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•Stabilization/Solidification (S/S) for hazardous materials was evaluated by life cycle assessment.•Sediment and municipal solid waste incineration fly ash remediation was studied ...with 17 S/S scenarios under five strategies.•Alternative binders and recycled materials reduced the overall environmental impacts.•This decision-support process could facilitate the design of sustainable remediation.
Proper management of hazardous materials arouses widespread environmental concerns due to its enormous ecological and health impacts. The development of green stabilization/solidification (S/S) technology for resourceful utilization of hazardous materials, as well as the immobilization of potentially toxic elements is of great scientific interests. Cement-based S/S is often considered a low-cost and highly efficient technology, but the environmental sustainability of a broad spectrum of S/S technologies has yet to be evaluated. Therefore, this study assessed the environmental sustainability of S/S technologies for managing two common types of hazardous wastes, i.e., contaminated marine sediment and municipal solid waste incineration fly ash (MIFA) by using life cycle assessment (LCA). A total of 17 scenarios under three strategies for sediment and two strategies for MIFA S/S technologies were comprehensively evaluated. The LCA results identified the most preferable S/S technology in each strategy. In particular, Scenario 1 (mixture of sediment with a small percentage of ordinary Portland cement and incinerated sewage sludge ash) of Strategy 1 (use as fill materials) would be the preferred option, as it reduces about 54% and 70% global warming potential compared to those of Scenarios 2 and 3, respectively. This is the first initiative for evaluating the environmental impacts of a wide range of recently developed S/S technologies using green/alternative binders for diverting hazardous wastes from disposal. The results can serve as a decision support for the practical application of the environmentally friendly S/S technology for sustainable remediation.
•Life cycle inventories of emergency MW disposal scenarios are established.•Key factors of movable disposal scenarios are identified via LCA.•Environmental impacts of five emergency disposal ...scenarios were compared.•Recommendations for the emergency management of MW disposal are provided.
The COVID-19 pandemic attracts concerns globally and leads to an exponential increase in medical waste generation, and disposal of medical waste is an urgent need for preventing the epidemic spread. Emergency disposal scenarios of medical waste generated during the COVID-19 pandemic require a systematic assessment to quantify their potential environmental impacts. The environmental impacts and key factors of three movable disposal scenarios (i.e. incineration disposal vehicle, movable steam and microwave sterilization equipment both followed by co-incineration with municipal solid waste) were quantified via life cycle assessment approach. Furthermore, the environmental impacts of three movable disposal and two co-incineration scenarios were compared via life cycle assessment by expanding system boundaries. The results show that co-incineration with municipal solid waste has the lowest environmental impacts due to environmental benefits produced by power generation, while co-incineration with hazardous waste is the highest due to the high energy consumption. Energy consumption (i.e. kerosene, electricity and diesel) are the key factors for three movable disposal scenarios. For movable steam and microwave sterilization equipment followed by co-incineration with municipal solid waste, power generation from incinerating disinfected medical waste has significant beneficial environmental impacts due to avoided impacts of electricity consumption. The recommendations for improvement of the emergency disposal and management of medical waste during the COVID-19 pandemic globally and other serious epidemic in the future are provided.
Selection of the most appropriate waste-to-energy technologies for distributed electricity generation is a complex and multi-criteria decision problem as it involves trade-off among conflicting ...criteria which have to be considered simultaneously. In this study, the Technique for Order of Preference by Similarity to an Ideal Solution (TOPSIS) with Entropy Weighted method is applied to select the optimal technology among the waste -to -energy technological options using the waste stream of Lagos, Nigeria. The results presented show that anaerobic digestion has been the best waste to energy technology solution for electricity generation in Lagos, followed by pyrolysis while incineration is seen as the worst preferred option of choice for energy generation applicability in standalone model. In order to maximally extract energy from waste in a sustainable, economical, and environmentally friendly manner, an integrated application of waste-to-energy technologies is also explored. It is found that the hybrid of anaerobic digestion, landfill gas recovery and pyrolysis give the most favourable results in terms of environmental benefits and electricity generation potential. It is also revealed that incineration technology either in the standalone or in the hybrid form is completely discouraged from being implemented in Lagos basically due to its high investment, operation and maintenance costs as well as its discouraging environmental image. Although, the case study in this paper is that of Lagos, Nigeria but the methodology presented could be used for any cosmopolitan city around the world.
•Selection of the most appropriate waste to energy technologies is performed.•TOPSIS technique with Entropy weighted method is applied for the selection.•Anaerobic digestion is the best WtE technology solution for electricity generation.•Incineration is the least preferred option of choice for energy generation applicability.•Hybrid of AD, landfill gas recovery and pyrolysis gave the most favourable results.
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•Life cycle assessment of WtE plant is performed for some selected cities in Nigeria.•We determine the Wte that best fit the cities in an environmentally sustainable way.•The LCA ...technique is based on ISO 14040/43 and Eco-indicator 99 methods.•Waste profile of each city is determined using population data obtained from NPC.•Greenhouse gas, acidification & dioxin potential of the WtE plants are determined.
In this paper, life cycle assessment (LCA) of waste to energy (WtE) treatment plants for electricity generation in twelve selected cities of Nigeria is studied with the aim of evaluating their electricity generation potential, global warming potential (GWP), acidification potential (AP) and dioxin/furan emission potential. The WtE plants are: landfill gas to energy (LFGTE), hybrid of incineration and anaerobic digestion (INC/AD) and hybrid of incineration and landfill gas to energy (INC/LFGTE). The benefits of the WtE plants are thereafter compared to the landfilling (waste management without intention of energy recovery) in each of the locations in order to determine the option that best fit the locations in an environmentally sustainable manner. To achieve this, the waste profile of each of the locations is determined using per capita waste generation and the population data obtained from national population commission (NPC). Some of the key results reveal that the hybrid of INC/AD is potentially viable compared to other methods in terms of GWP and ecosystem potential measured by AP. However, LFGTE technology is the best in terms of carcinogenic reduction potential measured by dioxin/furan emissions. The hybrid of INC/AD has the potential of reducing GWP in the range of 75.7–93.3% compared to land filling without energy recovery. Similarly, hybrid of INC/LFGTE provided a reduction in the range of 75.3–84.8% while LFGTE could reduce the GWP by 75%. This paper could serve as a source of scientific information for decision making on environmental sustainability in waste-to-energy projects in Nigeria.
•Mechanism analysis of municipal solid waste incineration (MSWI) has been narrated.•Numerical simulation method of the MSWI process is compared and discussed.•Coupling several software can produce ...customized simulation models based on actual process data.•Digital twin model construction for environmental protection requires artificial intelligence.
Determining the status of the municipal solid waste incineration (MSWI) process due to the composition variations of MSW, operational differences of the MSWI plants, and maintenance uncertainties of the incineration devices is difficult. Moreover, the optimal control algorithms developed off-line lack the support of the incineration mechanism. These conditions complicate the cost-effective operation of the MSWI plants. The development of customized numerical simulation models can simulate the incineration effects and obtain the extreme value of key process parameters to support its operational optimal control. This article aims to review the mechanical characteristics and numerical simulation methods of the MSWI process based on mechanical grates, thus providing support for the construction of a customized numerical simulation model and the realization of a digital twin system for the actual MSWI process. First, the mechanical characteristic of the MSWI process is comprehensively analyzed. Then, the numerical simulation method based on commercial and self-developed software is summarized and compared. Furthermore, the difficulties in creating customized numerical simulations and constructing digital twin models are discussed. Finally, the conclusion and research directions are established on the basis of the concluding ideas and specific commentaries. Results show that coupling several types of software can facilitate the creation of customized simulations based on actual process data. The development of an intelligent digital twin encounters several difficulties that must be highlighted because the combination of the numerical simulation model of the entire process can analyze the mechanism and the realization of matching the model with actual process data. The current study revealed that the digital twin model based on mechanical characteristics and numerical simulations by using actual process data and artificial intelligence technology could play a significant role in the safety and operation optimization of the MSWI process.
A novel medical-waste-to-energy design combining plasma gasification (treating medical waste) and municipal solid waste (MSW) incineration has been developed. In the integrated system, the syngas ...generated by the plasma gasification of medical waste is first burned and drives the gas turbine for power generation, subsequently, the gas turbine exhaust is taken to heat the live steam and feedwater of the MSW incineration plant, improving the power cycle of the incineration plant. Consequently, medical waste can be converted into electricity efficiently in the meantime of harmless management. The hybrid design was investigated by multiple approaches including energy analysis, exergy analysis, and economic analysis. It is found that the energy efficiency and exergy efficiency of medical-waste-to-electricity can reach up to 37.83% and 34.91% with a net total power of 4.24 MW yielded from medical waste, while the net power generated from MSW is considered fixed. Besides, the proposed medical-waste-to-electricity project has a short dynamic payback period of 3.75 years and the relative net present value can achieve 45,239.90 k$. These results demonstrate that the novel concept is efficient, feasible, and advantageous, which is promising to be implemented in the field of waste-to-energy.
•A novel medical-waste-to-energy design based on plasma gasification is proposed.•The medical-waste-based power process is integrated to an incineration power plant.•The fly ash collected from MSW incineration is treated together with medical waste.•The medical-waste-to-electricity efficiency can reach up to 37.83%.•The dynamic payback period is only 3.75 with a net present value of 45,239.90 k$.
•FE and SUR models analyse waste management policies from 14 European countries.•Landfill ban and deposit refund scheme correlated with decrease in landfill waste.•Landfill ban also associated with ...increase in energy recovery and recycling waste.•Landfill tax and deposit refund scheme correlated with decrease in waste generated.
Waste management policies aim to divert waste from lower positions on the waste hierarchy such as landfill and incineration to higher positions in the hierarchy such as energy recovery and recycling. However, empirical evaluations of such policies are scarce. This study highlighted the effect of waste management policies on the amount of waste treated with landfill, incineration, energy recovery and recycling by analysing a panel dataset consisting of 14 European countries and the period 1996 to 2018. Findings from a seemingly unrelated regression model suggest that the landfill ban is associated with a decrease in landfill waste, but an increase in incineration, energy recovery and recycling waste. The landfill tax is also correlated with an increase in energy recovery waste but, in contrast, it is associated with a reduction in incineration and recycling waste. Meanwhile, the deposit refund scheme is associated with a decrease in the amount of landfill waste. Concerning the effects on total waste generated, regression results from a fixed effects model indicate that the landfill tax and the deposit refund scheme are both correlated with a reduction in the amount of waste generated. These findings contribute to the scarce academic literature evaluating waste management policies and may better inform policy makers on their longer-term implications.
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•Inorganic acids found to remove more heavy metals than organic acids.•Washing of treated ash affects leaching profile and marine toxicity.•Raw ash shows lower marine toxicity as ...compared to treated ash, but inferior to concrete sand.•Raw ash displays dose & size dependent toxicity with human cell lines.
Sewage sludge bottom ash, which is the major fraction obtained from the incineration of sewage sludge was treated with various organic and inorganic acids for heavy metal removal, along with a comparative phosphate treatment for heavy metal fixation. Malonic acid, an organic acid, was found to remove heavy metals better as compared to nitric acid, a strong inorganic acid. The acid treated samples were further examined for heavy metal leaching, followed by marine toxicity/abnormality testing of the leachates, where acid treated and phosphate treated ash leachate displayed higher (with malonic acid proving to be most toxic) and similar toxicity profiles as compared to raw ash leachate respectively. Raw ash was tested for its leaching patterns at different liquid/solid ratios(L/S = 5 and 10), salinities and time points (24, 48 and 72 h), where the leaching was found to saturate at L/S = 5 and at 24 h with varied salinity effecting the leaching insignificantly. When raw ash was benchmarked against concrete sand for marine toxicity, a material commonly used for land reclamation, acute toxicity patterns were found to be mostly similar except in case of the sea urchin embryonic assay, where toxicity was detected, indicating the sensitivity of the assay to residual levels of heavy metals. The raw ash was also tested against human cell lines where it displayed size and dose-dependent toxicity. To enable the use of ash for environment applications such as coastal reclamation, appropriate treatments are required to minimize leaching of potential harmful contaminants and this study demonstrates the importance of post-treatment of ash on its subsequent toxicity to organisms.
•Both filterable and condensable PM2.5 from two waste incineration power plants were characterized.•Fe is the most abundant component of elements in filterable PM2.5, followed by Na, Ca, and ...Al.•Inorganic species are dominant in condensable PM2.5, accounting for 77–94%.
Compositions of filterable PM2.5 (FPM2.5) and condensable PM2.5 (CPM2.5) emitted from waste incineration power plant. Display omitted
Incineration technology is an effective treatment method for municipal solid waste (MSW). In this study, fine particulate matter emissions from two waste incineration power plants (WIPP) were characterized. Both filterable particulate matter (FPM2.5) and condensable particulate matter (CPM2.5) were collected using a direct sampling method. The FPM2.5 concentrations from stacks #1 and #2 in WIPP A were 0.87 ± 0.10 and 0.68 ± 0.19 mg/m3, respectively, and 3.30 ± 0.65 mg/m3 was measured at stack #3 in WIPP B. Fe was the most abundant elemental component in the FPM2.5, followed by Na, Ca, Al, and K. Ca2+, SO42−, Cl−, and NH4+ accounted for the largest fraction of the total detected water-soluble ions in the FPM2.5. In the CPM2.5, Na was the most abundant elemental component, followed by Ca, Mg, and K. The total detected water-soluble ions accounted for 22.2% and 27.3% of the CPM2.5 collected from stack #1 and #2, respectively. High concentrations of NH4+ and NO3− were found in CPM2.5, which could be derived from the escape of excessive NH3 in the denitrification unit and that of the NOx in the flue gas, respectively. Alcohols, aromatic compounds, and ketones were the major organic species in the CPM2.5. Both fly ash and bottom ash were collected from WIPP A. Ca was the dominant element, followed by K, Mg, Na, and Fe. The enrichment of elements in the fly ash and bottom ash were analyzed. The enrichment factors of most elements were higher than 1, except for the Ti and Sn in the bottom ash. The fly ash had a higher enrichment of Cd, As, and Ti than the bottom ash. In contrast, Cu, Ni, and Cr had higher enrichments in the bottom ash because of their low volatility.
In China, the co-incineration of municipal solid waste (MSW) with industrial organic solid waste (IOSW) is increasingly adopted. Compared with MSW, IOSW contains higher levels of sulfur (S) and ...chlorine (Cl), presenting significant challenges for controlling S/Cl emissions in MSW incineration plants. In this study, the impact of co-incinerating IOSW was investigated in a 500 t/d incinerator grate, focusing on the emissions and transformation behaviors of S/Cl. IOSW, with a consistent sulfur content of about 0.22 wt% and a more variable chlorine content averaging 0.53 wt%, contains over 40 % organic sulfur and >90 % organic chlorine, higher than in MSW. The results of co-incineration experiments showed that the median SO2 concentration in the flue gas was stable at 50 mg/m3, while HCl concentration decreased initially and then increased as the co-incineration ratio of IOSW rose from 20 % to 40 %. Furthermore, the concentrations of SO2 and HCl were not significantly influenced by wind flow but were positively affected by the rising furnace temperatures. Besides, the co-incineration ratio had minimal impact on sulfur in fly ash before deacidification, primarily derived from the gas stream. However, the (Na + K)/Cl ratio in fly ash progressively increased from 1.5 to 1.9, and the Ca content decreased from 0.35 % to 0.15 % as the co-incineration ratio rose to 40 %, indicating more chlorine migration into the fly ash at higher co-incineration rates. This research offers essential guidance for effectively controlling pollutant emissions during the co-incineration of IOSW, specifically the S/Cl pollutants.
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•The transformation behavior of S/Cl was studied during co-incinerating MSW with IOSW.•The S/Cl of IOSW mainly was in the form of organic species.•Co-incineration has a large impact on HCl emission but a negligible effect on SO2.•The high furnace temperature and the co-incineration ratio promote HCl emission.•The ratio of Cl from condensation in ash improved as the co-incineration ratio increased.
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