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This study explores the current state-of-the-art in the detoxification and valorization of solid residues from municipal solid waste incineration (MSWI), especially fly ash, using plasma vitrification. The principles and advances in hazardous material elimination, resource recovery, and system integration using plasma vitrification for MSWI fly ash are identified. The global production and the characteristics of MSWI fly ash are first reviewed. Then, the features and principles of plasma technologies used for MSWI fly ash treatment from the thermodynamic and physical aspects are provided. The mechanisms of detoxification of MSWI fly ash from the perspectives of dioxins destruction and metal separation by plasma vitrification are also discussed. Moreover, the recovery methods of valuable elements for vitrified slag are introduced. Finally, the improvement pathways of plasma vitrification processes from the domains of engineering performance, environmental impact, and economic viability are suggested. [ABSTRACT FROM AUTHOR]

In this study, a proposed integrated high-gravity technology for air pollution control, CO 2 capture, and alkaline waste utilization was comprehensively evaluated from engineering, environmental, and economic perspectives. After high-gravity technology and coal fly ash (CFA) leaching processes were integrated, flue gas air emissions removal (e.g., sulfate dioxide (SO 2), nitrogen oxides (NO x), total suspended particulates (TSP)) and CO 2 capture were studied. The CFA, which contains calcium oxide and thus, had high alkalinity, was used as an absorbent in removing air pollution residues. To elucidate the availability of technology for pilot-scale high-gravity processes, the engineering performance, environmental impact, and economic cost were simultaneously investigated. The results indicated that the maximal CO 2 , SO 2 , NO x , and TSP removal efficiencies of 96.3 ± 2.1%, 99.4 ± 0.3%, 95.9 ± 2.1%, and 83.4 ± 2.6% were respectively achieved. Moreover, a 112 kWh/t-CO 2 energy consumption for a high-gravity process was evaluated, with capture capacities of 510 kg CO 2 and 0.468 kg NO x per day. In addition, the fresh, water-treated, acid-treated, and carbonated CFA was utilized as supplementary cementitious materials in the blended cement mortar. The workability, durability, and compressive strength of 5% carbonated CFA blended into cement mortar showed superior performance, i.e., 53 MPa ±2.5 MPa at 56 days. Furthermore, a higher engineering performance with a lower environmental impact and lower economic cost could potentially be evaluated to determine the best available operating condition of the high-gravity process for air pollution reduction, CO 2 capture, and waste utilization. Image 1 • Chemical properties and calcium leaching kinetic of coal fly ash were described. • Simultaneous air emission reduction from exhausted gas in a RPB was achieved. • Efficacy of wastes utilization as SCM in cement mortar was evaluated. • Best available operating conditions were identified by 3E triangle model. [ABSTRACT FROM AUTHOR]

In this study, an innovative valorization of petroleum coke fly ash as supplementary cementitious materials in blended cement mortars was investigated. To stabilize and upgrade the properties of fly ash, accelerated carbonation was performed to convert calcium oxide and other calcium-bearing species in fly ash into calcium carbonate. The results indicated the achievable carbonation conversion of fly ash was approximately 40%. The changes in physico-chemical properties of fly ash before and after carbonation also were examined by thermal analysis and Fourier-transform infrared spectroscopy. Several material function tests of blended cement mortars with carbonated fly ash, including workability, strength development and durability, were carried out. We found that the strength of cement mortars blended with carbonated fly ash was 20% higher than that of original Portland cement. A mathematical model on the strength development kinetics was developed to elucidate the relationship between mineral compositions and curing times. The carbonated fly ash could facilitate the hydration reaction in blended cement, as well as accelerating the strength development of blended cement by 28%. This study revealed the possibility of establishing a waste-to-resource supply chain by connecting CO 2 mineralization with fly ash valorization as cementitious materials. [ABSTRACT FROM AUTHOR]

A high-gravity carbonation process was deployed at a petrochemical plant using petroleum coke fly ash and blowdown wastewater to simultaneously mineralized CO2 and remove nitrogen oxides and particulate matters from the flue gas. With a high-gravity carbonation process, the CO2 removal efficiency was found to be 95.6%, corresponding to a capture capacity of 600 kg CO2 per day, at a gas flow rate of 1.47 m3/min under ambient temperature and pressure. Moreover, the removal efficiency of nitrogen oxides and particulate matters was 99.1% and 83.2%, respectively. After carbonation, the reacted fly ash was further utilized as supplementary cementitious materials in the blended cement mortar. The results indicated that cement with carbonated fly ash exhibited superior compressive strength (38.1 ± 2.5 MPa at 28 days in 5% substitution ratio) compared to the cement with fresh fly ash. Furthermore, the environmental benefits for the high-gravity carbonation process using fly ash were critically assessed. The energy consumption of the entire high-gravity carbonation ranged from 80 to 169 kWh/t-CO2 (0.29-0.61 GJ/t-CO2). Compared with the scenarios of business-as-usual and conventional carbon capture and storage plant, the economic benefit from the high-gravity carbonation process was approximately 90 and 74 USD per ton of CO2 fixation, respectively. [ABSTRACT FROM AUTHOR]

Green infrastructure practices could provide innovative solutions for on-site stormwater management and runoff pollution control, which could relieve the stress of nonpoint pollution resulting from heavy rainfall events. In this study, the performance and cost-effectiveness of six green infrastructure practices, namely, green roofs, rain gardens, pervious surfaces, swales, detention basins, and constructed wetlands, were investigated. The comprehensive performance evaluation in terms of the engineering performance, environmental impact, and economic cost was determined in the proposed engineering–environmental–economic (3E) triangle model. The results revealed that these green infrastructure practices were effective for stormwater management in terms of runoff attenuation, peak flow reduction and delay, and pollutant attenuation. It was suggested that for pollution control, detention basins can efficiently reduce the total suspended solids, total nitrogen, total phosphorus, and lead. The implementation of detention basins is highly recommended due to their higher engineering performance and lower environmental impact and economic cost. A case study of a preliminary cost–benefit analysis of green infrastructure practice exemplified by the Pearl River Delta in China was addressed. It suggested that green infrastructure was cost-effective in stormwater management in this area, which would be helpful for sustaining healthy urban watersheds. [ABSTRACT FROM AUTHOR]

This paper provides an overview of the interrelationships between tourism and sustainability from a cross-disciplinary perspective. The current challenges and barriers in the tourism sustainability, such as high energy use, extensive water consumption and habitat destruction, are first reviewed. Then the key cross-disciplinary elements in sustainable tourism, including green energy, green transportation, green buildings, green infrastructure, green agriculture and smart technologies, are discussed. To overcome the challenges and barriers, a few implementation strategies on achieving sustainable tourism from the aspects of policy/regulation, institution, finance, technology and culture are proposed, along with the framework and details of a key performance indicator system. Finally, prospects of the potential for tourism to contribute to the transformative changes, e.g., a green economy system, are illustrated. This paper shine a light on issues of importance within sustainable tourism and encourage researchers from different disciplines in investigating the inter-relationships among community/culture, environment/ecology, and energy/water/food more broadly. [ABSTRACT FROM AUTHOR]

In this study, a proposed integrated high-gravity technology for air pollution control, CO 2 capture, and alkaline waste utilization was comprehensively evaluated from engineering, environmental, and economic perspectives. After high-gravity technology and coal fly ash (CFA) leaching processes were integrated, flue gas air emissions removal (e.g., sulfate dioxide (SO 2 ), nitrogen oxides (NO x ), total suspended particulates (TSP)) and CO 2 capture were studied. The CFA, which contains calcium oxide and thus, had high alkalinity, was used as an absorbent in removing air pollution residues. To elucidate the availability of technology for pilot-scale high-gravity processes, the engineering performance, environmental impact, and economic cost were simultaneously investigated. The results indicated that the maximal CO 2 , SO 2 , NO x , and TSP removal efficiencies of 96.3 ± 2.1%, 99.4 ± 0.3%, 95.9 ± 2.1%, and 83.4 ± 2.6% were respectively achieved. Moreover, a 112 kWh/t-CO 2 energy consumption for a high-gravity process was evaluated, with capture capacities of 510 kg CO 2 and 0.468 kg NO x per day. In addition, the fresh, water-treated, acid-treated, and carbonated CFA was utilized as supplementary cementitious materials in the blended cement mortar. The workability, durability, and compressive strength of 5% carbonated CFA blended into cement mortar showed superior performance, i.e., 53 MPa ±2.5 MPa at 56 days. Furthermore, a higher engineering performance with a lower environmental impact and lower economic cost could potentially be evaluated to determine the best available operating condition of the high-gravity process for air pollution reduction, CO 2 capture, and waste utilization., (Copyright © 2019 Elsevier Ltd. All rights reserved.)