that will help explore the influence of acid precipitation during disposal on characterization of pollutants than to analyze the ash properties after the incinerators have been constructed and regularly used. In this investigation, the disposal site of incineration ashes is simulated in laboratory by test columns. An irrigation experiment is taken to simulate the acid precipitation at room temperature. In order to explore the exact influence on leachate quality of the main chemical composition of acid precipitation, columns are migrated with different concentrations of sulfate in acid precipitation. This investigation showed that the sulfate concentration of acid precipitation has an increasing effect on the accumulative release of heavy metals, such as Zn, Pb and Cu, from leachate. The sulfate concentration of acid precipitation, however, will not influence the trend of chemical oxygen demand (COD), biochemical oxygen demand (BOD(5)) and total organic carbon (TOC) in the leachate release.     

Using biomass as an energy source with low CO2 emissions

This work deals with the carbon dioxide cycle and emissions from biomass incineration under a hydrogen production context. It is proposed to use the thermal energy obtained by biomass combustion to produce water steam, which afterwards would be converted into hydrogen by high temperature electrolysis (HTE). In France, the thermal energy potential from nonvalorised biomass reaches almost 6.5 Mtep. In this study, the potential avoided carbon emissions are quantified as well as the feasible hydrogen production capacity based on the steam supplied by the incineration units. Results show that carbon consumption in hydrogen production by steam methane reforming (SMR) or biomass incineration–HTE process is almost equivalent between both processes. However, the hydrogen produced by the biomass incineration–HTE process used to fuel vehicles, would lead to a decrease of 135 Mt of carbon from fossil origins yearly, in contrast to SMR.     

Characteristic of polychlorinated dibenzo-p-dioxins and dibenzofurans in fly ash from incinerators in china

Fly ash from municipal solid waste (MSW), medical waste (MW) and electrical power plant (EPP) incinerators were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The study showed that the PCDD/F levels in fly ash were EPP < MSW < MW. The homologue profiles of PCDD/Fs in fly ash produced from waste incinerators were similar. However, the homologue profiles of PCDD/Fs in fly ash from electrostatic precipitator (ESP) of electrical power plant were different from that from waste incinerator. The strong correlation was found between the concentration of 2,3,4,7,8-PeCDF and the I-TEQ value of fly ash regardless of the different fly ashes sources.     

Partitioning characteristics of targeted heavy metals in IZAYDAS hazardous waste incinerator

Partitioning of eight targeted heavy metals (Cr, Mn, Cu, Pb, Sn, Co, Ni and Zn) was carried out during five trial burns in Izmit hazardous and clinical waste incinerator (IZAYDAS). Metal contents of the original wastes and their concentration in the bottom ash (BA), fly ash (FA), filter cake (FC) and flue gas were determined. Partitioning behavior of metals during the two-stage incineration was evaluated with respect to physico-chemical properties of feed waste and metals, and the operational conditions. Results suggest that combustion temperatures and retention times are the dominant parameters determining the volatility of metals in the first combustion chamber. Targeted metals were generally partitioned in the rank of bottom ash, filter cake, fly ash and flue gas. High filter cake/fly ash ratios showed that high temperatures in the second stage increase both the formation of gaseous metallic compounds and the enrichment of metals in fine particles. Since ESP could not be effective in removing fine particles and volatilized metallic compounds, the necessity of an additional system that would remove heavy metals efficiently was emphasized for the modern incinerators.     

Mineralogical characterization of municipal solid waste incineration bottom ash with an emphasis on heavy metal-bearing phases

Municipal solid waste incineration (MSWI) bottom ash contains a considerable amount of heavy metals. The occurrence and uneven distribution of these heavy metals in bottom ash can increase the complexity of such residues in terms of long-term behavior upon landfilling or recycling. Bottom ashes sampled from three stoker-type incinerators in Japan were analyzed in this paper. This study presents detailed information on the mineralogical characterization of bottom ash constituents and the weathering behavior of these constituents by means of optical microscopy and scanning electron microscopy. It was revealed that bottom ash mainly consists of assorted silicate-based glass phases (48-54 wt% of ash) and mineral phases including melilites, pseudowollastonite, spinels, and metallic inclusions (Fe-P, Fe-S, Fe-Cu, Cu-Sn, Cu-Zn, Cu-S, and Cu-Pb dominated phases), as melt products formed during the incineration process. The compounds embedded in the glass matrix, e.g. spinels and metallic inclusions, played the most important role in concentration of heavy metals (Pb, Zn, Cu, Cr, Mn, Ni, etc.). Other phases such as refractory minerals and ceramics, frequently found in ash, were of less significance in terms of their influence on the involvement of heavy metals. Analysis of lab-scale artificially weathered and 10-year landfilled bottom ash samples revealed that secondary mineralization/alteration of the bottom ash constituents principally carbonation and glass evolution substantially decreased the potential risk of the heavy metals to the surrounding environment.     

Application of fuzzy logic for evaluation of the level of social acceptance of waste treatment

The social aspect is very important in sustainability assessment of waste treatment technique, as well as making decision on their application and planning. In recent years, it is becoming evident that a waste treatment technique, which ignores social aspects, is doomed to failure. The most commonly used social indicators are: number of jobs created, level of social acceptance, public knowledge, public health etc. The most of them are qualitative and measuring the sustainability and quantifying the social dimension of sustainability are difficult tasks. This paper presents the application of fuzzy logic for evaluating the social indicator—level of social acceptance. The fuzzy set theory and fuzzy logic were used to develop a model for the evaluation of level of social acceptance, due to the lack of data, uncertainties, and qualitative character of indicators and also to provide effective way to include knowledge and gained experience on the process. A questionnaire was applied as instrument for data collection. The fuzzy model was verified using the city of Ni? as a case study. The results obtained using the developed fuzzy model, shows that the highest level of social acceptance in the city of Ni? is for recycling (57.47 %) and the lowest level of social acceptance is for incineration (17.74 %). The presented study suggests an innovative methodology for evaluation of level of social acceptance of certain waste treatment based on fuzzy logic approach and can be used for ranking of waste management scenarios in the sustainability assessment.     

Application of methods (sequential extraction procedures and high-pressure digestion method) to fly ash particles to determine the element constituents: a case study for BCR 176

Sequential extraction procedures and the high-pressure digestion method were selected to determine the element constituents of fly ash samples. Sequential extraction is one of the most useful methods used to measure the various elements from municipal solid waste incineration ash and contaminated soils. The extract from each step is analyzed using various techniques and equipment, and the results are then evaluated. In this work, a six-step extraction procedure modified from that of Tessier et al. and Wang et al. was performed and applied to the certified reference material BCR 176 (city waste incineration ash). Analyses were carried out by various techniques such as inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma-mass spectrometry (ICP-MS), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), and X-ray powder diffraction (XRPD) to evaluate the characteristics of fly ash. The extraction efficiency of many elements was higher than 80%, and the relative standard deviations (RSD) for recovery of most elements were within 10%. In addition, an H(2)O(2)+HNO(3)+HF mixed acid digestion solution processed using a low-temperature evaporation procedure was selected as the optimal process for fly ash digestion. The results of this work provide information on the chemical composition, distribution, and potential mobility of the investigated elements.     

国内外生活垃圾焚烧发电技术进展

随着人们对环境方面要求的日益增长,垃圾合理处理在践行绿色发展理念和推动生态文明建设进程中发挥着越来越重要的作用。生活垃圾焚烧发电技术作为固废资源利用的一种方法,如今已经演变成为一种成熟的资源利用技术。分别从垃圾焚烧发电行业的上、中、下游,即从垃圾焚烧的原料性质、燃烧发电技术以及烟气控制方面对国内外生活垃圾焚烧技术进行了比较分析,认为随着生活垃圾量日益增长,生活垃圾焚烧技术仍是一种实现减量化、资源化必不可少的手段,但是需要提升焚烧技术,改进国产焚烧工艺,严格控制焚烧烟气中污染物的排放,建立实时监测点,避免造成二次污染。     

Site-specific health risk assessment of dioxins and furans in an industrial region with numerous emission sources

While the sources of releasing dioxins have received much attention, the health risks of incinerators are studied considerably more than those of other sources, such as metallurgical industry. Furthermore, risk assessments focus primarily on the effects of single sources; few have addressed the aggregate risks from multiple sources in a region. When many sources of dioxins exist in an area, such as the Industrial Park located in the densely populated district—Siaogang District in southern Taiwan where 17 primary known PCDD/F stationary emission sources are clustered, is the aggregate exposure to these sources imposing high risks even though individual sources comply with emission standards? The study combined the multimedia and multiple pathway exposure modeling and site-specific exposure scenario to assess dioxin risks contributed by the 17 emission sources in the District, including municipal waste incinerators, medical waste incinerators, sinter plants, electric arc furnace, secondary aluminum smelters, cement kilns, etc. The average cancer risk of a resident living in the District was found to be 3.43E−04 under the site-specific exposure scenario. The top emission source is the sinter plant, followed by the electric arc furnace. The information has driven the local government to conduct more complete assessment and at the same time to consider enforcing a stricter local standard of dioxin emissions in the Siaogang District.     

The partitioning of heavy metals in incineration of sludges and waste in a bubbling fluidized bed 2. Interpretation of results with a conceptual model

This work addresses the behavior, fate and/or partitioning of six targeted (Cd, Pb, Cr, Cu, Zn and Ni) heavy metals (HMs) in the incineration of sludges and waste in a bubbling fluidized bed (BFB) of 15 cm i.d. and 5.2m high followed by a filter chamber operated at 750-760 degrees C with a commercial ceramic filter. This paper presents three different things: (1) an in depth review of the published work relating to the problem of partitioning of the HMs in BFBs, (2) some more experimental incineration tests regarding the influence of the temperature of the bed of the BFB and the effect of the chlorine content in the feedstock on the partitioning of the HMs, and (3) the modelling of the partitioning of the HMs in the exit flows: bottom ash, coarse fly ashes, fine fly ash and vapour phase. The partitioning of the HMs is governed by fluid dynamic principles together with the kinetics of the diffusion of the HMs inside the ash particles and the kinetics of the reactions between the HMs and the components of the matrix of the ash. Some thermodynamic predictions do not fit the results from the BFB incinerator well enough because equilibria are not reached in at least three exit ash flows: coarse fly ash, fine fly ash and submicron particles. The residence time of these ash particles in these type of incinerators is very short and most of the HMs have no time to diffuse out of the ash particle. Finally, an examination was made on how in the ceramic hot filter the partition coefficients for the HMs increased, mainly for Cd and Pb, when the Cl-content in the feedstock was increased.