The use of municipal solid waste incineration ash in various building materials : a Belgian point of view

Huge amounts of waste are being generated, and even though the incineration process reduces the mass and volume of waste to a large extent, massive amounts of residues still remain. On average, out of 1.3 billion tons of municipal solid wastes generated per year, around 130 and 2.1 million tons are incinerated in the world and in Belgium, respectively. Around 400 kT of bottom ash residues are generated in Flanders, out of which only 102 kT are utilized here, and the rest is exported or landfilled due to non-conformity to environmental regulations. Landfilling makes the valuable resources in the residues unavailable and results in more primary raw materials being used, increasing mining and related hazards. Identifying and employing the right pre-treatment technique for the highest value application is the key to attaining a circular economy. We reviewed the present pre-treatment and utilization scenarios in Belgium, and the advancements in research around the world for realization of maximum utilization are reported in this paper. Uses of the material in the cement industry as a binder and cement raw meal replacement are identified as possible effective utilization options for large quantities of bottom ash. Pre-treatment techniques that could facilitate this use are also discussed. With all the research evidence available, there is now a need for combined efforts from incineration and the cement industry for technical and economic optimization of the process flow

Morteros de cemento mejorados con la adición de cenizas volantes carbonatadas provenientes de la incineración de residuos

This article presents the results of a research developing high performance cement mortars with the addition of municipal solid waste incineration fly ash (MSWIFA) stabilized as insoluble carbonates. The encapsulation of hazardous wastes in mortar matrixes has also been achieved. The ashes present high concentrations of chlorides, Zn and Pb. A stabilization process with NaHCO3 has been developed reducing 99% the content of chlorides. Developed mortars replace 10% per weight of the aggregates by treated MSWIFA. Physical/mechanical properties of these mortars have been studied. Presence of Zn, Pb, Cu and Cd has been also analyzed confirming that leaching of these heavy metal ions is mitigated. Conclusions prove better behavior of CAC and CSA mortars than those of CEM-I and CEM-II cement. Results are remarkable for the CAC mortars, improving reference strengths in more than 25%, which make them a fast-curing product suitable for the repair of structures or industrial pavements.Este artículo presenta los resultados del desarrollo de morteros mejorados con la incorporación de cenizas volantes de residuos sólidos urbanos inertizadas en forma de carbonatos. Además se consigue la encapsulación de un residuo peligroso. Las cenizas presentan una alta concentración de cloruros, Zn y Pb. Se ha desarrollado un proceso de estabilización con NaHCO3 reduciendo en un 99% el contenido de cloruros. Los morteros reemplazan un 10% en peso del árido por cenizas tratadas. Se han analizado sus propiedades físico/mecánicas y la presencia de Zn, Pb, Cu y Cd. Se demuestra un mejor comportamiento de los morteros de CAC y CSA que los de CEM-I y CEM-II y se mitiga el lixiviado de metales pesados. Los resultados son significativos en los morteros CAC al mejorar las resistencias de los de referencia en un 25%. Los morteros desarrollados son de curado rápido adecuados para la reparación de estructuras o soleras industriales

Beneficial Utilization of Municipal Solid Waste Incineration Ashes as Sustainable Road Construction Materials

Incineration of municipal solid waste (MSW) is common for energy recovery, and management of municipal solid waste incineration (MSWI) ashes has received a growing attention around the world. In the U.S., generation of MSW has increased up to 65% since 1980, to the current level of 251 million tons per year with 53.8% landfilled, 34.5% recycled and composted, and 11.7% incinerated with energy recovery. In the process of incineration, MSWI ash is being produced as byproducts; about 80 to 90% of the MSWI ash is bottom ash (BA) and 10 to 20% is fly ash (FA) by weight. The current practice of the U.S. is to combine both BA and FA to meet the criteria to qualify as non-hazardous, and all combined ashes are disposed in landfills. European countries have utilized MSWI BA as beneficial construction materials by separating it from FA. The FA is mostly limited to landfill disposal as hazardous material due to its high content of toxic elements and salts. BA has been actively recycled in the areas of roadbed, asphalt paving, and concrete products in many of European and Asian countries. In those countries, recycling programs (including required physical properties and environmental criteria) of ash residue management have been developed so as to encourage and enforce the reuse of MSWI ashes instead of landfill disposal. Moreover, many studies have demonstrated the beneficial use of MSWI ashes as engineering materials with minimum environmental impacts. On the other hand, the U.S. has shown a lack of consistent and effective management plans, as well as environmental regulations for the use of MSWI ashes., Due to persistent uncertainty of engineering properties and inconsistency in the Federal and State regulations in the U.S., however, the recycling of the MSWI ashes has been hindered and they are mostly disposed in landfills. In this research work, current management practice, existing regulations, and environmental consequences of MSWI ashes utilization are comprehensively reviewed worldwide and nationwide with an emphasis of the potential area of its utilization in asphalt paving and concrete product. This research also entails a detailed chemical and microstructural characterization of MSWI BA and FA produced from a Refuse Derived Fuel (RDF) facility in Florida so that the MSWI ash is well characterized for its beneficial uses as construction materials. The material characterization includes Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD) techniques. In addition, leaching experiments have been conducted to investigate the environmental properties (e.g. leachate concentration) of BA and ash-mixed hot mix asphalt (HMA) and Portland cement concrete (PCC). Leaching results reveals the reduced leaching potential of toxic material from MSWI ashes while incorporated in HMA and PCC. Lastly, a preliminary experimental approach has been devised for the vitrification of FA which is a promising thermal process of transferring material into glassy state with higher physical and chemical integrity to reduce toxicity so that utilization of FA can be possible

Recycling of Pre-Washed Municipal Solid Waste Incinerator Fly Ash in the Manufacturing of Low Temperature Setting Geopolymer Materials

In this work, three samples of municipal solid waste incinerators fly ash (MSWI-FA) have been stabilized in systems containing coal fly ash to create geopolymers through a polycondensation reaction. Monolithic products have been obtained with both MSWI fly ash as received and after the partial removal of chloride and sulfate by water washing. The polycondensation products have been characterized qualitatively by means of Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy and quantitatively, through the determination of the volume of reacted water and silicate. Furthermore, the heavy metals and chloride releases together with the physico-mechanical properties have been evaluated on the hardened products. In conclusion, considering the technological and environmental performances of the obtained geopolymers, they could be suitable for many non-structural applications, such as backfilling of abandoned quarries, decorative materials or brick fireplaces, hearths, patios, etc

Inertization, Utilization, and Safe Disposal of Incineration Residues

Combustion of coal or Municipal Solid Waste (MSW) caused air pollution and produces solid residues which contain high levels of toxic elements. The toxic characteristics of residues generated from combustion of MSW in waste-to-energy plants are strictly controlled by Federal and State Waste Management Regulations. According to Resource Conservation and Recovery Act (RCRA), residue generated from combustion of MSW is considered hazardous and must be tested according to EPA Toxic Characteristics Leaching Procedure (TCLP) Method 1311 and suitably treated for its safe disposal to landfills. Experiments with various treatment chemicals as primary independent variable had earlier been conducted by several agencies and facilities. The author has successfully developed two new cost-effective solutions for stabilizing heavy metals in MSW residues to cover the gap between the leachability concentrations of toxic elements observed in residues and the leachability toxicity limits as per EPA\u27s regulatory threshold. These methods include treating MSW residue fly ash (FA) with 2% dolomitic lime by weight, or by injecting aqueous (39% concentration) sodium sulfide at a controlled rate. The extensive full scale experimental study was carried out at 240 t/day capacity Hampton/NASA waste-to-energy mass burn MSW Incinerator (MSWI). This process has showed savings to the extent of $150,000 per year by treating the plant\u27s combustion residues with aqueous sodium sulfide over the use of dolomitic lime for ash treatment. Results of the prior studies for treatment of toxic wastes have been synthesized and randomized experimental plan has been planned for conducting this research. Thus valid and defensible results have been obtained that show repeatability of the identified treatment method in varying operating conditions of the combustion process. The research plans and experimental design methods are detailed in section 1.16 of Chapter 1. The treatment method invented has also shown better control of the leachability of toxic heavy metals than previously used chemical treatment methods. Comparative study showing the level of leachability of toxic heavy metals with different treatment methods are detailed in Chapter 5. The best management practices for use and disposal of such wastes have been discussed

THE POSSIBILITY OF COPROCESSING MUNICIPAL SOLID WASTE - MSW IN CLINKER KILNS TO CEMENT PRODUCTION

The objective of this paper is to present an analysis of coprocessing in a cement production plant using Municipal Solid Waste - MSW as a secondary fuel and show the main advantages that burn into a incineration plant. The manufacture of Portland cement is a process that requires a large consumption of thermal and electrical energy and front of the immense worldwide energetic demand has increased its value every day. The typical operating cost involving this energy achieves 40% of the final product and due to increasing world consumption justifies the efforts to reduce the costs associated with its production. The use of high efficiency equipment coupled with the replacement of fossil fuels and conventional raw material for alternative products has given good results. The method of disposal of MSW in landfills in large urban centers is being used less and less. The creation of environmental laws increasingly severe shortages of allied areas not disturbed and the high cost of construction and operation of landfills hinders its viability. Moreover, there is a problem related to the emissions  of gaseous and liquid effluents that help raise the cost for its control and treatment. The MSW, when recovered and separated, can become recyclable products and as energy sources. After separation of the usable material (organic matter and recyclable), remaining MSW materials with sufficient calorific value can be used in kilns to produce clinker. Moreover, the ash resulting from combustion may be incorporated in the clinker decreasing the initial amount of raw material. The use of MSW as alternative fuel has shown to be feasible in the clinker kiln, but their use is still limited by their availability, since their segregation is rarely practiced. The substitution of alternative inputs introduce restrictions to the process which must be safely handled in order to ensure the minimum quality and productivity of cement production plants. The use of MSW must have a thorough characterization of your composition, because of directly influences in the final product

Urban mining of municipal solid waste incineration (MSWI) residues with emphasis on bioleaching technologies: a critical review

Metals are essential in our daily lives and have a finite supply, being simultaneously contaminants of concern. The current carbon emissions and environmental impact of mining are untenable. We need to reclaim metals sustainably from secondary resources, like waste. Biotechnology can be applied in metal recovery from waste streams like fly ashes and bottom ashes of municipal solid waste incineration (MSWI). They represent substantial substance flows, with roughly 46 million tons of MSWI ashes produced annually globally, equivalent in elemental richness to low-grade ores for metal recovery. Next-generation methods for resource recovery, as in particular bioleaching, give the opportunity to recover critical materials and metals, appropriately purified for noble applications, in waste treatment chains inspired by circular economy thinking. In this critical review, we can identify three main lines of discussion: (1) MSWI material characterization and related environmental issues; (2) currently available processes for recycling and metal recovery; and (3) microbially assisted processes for potential recycling and metal recovery. Research trends are chiefly oriented to the potential exploitation of bioprocesses in the industry. Biotechnology for resource recovery shows increasing effectiveness especially downstream the production chains, i.e., in the waste management sector. Therefore, this critical discussion will help assessing the industrial potential of biotechnology for urban mining of municipal, post-combustion waste

A proposed walkway system constructed from selected combustion residues

This thesis studies a new more affordable way to build sidewalks in the U.S. Typical sidewalks are often impractical on many roads because of a steep runoff slope and/or close proximity to the drainage ditch. Also, if future road widening is required, the sidewalk must be removed. This thesis proposes a structure called a Lanwalk which is an elevated sidewalk made of precast units. A Lanwalk could simultaneously serve as a sidewalk and potentially as a guardrail. It can be placed over drainage areas if necessary without obstructing the flow of water. Lanwalks can be easily installed and relocated if necessary. This thesis examines the possibility of using high amounts of waste ash as an admixture during the construction of Lanwalks or sidewalks to lower cost and save landfill space. The two waste products examined are municipal solid waste incinerator bottom ash (IBA) and coal fly ash (CFA)

Environmental Ranking Considerations For Setting Up A Recuperative Energy Incinerator.

The study looks into environmental ranking considerations in setting up a recuperative energy incinerator in Malaysia. Major impacts on the environmental aspects covering land, water and air were put into considerations