Incinerator Ash Research Articles

Comparison of the PFAS and physical-chemical parameter fluctuations between an ash landfill and a MSW landfill

Studies of per- and polyfluoroalkyl substances (PFAS) fluctuations at landfills have focused on municipal solid waste (MSW) leachate. Few studies exist that evaluate fluctuations (defined by the coefficient of variation, CV) in MSW incinerator ash (MSWA) landfill leachate and that evaluate PFAS fluctuations in stormwater, groundwater, and treated liquids on-site. In this study, aqueous landfill samples (leachate, treated leachate, stormwater, gas condensate, ambient groundwater, and effluent from a groundwater remediation system) were collected from a MSW and an MSWA landfill geographically located within close proximity (less than 40 km). The objective of this study was to compare the leachate compositions between these two landfill types and to evaluate temporal variations. Results indicated that the CV of total detected PFAS concentrations in leachate was higher for the MSW landfill (CV = 43 %) compared to the MSWA landfill (CV = 16 %). The total detected PFAS concentration in MSW leachate samples (mean: 9641 ng/L) was higher than in MSWA leachate samples (mean: 2621 ng/L) (p < 0.05). Within a landfill, PFAS concentrations were correlated (rs > 0.6, p < 0.05) with alkalinity, total organic carbon (TOC), and ammonia. Results from the on-site leachate treatment system at the MSW landfill indicated reductions in COD, TOC, and ammonia; however, the ∑26PFAS concentration increased 3 % after the treatment. Overall, results demonstrated that differences between landfill types and fluctuations in PFAS within landfills should be considered when designing landfill leachate collection and treatment systems to remove PFAS. The comparative analysis in this study can provide insights into optimizing leachate management for MSW and MSWA landfills.

INFLUENCE OF PARTICLE SIZE DISTRIBUTION OF HAZARDOUS SOLID WASTE INCINERATION ASHES (HSWIA) ON LANDFILL LEACHATE FILTRATION

The study examines the reuse of hazardous waste incineration ashes in landfill leachate treatment. Its objective is to assess how the particle size distribution of the ashes affects the reduction of physicochemical parameters in leachate at the Caucaia Sanitary Landfill in Ceará, Brazil, thus valorizing them and minimizing their disposal in landfills. Two filtration columns with ashes of different particle sizes (F1 sieved and F2 raw) were set up. Leachate collected from the landfill was analyzed before and after filtration, demonstrating effectiveness in removing parameters such as phosphorus, nitrite, turbidity, nitrate, etc. The characterization of the ashes revealed differences between the samples, including varying levels of oxides and particle sizes. Results suggest potential use in pre-treatment to reduce pollutant loads before the primary treatment of leachate. The study underscores the potential of incineration ashes to enhance leachate treatment and reduce the environmental impact of improper disposal.

An LC3-type binder produced with marine clay and municipal waste incineration fly ash

Marine clay and municipal waste incineration ash are two major wastes in Singapore. The low reactivity of marine clay and high chloride (Cl) content in incineration fly ash (IFA) limit their application as supplementary cementitious materials. In this study, these wastes are synergistically used to prepare an LC3-type binder. The compressive strength of the proposed binder is comparable to or higher than the OPC references at 7 and 28 days. Pore-filling AFm crystals are ubiquitous in the hardened paste, which are characterized as hemicarbo-AFm and (Cl-, CO32-)-AFm when IFA was and was not subjected to Cl-removal treatment, respectively. A significant conversion of AFt to AFm is observed during the first 28 days. The leaching of Cl and certain heavy metals are reduced compared with the case of IFA-OPC binary binder. This work broadens the concept of LC3 binder system, and may inspire circulation of wastes in Singapore for construction practice.

Quality of paving blocks soaking water made from medical waste incineration ash

Given the ash level of medical waste incineration utilized as a raw material mixture that contains metal compounds, dumping the paving block immersion water into rivers could result in a drop in water quality. The purpose of this study is to evaluate water quality during immersion of paving blocks made from medical waste incineration ash. Water quality was measured by five measurements in water before immersion, soaking for 7 days, 14 days, 21 days, and 28 days. The test method used is in accordance with SNI 6989-84:2019. The metal compounds examined in this study were Pb (lead), Copper (Cu), Nickel (Ni), and cadmium (Cd). Laboratory tests were conducted at the Jasa Tirta I Environmental Laboratory and the Sukoharjo Environmental Service. It can be concluded that there is no pollution due to heavy metals contained in paving blocks. The results show that the soaking water for 7 to 28 days is still below the specified quality, so paving block-making activities using a mixture of medical waste incineration ashes can be carried out. The need for other studies measuring the levels of other metals such as Cr, Hg, Sn, Ti, and Zn.

Effect of Temperature and Ratio for the Immobilization of Zinc Oxide in Aluminium Rich Ceramics

Zinc is one of the dangerous elements that is frequently present in municipal solid waste incinerator ash. When exceeding specific limits, there are various diseases and disorders caused by accumulation of zinc in nature as their characteristics is not biodegradable. By using zinc oxide to imitate zinc sludge, this study reveals the immobilization mechanisms that occur when zinc and ceramic precursors are used as waste-to-resources strategies. From the result, immobilization occur better at higher temperature at 10000C where the formation of Al2O4Zn is higher. Meanwhile, ratio 1:1 of ZnO and Al2O3 shows a better result of formation Al2O4Zn. Hence, it is possible to use the sintering process with precursors to turn hazardous wastes into secure products where the heavy metals can form phases that can demonstrate adequate stability due to irreversible phase transformation.

Use of treated municipal waste incinerator ashes as concrete aggregate after fragmentation and sorting

AbstractAnnually about 5.7 million tons of waste incinerator ash accumulate in Germany through the incineration of municipal waste. The new method of electrodynamic fragmentation allows waste incinerator ashes with complex material compositions to be broken at material interfaces and then sorted into materially pure components. The aim of current ASHCON research project is to substitute natural aggregate of the grain fraction 2/8 mm in conventional formulations for ready‐mixed concrete and concrete blocks by these secondary raw materials in order to keep them within the material cycle and reduce the use of primary raw materials. Since the utilization of fragmented waste incinerator ashes in concrete must be below the limit values with regard to possible pollutant concentrations (e.g. heavy metal concentrations), the suitability of a so‐called non‐destructive neutronic analysis method on real samples is also being investigated within the ASHCON project. The first results of sample collection, preparation and analysis as well as material properties of the produced concretes with the implementation of mineral residues from waste incinerator ashes are presented in this paper.

Use of residues as fillers in alkali‐activated binders

AbstractThe demand for resource saving and recycling of waste materials to achieve a circular economy is increasing. In Europe, nearly all blast furnace slag and fly ash are used as supplementary cementitious material. Furthermore, there is urgent need to reduce the CO2 emissions of building materials industry. Like in OPC‐based concretes, the reduction in the binder content by the use of fillers can be a way to reduce the CO2 emissions of alkali‐activated binders even further. Therefore, this study aims at the use of industrial residues as a filler in alkali‐activated materials to reduce the CO2 emissions of alkali‐activated binders. In this study, three industrial residues including municipal solid waste incineration ash (MSWIA), steel slag (SS) and ash formed by the thermal treatment of tar‐containing asphalt (EcoF) are used as fillers for alkali‐activated binders and are compared with fine quartz powder as an inert reference filler. The binder is ground granulated synthetic slag, which is replaced with the four filler materials at a 32 vol.% replacement level. The samples are reacted with 15 and 25 wt.% NaOH solution. The results show a potential advantage of using SS and EcoF as a filler in concrete as they exhibited a slightly higher compressive strength at all tested ages compared to quartz powder.

Rare Earth Elements Recovery and Waste Management of Municipal Solid Waste Incineration Ash.

The advancements in high-tech products and pursuit of renewable energy demand a massive and continuously growing supply of rare earth elements (REE). However, REE production from mining is heavily restricted by technoeconomic limitations and global geopolitical tensions. Municipal solid waste incineration ash (MSWIA) has been recently recognized as a potential alternative for REE recovery. This study applies and optimizes a green modular treatment system using organic ligands for effective REE recovery and concentration from MSWIA with minimal generation of secondary wastes. Citrate extracted >80% of total REE at pH 2.0 and ∼60% at pH 4.0. A subsequent oxalate precipitation step selectively concentrated >98% of extracted REE by ∼7-12 times compared to raw MSWIA. Waste byproducts were upcycled to synthesize zeolites, resulting in an overall solid waste volume reduction of ∼80% and heavy metal immobilization efficiency of ∼75% with negligible leaching, bringing the dual benefits of REE recovery and waste management. This work serves as a pioneer study in REE recovery from an emerging source and provides system level insights on the practicality of a simple three-step treatment system. Compared to existing literature, this system features a low chemical/energy input and a light environmental footprint.

Study on the fate of phosphorus, fluorine and chlorine in sludge during incineration

Sludge is often incinerated to achieve complete harmlessness and maximum capacity reduction, but the utilization of P (phosphorus) and the environmental pollution of F (fluorine) and Cl (chlorine) released from sludge incineration are usually ignored. In this paper, a series of experiments were employed to inquire into the conversion of various forms of P and the release of various forms of F and Cl after sludge incineration at different temperatures; the agriculture application prospect of P in sludge incineration ash and the environmental pollution caused by the release of F and Cl were discussed. The results show that P in sludge mainly exists as NAIP (non-apatite inorganic P) which biological effect was small. In the process of sludge incineration, InorgP (inorganic P) began to volatilize at 900 ℃, and the remaining P in sludge ash was 30.96 % at 1100 ℃. The forms of P in sludge incinerated at different temperatures varied considerably: a small amount of OrgP (organic P) in the sludge was converted into InorgP at 400 ℃; with the increase of incineration temperature, AP (apatite P) increased gradually, with 3.00 × 103–7.98 × 103 g/t in sludge ash at 700–1100 ℃. At 900 ℃, the content of AP in incineration ash was the highest, accounting for 58.98 % of Total P, which was the most suitable for slow-release phosphate fertilizer. At 600–1100 ℃, more Cl release, with a release rate of 50.61–92.70 %, among which the Cl for HCl (ClHCl) was 1.64 × 103–1.95 × 103 g/t at 700–1100 ℃. The F release rate was 1.52–37.39 %, among which the InorgF (inorganic F: mainly refers to F in HF and SiF4) was 1.13–27.91 g/t at 300–1100 ℃, the release amount of OrgF (organic F) was 1.59–1.86 g/t at 600–800 ℃. It can be seen that after incineration above 700 ℃, the sludge incineration ash may be used as a slow-release phosphate fertilizer, the release of Cl has greater environmental pollution and instrument corrosion than that of F, and the exhaust gas from sludge incineration cannot be discharged directly into the atmosphere.

Development of Eco-Mortars with the Incorporation of Municipal Solid Wastes Incineration Ash.

The cement sector is the second largest contributor to anthropogenic CO2 emissions, and several efforts have been made to reduce its environmental impact. One alternative that has gained interest in recent years involves the use of municipal solid waste incineration (MSWI) bottom ash (BA) as clinker/cement replacement. This paper studies the application of MSWI BA in three different ways: (i) aggregate (0 to 100 v/v %), (ii) partial binder substitute (0 to 30 v/v %), and (iii) filler (5 v/v %). It stands out for its approach in characterizing seven distinct BA particle sizes and for the development and analysis of eco-cement mortars with only mechanically pre-treated BA. Hardened state properties showed that the use of BA as aggregate leads to deterioration and efflorescence formation on the surface of the mortars, making this application unfeasible. The replacement of 15 v/v % of OPC (Ordinary Portland Cement) by BA and the use of finer (<63 μm) BA as filler caused a decrease in the compressive strength of the mortar, from 15.8 to 9.3 and 11.0, respectively. However, these materials are suitable for use in walls where the minimum required mechanical resistance is 5 MPa. Furthermore, these mortars demonstrated resilience against freeze-thaw cycles and even exhibited increased compressive strength after 25 cycles. Thus, this work showed that MSWI BA can be used as an OPC substitute (up to 15 v/v %) and as a filler, promoting circular economy principles and reducing CO2 emissions related to the construction industry.

Prediction of ash fusion temperatures of municipal solid waste incinerator ash based on support vector regression

The ash fusion temperatures (AFTs) of the municipal solid waste incinerator (MSWI) ash and slags is the main indicator to judge its slagging characteristics. Support vector regression (SVR) algorithm is more appropriate for creating an AFT prediction model than the classic regression method because it can adjust to a wider range of ash sample types in a wider range of areas by avoiding underfitting and overfitting. In this paper, SVR prediction models for the deformation temperature (IDT), softening temperature (ST), hemisphere temperature (HT), and flow temperature (FT) of ash are constructed using the ash chemical composition and AFTs dataset of coal ash and biomass ash and other ash. The AFTs of fly ash, bottom slag, and other ash in the municipal solid waste incinerator are predicted. With average relative errors of 1.98 % and 3.56 % and maximum relative errors of 5.21 % and 5.2 %, respectively, the results demonstrate that ST and FT have greater prediction accuracy. IDT and HT both provide poor predictions, with maximum relative errors of 14.08 % and 9.36 %, respectively, and average relative errors of 10.06 % and 5.95 %, respectively. Additionally, the impact of removing various numbers of outlier samples from training data on prediction accuracy, and the impact of test sample measures, such as ash composition analysis and AFTs determination, on prediction accuracy are analyzed and examined.

Medical Waste Incineration Ash Waste: Impact On Environmental Health And Its Potential To Be Used For Paving Blocks

ABSTRACT : It is known that medical waste has increased in recent years due to the Covid-19 pandemic, which was followed by an increase in ash from burning medical waste processing using incinerators. The objective of this study is to determine the impact of using medical waste incineration ashes on health and the environment, as well as the potential for using solidification techniques to make the ash into paving blocks. The ash used was obtained from a medical waste processing facility in Surakarta, Indonesia's Central Java. The test object was created using seven different combinations of ash, sand, and cement with a water-cement ration of 0.5 and cured for 28 days. The optimum compressive strength condition was determined as the basis for the composition of medical waste incineration ash as a mixture of paving block raw materials, which was then tested for the content of heavy metal compounds using the SNI 8808: 2019 method. According to research, the ash from medical waste incineration contains heavy metal compounds such as Pb, Ni, Cu, and Cd and has the potential to be used as a mortar mixture. Six of the seven mortar compositions with the addition of incineration medical waste ash met the compressive strength requirements of SNI 03-0691-1996 for category D paving blocks to be used in parks and other places.

The Sequential Extraction of Municipal Solid Waste Incineration Bottom Ash: Heavy Metals Mobility and Sustainable Application of Ashes

This manuscript focuses on the sustainable utilization of municipal waste incineration ashes in construction, taking into account their substantial concentration of beneficial elements and the potential environmental pollution caused by the leaching of toxic elements due to naturally occurring processes. To assess heavy metal mobility in ashes, a sequential extraction method based on the European Community Bureau of Reference (BCR) was applied. It enables the determination of heavy metal fractions and provides valuable insights into their potential environmental impact and bioavailability. More than 80% of Cd, and Zn, and over 75% of Cu, exhibited strong associations with the most mobile exchangeable fraction, while over 60% of Al and Fe were predominantly bound to reducible. The distribution of As and Cr was relatively balanced between exchangeable and oxidizable fractions, whereas 100% of Pb was exclusively associated with oxidizable fractions, indicating immobilization of this element in the ash. The calculated Risk Assessment Codes and Individual Contamination Factors indicated a quite high to very high risk level for the element’s mobility and environmental contamination. For elements like Pb, Cd, Cu, and Zn, higher concentrations in the samples are associated with higher overall environmental risk. For elements like As and Cr, higher concentrations in the samples are associated with lower overall environmental risk. Studied ash exhibits potential as a resource, but equally it demands rigorous environmental management to ensure responsible utilization. The observed metal mobilization underscores the necessity for stringent containment and treatment measures to mitigate the risk of environmental contamination.

Biotechnological strategies to recover value from waste

The demand on especially clean energy metals is growing exponentially creating a clear need to diversify the metals supply. Metal recovery from various waste deposits could be one solution to provide needed metals for the society and at the same time reduce the environmental effects of waste. Bioleaching has been commercially applied for the recovery of valuable metals from sulfidic ores, tailings and metallurgical side streams. Bioleaching approaches are still at laboratory scale for other waste streams, such as waste incineration ash, metallurgical slags and electronic waste. Adapted bioleaching strategies have been suggested for industrial and consumer metal-containing waste streams to overcome the challenges with alkalinity, heterogeneity, toxic contents, and the lack of sulfur and iron source. Integration of bioleaching with other technologies as well as integration of target waste with other material streams is one means to improve the process performance to reach higher metal yields and kinetics. Bioleaching has shown potential to decrease energy consumption and carbon footprint compared to more conventional technologies in commercial scale, which increases its attractiveness as a future technology choice.

Legacies of Pre-1960s Municipal Waste Incineration in the Pb of City Soils.

A 1937 street map of Durham, North Carolina, located four city-run waste incinerators that we recognized to be sites of contemporary city parks. We obtained city permission to sample three park's soils, developed a sampling design for geospatial mapping of hypothetical incinerator-ash contamination of park soils, and queried online Durham newspapers to understand histories of incinerator operations, ash disposal, and incinerator-to-park conversions. In 2021-2022, seven decades after parks were created, two parks had soil-Pb > 400 mgPb/kg, EPA's threshold for safe soil in play areas. At Walltown Park, six of 97 surface samples ranged from 416 to 1338 mg Pb/kg within meters of a basketball court and a park path. East Durham Park had a hectare-sized area where 12 samples averaged 1294 mgPb/kg (median 1335 mg/kg). Engineering surveys of United States and Canadian cities in 1941 and 1958 suggest that half incinerated solid wastes. Many records describe how incinerator ash was dumped with little regard for health or environmental hazards. Legacy soil contaminations of incinerator ash can be identified, as we have done in Durham, from historical records of city-waste incinerator operations, online access to newspaper archives that describe incinerator-to-park conversions, and a XRF to screen for soil-Pb contamination.

Microplastics in waste management systems: A review of analytical methods, challenges and prospects

Numerous studies have reported the presence of microplastics (MPs) in waste collection and disposal systems. However, current scientific studies on measuring MP occurrence in a waste management context are not comparable due to a lack of standardized methodologies. Consequently, the impact of MPs on ecosystems and human health remains largely unclear. To address the inconsistencies, present in published studies, this review thoroughly examines sample preparation techniques for transfer stations, landfill leachate, recycling, compost, and incineration ash samples. Furthermore, various analytical approaches such as flotation, filtration, and organic matter digestion, as well as morphological categorization, identification, and quantification, are subsequently rigorously assessed. The benefits and limitations of each methodology are evaluated to facilitate the development of accurate and effective methods for detecting and characterizing nanoplastics. Recent research suggests that plastic recycling and composting facilities are the primary environmental sources of microplastic pollution among different waste treatment methods. The most prevalent microplastic types discovered in waste management were polyethylene (PE) and polypropylene (PP), with fragment and fiber being the most frequently reported morphologies. The review highlights a number of tactics that could be integrated into the methodology development for detecting microplastics in waste management systems (WMS), ultimately leading to better consistency and reliability of data across different studies. In essence, this will advance our comprehension of potential risks associated with microplastics.

Microplastic Pollution Prevention: The Need for Robust Policy Interventions to Close the Loopholes in Current Waste Management Practices.

Plastic materials that are less than 5 mm in size are defined as Microplastics (MPs). MPs that are intentionally produced are called primary MPs; however, the most abundant type in the environment consists of the remainder created by the fragmentation of large plastic debris through physical, chemical, and oxidative processes, which are called secondary MPs. Due to their abundance in the environment, poor degradability, toxicological properties, and negative impact on aquatic and terrestrial organisms, including humans, MP pollution has become a global environmental issue. Combatting MP pollution requires both remediation and preventive measures. Although remediation is a must, considering where the technology stands today, it may take long time to make it happen. Prevention, on the other hand, can be and should be done now. However, the effectiveness of preventive measures depends heavily on how well MP escape routes are researched and understood. In this research, we argue that such escape routes (rather, loopholes) exist not only due to mismanaged plastic waste, but also due to cracks in the current waste management systems. One known MP loophole is facilitated by wastewater treatment plants (WWTP). The inability of existing WWTP to retain finer MPs, which are finally released to water bodies together with the treated wastewater, along with the return of captured larger MPs back to landfills and their release into the environment through land applications, are a few examples. Organic waste composting and upcycling of waste incineration ash provide other MP escape pathways. In addition, it is important to understand that the plastics that are in current circulation (active use as well as idling) are responsible for producing MPs through regular wear and tear. Closing these loopholes may be best attempted through policy interventions.

Effect of waste-derived soil amendments on mitigating leaching impacts from municipal solid waste incineration (MSWI) ash

This study explores modifying a sandy soil with a low solid to liquid partitioning coefficient (Kd) by adding amendments including iron-rich industrial slag byproducts and biochars, which contain sorption sites for trace metals present in MSWI ash leachate (notably Sb, cited as a concern for reuse applications). Kd values for Sb were determined for the sandy soil to be as low as 1.6 ± 0.1 L/kg. With amendments, Kd values varied from 1.4 ± 0.2 L/kg for combined ash leachate exposed to a blend of sandy soil and 20% iron slag, to 990 L/kg for combined ash leachate exposed to a blend of sandy soil and 20% magnetic solids. A blend of 20% magnetic solids showed orders of magnitude increase beyond 100% sandy soil. The biochars showed limited capacity to reduce leached Sb in the ash-derived leachate, which is likely due to negative surface charges of the biochars and Sb at basic pH. A risk assessment (US EPA IWEM) performed using experimental Kd for each blend suggests that using soil amendments could reduce leached concentrations at points of concern, which could open additional avenues for ash reuse.

Efficient anaerobic digestate valorization: Nutrient recovery strategy for enhancing soil fertility in arid agricultural regions

Efficient nutrient cycling in agroecosystems is essential for sustainable agriculture, and the utilization of waste products from various industries can contribute to this process. In this study, we investigated the potential of using anaerobic digestate from food industry waste (sugar beets and food waste) as a nutrient source for fertilizer production. Digestates were sanitized using a mixture of inorganic acids (H2SO4 and H3PO4) or alkaline (KOH), with acidic hydrolysate yielding a higher concentration of amino acids (1981 mg/L) compared to alkaline (186 mg/L). The acidic hydrolysate was centrifuged, and the liquid fraction was used to create a foliar fertilizer. The solid fraction, acidic hydrolysate, sewage sludge incineration ash, and additives (ammonium nitrate, urea with urease inhibitor) were employed to formulate three granular fertilizers. Nitrogen balances were analyzed using Sankey charts for each fertilizer formulation. The highest nitrogen losses (45.90 kg N/1 kg formulation) were recorded in the production of fertilizer containing ammonium nitrate. The fertilizers' effectiveness was evaluated through preliminary wheat germination tests. The highest yields observed for the foliar fertilizer (1% dose) and granular with the addition of urea with a urease inhibitor (20% dose) groups, where fresh sprout mass was approximately 18% and 23% higher than the control, respectively. These findings demonstrate the potential of using anaerobic digestate from food industry waste for nutrient recycling in agroecosystems, contributing to sustainable agriculture.

Viability Study on Fly Ash and Bottom Ash from Combustion Waste

The substitution or addition of new supplementary cementitious materials (SCM) in the production of variety of construction materials has gained much interest. One of the examples of SCM is incineration ash which consist of fly ash (FA) and bottom ash (BA) which are the residues from the ignition of biomass and can brings applicable ecological advantages. However, the properties of this new materials need to be investigated to ensure its full potential can be developed. Therefore, this study is initiated to identify the characteristics of incineration ash from local source in Malaysia. To identify the elemental components of ashes, most widely method was adopted which is using X-Ray Fluorescence (XRF). The quantity of unburned carbon in fly ash is measured by loss on ignition, which has a major influence on the product’s characteristics. In addition, specific gravity and density were also determined and comparison has been made with cement. In this study it was found out that XRF results shows that both FA and BA consist of the same mineral composition with OPC majorly in silica, aluminium, calcium, and iron which makes is suitable to be used in the concrete. For LOI, the value for BA is much higher compared with FA due to the amount of unburnt carbon in its original compositions and the incomplete burning due to insufficient contact time in the furnace. Based on the result obtained for LOI, the average LOI value for FA and BA is 17.33 % and 44.67 %, respectively. As expected, for the specific gravity and density, FA having the lowest specific gravity and density. The density obtained for FA is 755 kg/m3 and for BA is 593 kg/m3. Overall, the use of incineration ash can be fully investigated by exploring other parameter that influence the performance of construction materials.