Municipal Solid Waste Ash Research Articles

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water.

In this study, municipal solid waste bottom ash (MSW-BA) and fly ash (MSW-FA) were used as a source of aluminosilicate to prepare geopolymer (GEO) adsorbents (GEO-MSWBA and GEO-MSWFA) for the removal of methylene blue (MB) from water. The effects of temperature, pH, and initial concentration on the MB adsorption onto GEO-MSWBA and GEO-MSWFA were evaluated. The adsorption isotherms parameters and thermodynamics were also determined. Detailed physical and chemical characterizations of the prepared adsorbents were carried out to further understand their impact on MB adsorption. The results from the scanning electron microscopy revealed a uniform granule-sphere like structure on both prepared geopolymers, which would facilitate the MB adsorption onto the adsorbents. The X-ray diffraction allowed observation of the microstructural transformations that occur after the alkaline activation. The surface areas of the GEO-MSWBA and the GEO-MSWFA were recorded as 32.78 m2/g and 4.5 m2/g, respectively. From the Fourier transform infrared, a stretching vibration of the aluminosilicate tetrahedral was observed, which indicated the success of geopolymerization. The prepared geopolymers showed a high capability of MB adsorption from an aqueous solution. The adsorption process was best suited and explained using the Langmuir isotherm model with a maximum adsorption capacity of 666.7 mg/g for the GEO-MSWBA (at 25°C) and 769.2 mg/g for the GEO-MSWFA (at 35°C). The positive value of the enthalpy (ΔHo) for the GEO-MSWBA suggested the reaction favored endothermic reaction while the negative value of entropy (ΔSo) indicated a solid/liquid random interaction. On the other hand, the negative ΔHo value for the GEO-MSWFA indicated the reaction followed an exothermic reaction causing energy to be released, the positive ΔSo value indicated a good affinity at the solid-liquid surface. The overall negative value for Gibbs free energy (ΔGo) for both adsorbents suggested the adsorption was spontaneous and feasible. It was also inferred that n- π interaction, direct and indirect hydrogen bond, and electrostatic interaction between the MB and the prepared geopolymers facilitated the adsorption process. The current study shows that the GEO-MSWBA and the GEO-MSWFA have a great potential of removing MB as a cationic dye from water without performing any sort of laborious pretreatments.

Comparison of bio-clogging characteristics of geotextiles in MSW and bottom ash co-disposal landfills

Bio-clogging of geotextile is a big challenge for the leachate collection system in landfills. It is important to understand the characteristics of geotextile bio-clogging to develop control technologies. This study investigated the characteristics of geotextile bio-clogging in municipal solid waste landfill (MSW_G) and bottom ash (BA) co-disposal landfill (BA_G). Results showed that the bio-clogging mass of per area in MSW_G and BA_G was 49 ± 5 g/m2 and 57 ± 3 g/m2, respectively. Bio-clogging was dominated by live cells in both MSW_G and BA_G. The confocal laser scanning microscopy images revealed that live cells percentage was 46% in MSW_G, while it increased to 77% in BA_G. In contrast, the percentage of the dead cells was 47% and 9% in MSW_G and BA_G, respectively. The biofilm formed in BA _G was thinner and denser than that in MSW_G. Based on the microbial analysis, the biofilms of BA_G had a higher genetic amount and diversity than these of MSW_G. The total amount of extracellular polymeric substances in BA_G was 45.29 ± 4.52 mg/g volatile suspended solids, which was 1.5 times of that in MSW_G. The co-disposal of BA increased the microbial diversity and accelerated bio-clogging due to the high calcium concentration. These findings provide a better understanding of the bio-clogging characteristics, which is helpful to control bio-clogging in co-disposal landfills.

Characterization of Florida, U.S. landfills with elevated temperatures

The occurrence of elevated temperatures within landfills is a challenging issue for landfill operators to detect and correct. Little is known regarding the causes of elevated temperatures (ETs) or the number of landfills currently operating under such conditions. Therefore, the goal of this research was to determine which landfills within Florida have been impacted by ETs, and to develop a more complete understanding of the factors that may lead to these landfills becoming elevated temperature landfills (ETLFs). Historical landfill gas wellhead data, waste deposition reports, and landfill site geometry were collected for 27 landfill cells through the Florida Department of Environmental Protection electronic document management system, OCULUS database and from landfill operators and owners. These data were evaluated to quantify the characteristics that result in landfills having ‘elevated’ temperatures. Gas data included landfill gas temperatures and methane, carbon dioxide, and balance gas content. Furthermore, landfill maps were created in ArcGIS to observe spatial distribution of ETs in landfills over time. Upon analysis of the landfill gas wellhead data, it was discovered that 74% of studied landfill cells had ET readings; regulatory limits specify a maximum allowable gas temperature of 55 °C (131 °F). It was discovered that 37% of landfill cells contained MSW ash; of these cells, 90% of them are considered ETLFs. ETLF cells are on-average double the site area and approximately 6 m deeper than the average non-ETLF cell. Furthermore, results suggest that heat propagation in most landfills is limited; however, heat propagation is possible if gas wells are turned off for an extended time period.

Influence of Sodium Oxide on the Fusion of Solid Municipal Waste Ash

The model composition of municipal solid waste (MSW) and its ash chemical composition are characterized. Mineral compounds and melting points are studied using a variety of analytical methods, including XRD, FTIR, and AFT. The main parameters of slag formation are calculated: base-to-acid ratio, slag viscosity index, and fouling coefficient. Solid municipal waste ash contains significant amounts of CaO, SiO2 and Al2O3. Using the Terra program, thermodynamic calculations of the chemical equilibria of the CaO–SiO2–Al2O3–Na2O systems containing from 5 to 25% sodium oxide are performed. It is experimentally shown that each 5 wt % increase in the Na2O content reduces the characteristic melting temperatures of MSW ash by 30–50°С.

Numerical modeling of clogging of landfill leachate collection systems with co-disposal of municipal solid waste (MSW) and incinerator ash

The influence of co-disposal of municipal solid waste (MSW) and incinerator ash used as daily cover on the clogging of leachate collection systems (LCSs) from landfills is examined. The “BioClog” model is used to simulate the fate and transport of the nine leachate constituents most responsible for clogging the LCSs as they move through the porous media. It then calculates the thicknesses of five films that attach to the porous media and the effect of this clog mass–volume on the porosity and hydraulic conductivity of the granular material. Then it models the consequent growth in the leachate mound with increasing clog mass over time until the service life of the LCS is reached. The modeling shows that the concentrated source of leachable minerals in the incinerator ash accelerates the clogging rate and reduces the service life of the LCSs compared to inert daily cover. If an LCS is not designed to accommodate these higher concentrations of cations in the influent leachate during the landfill operating period, the ash can significantly reduce the LCS service life. Means of extending LCS service life are discussed. A practical technique is also utilized to estimate the service life of LCSs with conservative and reasonable agreement with BioClog.

Waste type, incineration, and aeration are associated with per- and polyfluoroalkyl levels in landfill leachates

Per- and polyfluoroalkyl substances (PFAS) are found in many consumer products which will be ultimately disposed in landfills. Limiting environmental contamination and future exposures will require managing leachates from different types of landfills, each with different PFAS levels depending upon the source of the waste. The objective of this study was to evaluate the influence of waste type and on-site treatment on PFAS levels in landfill leachates. Eleven PFAS species (7 carboxylic acids, 3 sulfonic acids, and 5:3 fluorotelomer carboxylic acid) were evaluated in leachates from municipal solid waste (MSW), construction and demolition (C&D), MSW ash (MSWA), and a mixture of MSWA and MSW with landfill gas condensate (MSWA/MSW-GC). Leachates were also analyzed before and after on-site treatment at two of these facilities. Results indicate that MSWA leachate had significantly lower PFAS levels relative to other leachate types. Lower total PFAS concentrations in MSWA leachates were correlated with an increase in incineration temperature (R2 = 0.92, p = 0.008). The levels of PFAS in untreated C&D and untreated MSW leachate were similar. The levels of targeted PFAS species in MSW leachate for one of the facilities evaluated increased after on-site landfill treatment presumably due to the conversion of PFAS precursors in the untreated leachate sample.

Strength and leachability of geopolymers with the addition of municipal solid waste ashes

The paper presents the results of the study concerning the possibility of immobilization of secondary waste from municipal waste incineration plants in geopolymers. The study was conducted for 2 different sources of ash from Poland and Lithuania. Three different types of waste were tested. Geopolymers were made with 70% added waste from incineration plants. The samples were made in many variants: geopolymers were made on the basis of fly ash and metakoline and waste was added untreated and after washing with water in a ratio of 1:5 (solid/liquid). Compressive strength and water leaching tests were carried out. As a result of the study, geopolymers as a material for immobilization of secondary waste from waste incineration plants were found to be useful. Water leaching tests proved that all the tested wastes stabilized in geopolymers are characterized by very low leachability values of metals suchas: copper, zinc, lead, etc.

Metals Leaching in Permeable Asphalt Pavement with Municipal Solid Waste Ash Aggregate

The leaching behaviors of four heavy metals (Zn, Pb, Cu and Cr) from unbounded municipal solid waste incineration-bottom ash aggregate (MSWI-BAA) and permeable asphalt (PA) mixture containing MSWI-BAA were investigated in the laboratory. The horizontal vibration extraction procedure (HVEP) test and a simulated leaching experiment were conducted on MSWI-BAA with three particle sizes, but only the simulated leaching experiment was carried out on a type of PA specimen (PAC-13) with and without these MSWI-BAAs. Leaching data were analyzed to investigate the leaching characteristics, identify the factors affecting leaching and assess the impact on the surrounding environment. Results indicated that the leaching process was comprehensively influenced by contact time, leaching metal species and MSWI-BAA particle size, regardless of MSWI-BAA alone or used in PAC-13 mixture. The leaching concentrations of Cr, Zn and Pb from MSWI-BAA in HVEP testing was strongly related to MSWI-BAA particle size. The use of MSWI-BAA in PAC-13 mixture did not change the basic tendency of heavy metal leaching, but it led to an increase of Cr and Zn in leachate overall. The leachate from the MSWI-BAA and PAC-13 mixture with MSWI-BAA was shown to be safe for irrigation and would have very little negative impact on surrounding surface and underground water quality.

Potential Use of Municipal Solid Waste Ash (MSWA) As Sustainable Construction Bricks

Uncontrolled infrastructure development may produce excessive carbon emission and scarcity of natural resources, that exploited for the mean of development. The reuse of waste materials will promote material ecology and the cradle to cradle concept. This study utilizes Municipal Solid Waste Ash (MSWA) as a potential target material in replacing laterite soil that is nonrenewable natural resources. Mix design, compositions were established for industrial trial of brick making. Laterite soil on its own (100%) and in combination with MSWA, (50:50) stabilized with PC and Lime at 20% and 30% were used to produce bricks. The bricks were then air dried. Two engineering properties, compressive strength and water absorption were studied. The investigation results show that compressive strength and water absorption of laterite soil combine with MSWA at (50:50) recorded higher strength compared to when laterite soil were used alone. This suggests viability and feasibility of using waste material in brick making.

Prediction of physical separation of metals from soils contaminated with municipal solid waste ashes and metallurgical residues

Environmental legislation is forcing industrialized countries to rehabilitate contaminated lands. Expensive solutions are available to treat soils contaminated by metals (e.g., solidification, stabilization, and landfilling). Physical remediation techniques, which are less expensive, are able to efficiently separate metals from contaminated soils under specific physical conditions. In the current study, densimetric and mineralogical characterization of fractions of soil between 0.25 and 4 mm contaminated by municipal solid waste (MSW) ashes and metallurgical waste was performed. This characterization confirmed the usefulness of the jig and wet shaking table for separating the metal contaminants from the soil. Mineralogical characterization allowed the prediction of treatment efficiencies and potential limits. The jig performance was optimized based on densimetric characterization. Water washing coupled with ferrous material extraction using magnetic separation, and, attrition scrubbing coupled with the jig and wet shaking table, led to a removal yield varying from 42.1% to 83.4% for Ba, Cu, Pb, Sn, and Zn from the fraction of soil >0.25 mm contaminated by MSW ashes. The recovered treated mass varied from 57.1% to 73.4% (by weight). For the fraction of soil >0.25 mm contaminated with metallurgical residues, Cu and Zn removal yields were higher than 57.5%. The recovered treated mass from this soil fraction corresponded to 64.8% (by weight). Depending on the level and leachability of contaminants, the soil fractions <0.25 mm were recommended for appropriate treatments (solidification or stabilization) or for safe disposal via landfills.

English

Lead (Pb) is an inorganic conservative pollutant poses a risk to soils and water resources. Quantifying the potential hazard impacts of Pb in soils needs further circumstances about its mobility and retention as well. The objective of this study was to evaluate the effects of municipal solid waste ash (MSWA) on mobility and distribution of Pb in two types of soil textures. The extent of Pb mobilization in soils amended with different application rates of MSWA has been quantified by soil columns experiment under steady state conditions. Transport of Pb was studied in soil columns by applying Pb solution of 150 mg/L at the rate of 0.09 cm/min for loamy sand soil and 0.035 cm/min for sandy loam soil. The mathematical model- HYDRUS-2D was used to describe this transport. The results indicated that Pb concentrations were extremely low in the leaching solutions collected from soil columns over time regardless of the application rates of MSWA. Application of MSWA increased the recovery of Pb in both soils achieving superiority in loamy sand soil. The Pb distributed in the soil columns ranged between soil leaching solutions and sorbed phase, of which the greater portion was in the sorbed phase. Lead move slowly through soils columns and the distance of movement was about 5 cm to the soil surface and then the concentrations decreased down the soil columns and later disappeared beyond a depth of to 7 cm. Mass balance calculations of Pb according to the HYDRUS-2D mathematical model resulted in values that were similar to those of the experimental data (error ≤ 5%). A soil quality indicator is considered as a key element of sustainable agriculture and hence soil quality plays an important role in deciding the MSWA methods.

Utilization of Municipal Solid Waste Ash in Concrete by partial Replacement of Cement

The problem of solid waste is being emerged increasingly due to the increased quantity of solid waste as a result of population’s increase .From the point of view of environmental and energy concerns, it is preferable to reuse the organic and inorganic components of solid waste in order to minimize the cost. In this investigation, the possibility of using solid waste ash (SWA) as a partial replacement of cement and its effect on the mechanical properties of concrete was studied. Samples of municipal solid wastes were collected were burring and changed to ash. A total of 50 cubes, 15 small cubes, and 30 cylinders, as well as 5 prisms were prepared .Various properties of solid waste ash are added to the cement mistures with percent's of 5, 10, 15 and 20 percent by weight of solid waste ash. A concrete mix with a percent solid waste ash was used as reference. Pozzolanic activities of all mortars, and setting times of all pastes, and workability of all mixes were investigated .Compressive strength, splitting tensile strength, absorption, and drying shrinkage for reference for reference and solid waste concrete specimens were investigated at various ages. Results demonstrate that the pozzolanic activity was within ASTM requirements for the cases of 5% and 10% ash replacement. For 15 and 20 percent replacement this activity was only slightly less than the ASTM value. The 90-day compressive strength rose, in comparison with control specimens, with 5 percent replacement and was only slightly lower at 10 percent replacement. In splitting tensile strength was at least equal to reference specimens for all replacement ratios. The rise in these values, over the reference specimens, ranged between 0 to 21 percent for the case of 20 and 5 percent replacement, respectively.

Lead Transport in Soils Amended with Municipal Solid Waste Ash

Lead Transport in Soils Amended with Municipal Solid Waste Ash

Capture of CO2 in Fluidized bed and Fixed bed using MSW ash and CaO

Capture of CO2 in Fluidized bed and Fixed bed using MSW ash and CaO

Waste heat generation: A comprehensive review

A comprehensive review of heat generation in various types of wastes and of the thermal regime of waste containment facilities is provided in this paper. Municipal solid waste (MSW), MSW incineration ash, and mining wastes were included in the analysis. Spatial and temporal variations of waste temperatures, thermal gradients, thermal properties of wastes, average temperature differentials, and heat generation values are provided. Heat generation was influenced by climatic conditions, mean annual earth temperatures, waste temperatures at the time of placement, cover conditions, and inherent heat generation potential of the specific wastes. Time to onset of heat generation varied between months and years, whereas timelines for overall duration of heat generation varied between years and decades. For MSW, measured waste temperatures were as high as 60–90°C and as low as −6°C. MSW incinerator ash temperatures varied between 5 and 87°C. Mining waste temperatures were in the range of −25 to 65°C. In the wastes analyzed, upward heat flow toward the surface was more prominent than downward heat flow toward the subsurface. Thermal gradients generally were higher for MSW and incinerator ash and lower for mining waste. Based on thermal properties, MSW had insulative qualities (low thermal conductivity), while mining wastes typically were relatively conductive (high thermal conductivity) with ash having intermediate qualities. Heat generation values ranged from −8.6 to 83.1MJ/m3 and from 0.6 to 72.6MJ/m3 for MSW and mining waste, respectively and was 72.6MJ/m3 for ash waste. Conductive thermal losses were determined to range from 13 to 1111MJ/m3yr. The data and analysis provided in this review paper can be used in the investigation of heat generation and thermal regime of a wide range of wastes and waste containment facilities located in different climatic regions.

Study of Asphalt Binder Oil Residue and Municipal Solid Waste Ash to be Used in Low Traffic Pavements

The great generation of urban solid has been a concern in several countries. This work presents a study with two materials: the asphalt binder oil residue accumulated in the bottom of asphalt tanks and the municipal solid waste ash, to be used, respectively, as a substitute of conventional binder in asphalt mixtures and for soil stabilization in pavements base layers. Were evaluated properties as the mechanical behavior of the mixtures through experimental tests. The results show the potential of incorporating these residues for low traffic roads, allowing the construction of low cost roads and an environmental use of the residue.

A case-study of landfill minimization and material recovery via waste co-gasification in a new waste management scheme

This study evaluates municipal solid waste co-gasification technology and a new solid waste management scheme, which can minimize final landfill amounts and maximize material recycled from waste. This new scheme is considered for a region where bottom ash and incombustibles are landfilled or not allowed to be recycled due to their toxic heavy metal concentration. Waste is processed with incombustible residues and an incineration bottom ash discharged from existent conventional incinerators, using a gasification and melting technology (the Direct Melting System). The inert materials, contained in municipal solid waste, incombustibles and bottom ash, are recycled as slag and metal in this process as well as energy recovery.Based on this new waste management scheme with a co-gasification system, a case study of municipal solid waste co-gasification was evaluated and compared with other technical solutions, such as conventional incineration, incineration with an ash melting facility under certain boundary conditions. From a technical point of view, co-gasification produced high quality slag with few harmful heavy metals, which was recycled completely without requiring any further post-treatment such as aging. As a consequence, the co-gasification system had an economical advantage over other systems because of its material recovery and minimization of the final landfill amount.Sensitivity analyses of landfill cost, power price and inert materials in waste were also conducted. The higher the landfill costs, the greater the advantage of the co-gasification system has. The co-gasification was beneficial for landfill cost in the range of 80 Euro per ton or more. Higher power prices led to lower operation cost in each case. The inert contents in processed waste had a significant influence on the operating cost.These results indicate that co-gasification of bottom ash and incombustibles with municipal solid waste contributes to minimizing the final landfill amount and has great possibilities maximizing material recovery and energy recovery from waste.

Characteristics of element distributions in an MSW ash melting treatment system

Thermal treatment of municipal solid waste (MSW) has become a common practice in waste volume reduction and resource recovery. For the utilization of molten slag for construction materials and metal recovery, it is important to understand the behavior of heavy metals in the melting process. In this study, the correlation between the contents of elements in feed materials and MSW molten slag and their distributions in the ash melting process, including metal residues, are investigated. The hazardous metal contents in the molten slag were significantly related to the contents of metals in the feed materials. Therefore, the separation of products containing these metals in waste materials could be an effective means of producing environmentally safe molten slag with a low hazardous metals content. The distribution ratios of elements in the ash melting process were also determined. The elements Zn and Pb were found to have a distribution ratio of over 60% in fly ash from the melting furnace and the contents of these metals were also high; therefore, Zn and Pb could be potential target metals for recycling from fly ash from the melting furnace. Meanwhile, Cu, Ni, Mo, Sn, and Sb were found to have distribution ratios of over 60% in the metal residue. Therefore, metal residue could be a good resource for these metals, as the contents of Cu, Ni, Mo, Sn, and Sb in metal residue are higher than those in other output materials.

Polychlorinated Dibenzo-p-dioxin and Dibenzofuran (PCDD/F) Emission Behavior during Incineration of Laboratory Waste. Part 1: Emission Profiles Obtained Using Chemical Assay and Bioassay

This study describes polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) behavior during the incineration of laboratory waste, including combustible laboratory solid waste (LSW), laboratory plastic waste (LPW), and organic laboratory liquid waste (LLW). Stack flue gas (SFG), input materials, bottom ash (BTA), first quenching tower ash (FQA), secondary quenching tower ash (SQA), and baghouse ash (BHA) were sampled and analyzed using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) assay and bioassay. The PCDD/F concentration of SFG met the standard in Taiwan. The Cl levels of LPW and LLW were roughly equivalent to that of municipal solid waste (MSW). Therefore, the SFG concentration, content of fly ash, and distribution behavior of PCDD/Fs are reasonably similar to those of MSW incinerators. The LSW had an extremely high Cl level (11.4%). The emission factor of the whole incineration system was 888 µg I-TEQ/ton-waste, which is 10-fold higher than that of MSW. The PCDD/F was mainly in BTA (31.6 wt.%) and fly ash (63.1 wt.%), resulting in higher PCDD/F level of ashes compared with that of MSW ashes. Both HRGC/HRMS analysis and bioassay results show similar PCDD/F emission characteristics during the incineration of LW. In addition, the linear regression between the values acquired using these two methods show a good relation (R 2 > 0.84), indicating that Ad-DR bioassay is a promising fast-screen method for determining PCDD/F levels.

Effect of municipal solid waste ash on comprehensive strength characteristics of an interlocking block masonry wall

Masonry is a layered composite which consists of mortar and masonry units. A good bond between the units is essential and determines how the masonry transfers and resist stresses due to applied loads. In this study interlocking blocks were used in masonry wall construction in order to introduce uniformity in the wall model by eliminating mortar as a binding media. The blocks were moulded in a CINVA-Ram machine by replacing 0%, 2%, 5% and 10% of municipal solid waste ash (MSW ash) as a stabilizing agent. The compressive strengths of individual blocks were obtained after curing for 7, 14 and 28 days. The 2%MSW ash replacement gave the highest compressive strength and was used in constructing the wall model. The wall models were loaded in compression in direction normal to bed joints. The 2%MSW ash stabilized Juja soil wall failure was generally associated with diagonal cracks and bulging of the wall from sides. A maximum crack width of 40 mm wide occurred at failure with the central deflection of the wall reaching 20 mm at an ultimate failure stress of 2.49 N/mm 2 . The failure mode of un-stabilized Juja soil wall model was mainly due to vertical cracks forming below the load application point. The ultimate failure stress of un-stabilized Juja soil wall was 2.5 N/mm 2 , however its central deflection was low than that of stabilized wall. Conversely, un-stabilized Murang’a soil wall failed by crushing introduced by vertical cracks. A maximum stress of 0.997 N/mm 2 was achieved with a central deflection of 12 mm. Stabilized Murang’a soil had a low failure stress of 0.85 N/mm 2 as compared to the un-stabilized soil. The wall failed due to a combination of horizontal and diagonal cracks forming on the wall. In both cases the strength of individual blocks was higher than that achieved in the wall models. The progression of failure stress cracks for 2%MSW ash stabilized wall model was corresponding to that recommended in the code of practice for masonry, thus the same code can be used in design of stabilized masonry walls. Keywords: Compressive strength, failure mode, interlocking blocks, stabilization, Solid Waste Ash. Nigerian Journal of Technological Research , 8(2), 2013