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Reasonable treatment of large amounts of sludge excavated from landfills has gained increasing attention due to the diminishing availability of landfill space in China. In this study, five landfill sludge (LS) treatment technologies using life cycle assessment (LCA) and life cycle cost (LCC) were investigated, i.e., co-incineration in coal-fired power plants (CFPP) and waste incineration power plant (WIPP), co-processing in cement kiln, bricks production, and sintering ceramsite. The LCA results demonstrate that sintering ceramsite outperforms other technologies and LCC results indicate sintering ceramsite also provides the highest economic benefit ($869.94). To further enhance environmental and economic performances of the LS treatment, the substitution of coal with natural gas and biomass can reduce Energy Conservation and Emission Reduction (ECER) index by 74% and 98%, respectively. This substitution can increase economic returns by 24% and 26%, respectively. Furthermore, national-level economic benefit and carbon emission reduction potential of different LS treatment technology alternative scenarios were assessed. Results display that a combination of 50% CFPP, 25% bricks, and 25% ceramsite (biomass) offers the highest economic gain, which is 3.02 times that of 50% CFPP and 50% cement (original case). Conversely, the replacement of 25% brick with 25% cement in the above combination result in the lowest carbon reduction, which is 9.35 times that of the original case. [ABSTRACT FROM AUTHOR]

Paper mill sludge (PMS) is featured with a high content of cellulose and hemicellulose, and using its characteristics to make paperboard can achieve a high-value utilization of PMS, which has attracted growing interest. In this study, currently prevalent landfill, incineration technologies (generating heat and electricity by incineration), and three paperboard technologies (medium density fiberboard, pulp board, and corrugated paper) were evaluated and compared via life cycle assessment (LCA) and life cycle costing (LCC) methods. LCA results show that the PMS-to-pulp board outperforms others with an energy conservation and emission reduction (ECER) value of − 2.86 × 10−8, while the landfill exhibits the highest overall environmental impact with an ECER value of 4.80 × 10−9. LCC results reveal that the PMS-to-pulp board delivers the highest economic profit with $257.357, while the landfill is the lowest with $ − 35.63. The PMS paperboard technologies are more economically friendly than the incineration technologies due to additional electricity/steam consumption during the PMS pre-drying process in incineration. In addition, different scenarios were set up to explore national GHG emission reduction potential by increasing paperboard technologies application rate and reducing the proportion of landfill and incineration. The scenario analysis suggests that replacing 90% of landfill and incineration ratio with PMS paperboard technologies could tremendously improve the overall emission reduction performance with − 9.08 × 1010 kg CO2 eq. This result indicates that the PMS treatment technology transformation has a significant favorable impact on the achievement of the "carbon neutrality" target. [ABSTRACT FROM AUTHOR]

Harmless disposal and reutilization of electroplating sludge (ES) attract growing interests due to the high content of heavy metals, which requires economical-affordable and environmentally friendly processing technologies. Main reutilization alternatives in China, i.e., acid leaching, bioleaching, smelting, ironmaking blast furnace co-processing (IBFC), and cement kiln co-processing (CKC), were evaluated and compared via life cycle assessment (LCA) and life cycle costing (LCC) methods. In addition, the heavy metal recovery potential of these scenarios was also evaluated to focus on the sustainable use of metal resources. LCA results show that acid leaching outperforms other scenarios due to the environmental benefits originating from recovering heavy metals, while smelting exhibits the worst due to high energy consumption. The environmental contribution analysis reveals that the product nickel sulfate has a significant positive impact on acid leaching and bioleaching scenarios, and energy consumption is the key factor for smelting, IBFC, and CKC. LCC results show that bioleaching outperforms others, while CKC performs the worst because only inorganic materials are utilized. Bioleaching has the lowest externality cost while CKC has the highest. The heavy metal recovery assessment indicates that bioleaching exhibits the greatest potential with recovery rates of 99%, 99%, 93%, 96%, and 95% for Cu, Cr, Ni, Zn, and Fe, respectively. In contrast, the target heavy metal recovery rate for both acid leaching and smelting is 93%. Acid leaching and bioleaching scenarios are more advantageous from a comprehensive comparison. [ABSTRACT FROM AUTHOR]

Food waste (FW) treatment has attracted increasing attention since waste classification occurred in China. Analyzing the environmental and economic impacts of different FW treatment technologies is required. In this study, four FW treatments, i.e., anaerobic digestion, black soldier fly (BSF) bioconversion, composting, and landfill, were evaluated using life cycle assessment (LCA) and life cycle cost (LCC). LCA results show that anaerobic digestion outperforms the other technologies, while LCC results indicate anaerobic digestion has the lowest economic benefits ($5.16) and landfill has the highest ($14.22). Bioconversion has the highest product revenue ($37.98). FW anaerobic digestion followed by treating digestate and waste crude oil was employed to investigate the environmental differences between waste classification and mixed incineration. Digestate gasification and conversion of waste crude oil to biodiesel are found to be environmentally friendly, and waste classification outperforms mixed incineration. Furthermore, we explored national-level environmental emission reduction with anaerobic digestion as the dominant technology via increasing resource utilization rate and applying household FW disposers. Results display that a 60% resource utilization rate decreases the overall environmental impact by 36.68% compared with current situation, and treating household FW separately at the source can further lead to emission reduction. This study provides a reference for selecting FW technologies for countries worldwide from environmental and economic perspectives, as well as a direction of resource utilization for how to reduce environmental emissions from treating the total FW produced by all humanity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Village, town and county models with three gasification scales were compared. • The environmental impacts and economic cost of transportation were considered. • The overall environmental impact of county model is the lowest. • Town model delivers the lowest economic cost in three models. • Waste sorting was considered in scenario analysis via LCA and LCC. The dispersed sources and inconvenient transportation of rural domestic waste (RDW) lead to difficult centralized treatment. Gasification is suitable for decentralized waste treatment, which can effectively avoid RDW long-distance transportation and reduce dioxin emissions compared with small-scale incineration. Hence, economically-affordable and environmentally-friendly RDW treatment models with different gasification scales are required, and village, town and county models were compared via life cycle assessment (LCA) and life cycle cost (LCC) methods in this study. Furthermore, scenario analysis investigated waste sorting based on two food waste (FW) treatment technologies, different FW separate collection efficiency, and electricity recovery to explore the environmental and economic improvement potentials of three models. LCA results show that electricity consumption and direct emissions are significant contributors to environmental impacts, and the county model outperforms village and town models. Moreover, transportation accounts for 6% of the overall environmental impact in the county model. Scenario analysis reveals that waste sorting and electricity recovery can reduce the overall environmental impact by 29% to 146% for three models. LCC results demonstrate that the town model delivers the lowest economic cost, while the village model is the highest. In scenario analysis, resource utilization of FW and electricity recovery of other waste exhibit promising economic benefits. The findings provide comprehensive references for sustainable RDW treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Quantifying the environmental and economic impact of IOMS on sludge treatment. • The sludge treatment via IOMS pretreatment reduce the ECER values by 56%-76%. • Further processing IS to produce ceramsite can enhance resource utilization. • Assessing the environmental and economic impacts of provincial IOMS replication. As a new technology for accurate utilization of sludge resources, sludge inorganic–organic matter separation (IOMS) has attracted wide attention. This study examined the impact of this pretreatment on environmental and economic performance of sludge composting and incineration using life cycle assessment (LCA) and whole life costing (WLC). LCA results indicated that IOMS pretreatment reduced the energy conservation and emission reduction (ECER) values of composting and incineration by 56 % and 76 %, respectively. Meanwhile, WLC exhibited that IOMS pretreatment could cut the break-even year of incineration from 11 years to 4 years. The combination of organic sludge incineration/composting with inorganic sludge sintering ceramsite reveals excellent environmental and economic performance. The application optimization hypothesis analysis of these two routes in various provinces of China indicates that Jiangsu has the greatest development potential and should become a major promotion region. [ABSTRACT FROM AUTHOR]

• 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. [ABSTRACT FROM AUTHOR]

Sludge incineration attracts increasing interests in China. Different sludge incineration modes, incinerator types, auxiliary fuel and sludge drying heat sources can cause various energy, environmental and economic performances. In this study, seven sludge incineration technologies (i.e. , rotary kiln incineration with coal or natural gas fuel, fluidized bed incineration with natural gas or biomass fuel, co-incineration in coal-fired power plant (CFPP), and co-incineration in waste-incineration power plan (WIPP) by electric drying or steam drying) were evaluated and compared via energy flow analysis (EFA), life cycle assessment (LCA), and life cycle cost (LCC) methods. EFA results show that energy utilization efficiency of individual incineration without full utilization of waste heat is lower than 28%. LCA results show that comprehensive environmental indicator of coal and natural gas are approximately 100 times as large as biomass. For different drying heat sources, steam instead of electricity shows superior environmental impact. LCC results demonstrate that individual incineration technologies are 2–4 times that of co-incineration technologies in investment cost. The results of decision alternative ratia evaluation showed that co-incineration in CFPP is the best in seven technologies, followed by co-incineration in WIPP with steam drying. • Seven sludge incineration technologies were evaluated from energy, environment and economy. • Effect of incinerator type and auxiliary fuel on individual incineration were compared. • Co-incineration with electric drying and steam drying was compared. [ABSTRACT FROM AUTHOR]

• Four IFA reuse technologies are compared with the landfill option using LCA and LCC. • IFA heavy metals transfer coefficient model is establish using MFA. • Externality costs as environmental and social costs are estimated to reveal 'true' costs of technologies. • IFA-to-ceramsite is preferred option overall. • Waste disposal subsidies are crucial for IFA reuse technologies to be economic feasible. Harmless disposal and reutilization of municipal solid waste incinerator fly ash (IFA) attract growing interests due to the gap between increasing IFA generation and limited landfill space. Therefore, an economical-affordable and environmentally friendly approach to deal with IFA is required. Herein, major IFA reutilization technologies in China (IFA-to-cement, glassy slags, rock wool, and ceramsite) were evaluated and compared with the landfill using life cycle assessment (LCA) and environmental life-cycle costing (eLCC). Prior to assessments, material flow analysis (MFA) was used to establish a heavy metal transfer coefficient model. LCA results indicate IFA-to-cement and IFA-to-ceramsite outperform others while eLCC results show that IFA-to-ceramsite and IFA-to-rock wool are preferred, breaking even at years 3 and 5 compared to IFA-to-cement (new plant) at year 11. To reveal true costs of reutilization technologies, whole life costing (WLC) was applied to include externality costs via monetizing emissions. Major pollutants contributed to externality costs of these technologies were identified. IFA-to-ceramsite and IFA-to-rock wool technologies remain preferred with payback time as 4 and 6 years respectively. A scenario analysis suggests that replacing sintering aids with polluted soil and Sec-FA recovery could further improve the overall performance of IFA-to-ceramsite option. Policy scenario analysis reveals that corporate income tax and environmental protection tax have negligible impacts but waste disposal subsidy is vital for IFA reutilization technologies being economic feasible even without externalities. [Display omitted] [ABSTRACT FROM AUTHOR]

Straw management is extremely challenging, and irrational treatment can cause environmental pollution and affect the development of a circular economy in agriculture. The high-value utilization of agricultural straw as an important pathway to promote circular economy and achieve carbon neutrality goals has attracted much attention. Herein, the environmental and economic performance of the main straw-based fuel (straw-to-biochar, ethanol, and biogas) and material (straw-to-board and paper) utilization scenarios in China were compared from a life cycle perspective. This study is based on data from the eFootprint platform and the China Life Cycle Database. The results show that straw production for fuel has a better environmental performance than the production of materials option for water use, acidification potential, eutrophication potential, and respiratory inorganics. Utilizing straw to produce fuels or materials can reduce greenhouse gas emissions by 155–1296 kg CO2 eq. and decrease primary energy consumption by 8949–31270 MJ. Straw-to-board has the worst energy conservation and emission reduction performance but has the best economic performance with an LCC value of − 46.38 USD. The scenario with the shortest payback time is straw-to-ethanol, which take only 2 years. Sensitivity analysis reveals that the product has the most significant impact on the environmental and economic performance. The study analyzed the environmental impacts and economic benefits of these straw utilization pathways to provide solutions for sustainable straw management. [ABSTRACT FROM AUTHOR]

The surge of medical waste (MW) generated during the COVID-19 pandemic has exceeded the disposal capacity of existing facilities. The timely, safe, and efficient emergency disposal of MW is critical to prevent the epidemic spread. Therefore, this review presents the current status of MW generation and disposal in China and analyzes the characteristics and applicability of emergency disposal technologies. The results show that movable disposal facilities can dispose of infectious MW on site, even though most of their disposal capacity is at a low level (<5 t/day). Co-disposal facilities need to be reformed completely for emergency MW disposal, in which separate feeding systems should be taken seriously. Specifically, municipal solid waste (MSW) incineration facilities have great potential to improve emergency MW disposal capacities. For hazardous waste incineration facilities, compatibility of the wastes must be matched to the composition and calorific value of the waste. As for cement kiln, MW can only be used as an alternative fuel instead of a raw material for cement. Based on the environmental risk and technical adaptability, the six emergency MW disposal technologies are recommended to be prioritized as follows: movable microwave sterilization, movable steam sterilization, movable incineration, co-incineration with hazardous waste, co-incineration with MSW and co-disposal in cement kilns. Infectious MW, especially COVID-19 MW, should be prioritized for disposal by centralized and movable disposal facilities, while non-infectious MW can be disposed of using co-disposal facilities. All stakeholders should strengthen the delicacy management of the end-of-life stage of MW, including collection, classification, packaging identification, transportation, and disposal. Currently, it is necessary for centralized disposal enterprises to follow the emergency disposal operation flowchart. From a long-term strategic perspective, making full use of regional movable and co-disposal facilities in the megacities can effectively enhance the emergency MW disposal capacity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)