Waste Treatment Options Research Articles

Energy recovery and waste treatment using the co-pyrolysis of biomass waste and polymer.

The pyrolysis of spent coffee grounds (SCG) and polymers was examined as a waste treatment option for energy recovery and carbon sequestration. Rice straw-derived biochar was used as control biochar to evaluate the sorption capacity and energy production capability of SCG-derived biochar. SCG are characterised by high levels of volatile matter, rendering them suitable as an energy source. SCG were converted to biochar, bio-oil, and syngas via pyrolysis, with yields of 22%, 33%, and 45%, respectively. The high heating value (HHV) of the biochar and bio-oil was 20.6 and 22.9 MJ kg-1, respectively, indicating that they could be used as supplementary fuels. Co-pyrolysis with polymers (20 v v%-1) increased the HHV of biochar. Accordingly, the maximum production of CH4 and H2 increased from 0.3 and 0.04 mmol g-1 to 3.4-6.3 and 0.8-1.3 mmol g-1, respectively. Polystyrene most strongly enhanced the yields of CH4 and H2, followed by polypropylene and polyethylene; this order was likely to be in accordance with the number of carbon and hydrogen atoms present in the monomers. Similar to rice straw-derived biochar, the biochar produced from SCG demonstrated a high sorption capacity for 2,4-dinitrotoluene and chromate due to its high carbon content and anion exchange capacity, respectively. Laboratory pot tests revealed that the coffee grounds-derived biochar was able to increase the growth of young radish. Our results suggest that the pyrolysis of SCG and polymer may be a promising option for waste treatment, energy production, and carbon sequestration.

Energy recovery from food waste and garden and park waste: Anaerobic co-digestion versus hydrothermal treatment and anaerobic co-digestion

The feasibilities of the anaerobic co-digestion of two of the most relevant biowastes, food waste and garden and park waste, were evaluated and compared with the hydrothermal treatment of each waste and the anaerobic co-digestion of raw biowastes with the process water generated. The effects on the process stability and energy recovery were also analyzed. Anaerobic digestion was the best option for food waste treatment from an energetic point of view, with 81% recovery of the energy stored in the feedstock, while the highest energy recovery from garden and park waste was obtained for the solid fraction generated from hydrothermal treatment (85.5%). In addition, the anaerobic co-digestion of food waste with 5% of the process water generated from garden and park waste showed a similar energy recovery to that of food waste only (∼80%), thus improving the biological stability of the process.

Biomedical waste management in Panchakarma practice: Present scenario and scope

Ayurveda is a traditional medical system of India. In Ayurveda, Panchakarma (fivefold detoxification treatment) procedures are designed for internal purification and cleansing. As per the Indian government’s initiative (launched in September 2014), Ayurveda is part of wellness industry. There is a constant rise in the number of Ayurveda clinics, hospitals, wellness centers, and spas in India. The various Panchakarma procedures performed in these hospitals, clinics, wellness centers, and spas generate biomedical wastes (BMW). Metropolitan areas in India bring about 62 million tonnes of wastes annually, and this figure is predicted to rise to 165 million tonnes by 2030. Forty-three million tonnes of the municipal solid waste are collected every year, of which 31 million are disposed of in landfills and only 11.9 million are treated. Pharmaceutical wastes are one among them. Reports from the Indian medicinal plant industries indicate that presently more than 9000 plant industries are registered in India, which produces a huge amount of waste each year. This has created a need in the proper management of waste generated. Here is the description and discussion of categorization, classification, and treatment options for waste generated during Panchakarma procedures in Ayurveda hospitals. Effective and proper management of the BMW is necessary to maintain personal as well as environmental health. The current available techniques for the treatment of waste generated during Panchakarma procedure are sewage drainage, incineration, and landfill. Nothing turns around to be waste until it is being not used further with intelligence. The natural cycles of life taught us the same through science: utilizing of three Rs of ideal waste management. While further advancement can include the use of phytoremediation, composting, vermicomposting, biofiltration, bioaugmentation and use of solar energy in waste management.

Food waste treatment option selection through spherical fuzzy AHP

In line with the increase in consciousness on sustainability in today’s global world, great emphasis has been attached to food waste management. Food waste is a complex issue to manage due to uncertainties on quality, quantity, location, and time of wastes, and it involves different decisions at many stages from seed to post-consumption. These ambiguities re-quire that some decisions should be handled in a linguistic and ambiguous environment. That forces researchers to benefit from fuzzy sets mostly utilized to deal with subjectivity that causes uncertainty. In this study, as a novel approach, the spherical fuzzy analytic hierarchy process (SFAHP) was used to select the best food treatment option. In the model, four main criteria (infrastructural, governmental, economic, and environmental) and their thirteen sub-criteria are considered. A real case is conducted to show how the proposed model can be used to assess four food waste treatment options (composting, anaerobic digestion, landfilling, and incineration). Also, a sensitivity analysis is generated to check whether the evaluations on the main criteria can change the results or not. The proposed model aims to create a subsidiary tool for decision makers in relevant companies and institutions.

Analytical Approach for Prioritizing Waste Management Practices

The socio-environmental hazards of poor waste management practices in health care sector have been explored in the recent years. It has also been observed that through effective waste management practices, health care units(HCU) not only could reduce their contribution to social and ecological hazards but also can save significant amount of money. Hence, a lot of researchers and practitioners are focusing on developing innovative techniques and policies that will help HCUs operate in a socio-environmental responsible manner. In this regard this research has attempted to explore the waste treatment options available in Papua New Guinean health care sector and identify the best alternative for them. This research employed primary data collection through questionnaire survey, secondary data collection through review of published reports and research papers and analysis of the responses of respondents through Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS). The results revealed that open burning practices of HCWM has been judged as the worst alternative.

Assessment and projection of environmental impacts of food waste treatment in China from life cycle perspectives

China produces vast amounts of food waste every year. However, the environmental impact of the current treatment of food waste and its potential for improvement are not very clear. Therefore, this study applied life cycle assessment to compare the current major treatment options for food waste and to systematically quantify the environmental impact of current and future food waste treatment in China based on the amount and treatment mode of food waste. In 2020, 125 million tons (Mt) of food waste was generated in China. Its treatment consumed 30.1 Mt oil-Eq of fossil fuels and 16.7 Mt of freshwater, and released 37.5 Mt of CO2-Eq. A promising finding was that if the proportion of food waste treated by anaerobic digestion exceeded 40% and landfilling was terminated by 2050, most impact categories would be reduced by more than 50%. Although anaerobic digestion is a potentially more environmentally friendly treatment option due to more output of energy and resources, it is worth noting that it consumed more freshwater than incineration and landfilling. Electricity consumption contributed more than 50% of the environmental burden of anaerobic digestion. Therefore, for the upstream of anaerobic digestion, China should further implement policies of waste classification and promote zero-waste cities, so that less impurities and more food waste would enter anaerobic digestion instead of landfills. Whereas downstream, the resource utilization of biogas and digestate enhance should be enhanced so as to strengthen the environmental sustainability of anaerobic digestion.

Structural and radiological characterization of irradiated RBMK-1500 reactor graphite

This study aims to characterize the irradiated RBMK-1500 nuclear graphite in terms of both structural and radiological properties. The experimental results of morphological and structural analysis of the irradiated graphite samples by using SEM, Raman spectroscopy as well as the theoretical evaluation of primary displacement damage are presented. Moreover, the experimental and theoretical evaluation of the neutron flux is provided and the presence of several γ emitters in the analyzed graphite samples is assessed. Furthermore, the improved version of rapid analysis method for 14C activity determination is applied and the experimentally obtained results are compared with calculated ones. Results indicate that structural changes are uniform enough in all the analyzed samples. However, the distribution of radionuclides is non-homogeneous in the irradiated RBMK-1500 reactor graphite matrix. The comprehensive understanding of both structural and radiological characteristics of nuclear graphite is very important when dealing with decision about irradiated graphite waste management strategy or treatment options prior to its final disposal.

Multi-criteria analysis of municipal solid waste treatment technologies to support decision-making in Kisumu, Kenya

The directive to close the dumpsite in Kisumu, Kenya has made the search for alternative solid waste treatment and disposal technologies urgent. The aim of this research is to support the decision-making process by analyzing multiple socioeconomic and environmental parameters of salient solid waste treatment options. We used multi-criteria analysis to assess and compare anaerobic digestion, sanitary landfill, bioreactor landfill, and incineration. Informed by field observations and interviews, the chosen assessment criteria were economic costs, electricity generation, GHG emissions, land footprint, air pollution, soil and water contamination, and compatibility with recycling efforts. A literature review yielded quantitative and qualitative data that supported the analysis and the ranking of solutions according to performance in each criterion. Our analysis shows that anaerobic digestion is a suitable solution for Kisumu, due to its reduced environmental impacts, production of electricity and fertilizer, suitability to treat the large organic waste stream generated in the city, and compatibility with independent recycling activities. Landfilling represents a cheap solution; however, previous failed initiatives indicate that finding available land close to main waste generators is a challenge. Incineration is costly and requires advanced air quality control equipment and high combustibility of incoming waste, which is not the case for Kisumu, where over 60% of waste stream is organic/wet. Our results and recommendations are targeted for the Kisumu case, but they can be relevant for researchers and policymakers elsewhere, especially in low- and middle-income cities facing similar challenges.

Study on the effect of municipal solid landfills on groundwater by combining the models of variable leakage rate, leachate concentration, and contaminant solute transport

The landfill with low economic cost and technical barrier has become a popular option for municipal solid waste treatment, but it is likely to seriously pollute groundwater by solute leaching. In this study, the pollutants concentration model, leakage rate model, and the solute transport model were coupled to investigate the effect of municipal solid waste landfill on groundwater quality. Major results obtained are, (1) the leakage rate of leachate differs significantly among the landfilling stage, covering stage and completely covered stage as the leachate depth varies with the infiltration rainfall. The contact condition between HDPE and CCL was found to be a key factor in determining the leakage rate of leachate. Ensuring good connection between HPDE and CCL is thus critical in protecting groundwater from being polluted by landfill. (2) The NH3–N as a proxy for organic pollutants was generated via the degradation process, and Cl− as a proxy for inorganic pollutants is a leachable fraction of mobilized substances. The concentration of Cl− is higher than that of NH3–N before 7600 days, then the concentration of NH3–N becomes roughly stable while that of Cl− continues to decrease. (3) The load of NH3–N as a proxy for organic pollutants declines linearly downwards before the completely covering stage. The load of Cl− as a proxy for inorganic pollutants increased during the first five years, and then declined. (4) In the case study, the path of maximum pollutants concentration is perpendicular to the groundwater contour, and the maximum pollutants concentration has two peaks, occurring on 7106 days and 11,554 days, respectively. The change laws of maximum pollutants concentration are similar for different connections between HPDE and CCL.

Waste-to-energy: Coal-like refuse derived fuel from hazardous waste and biomass mixture

This study aimed to develop Refuse Derived Fuel (RDF) with high Calorific Value (CV) from mixed hazardous wastes and biomass. The potential utilization of newly developed RDF in cement production as a fuel substitute for coal has been investigated. In this work, five types of mixed hazardous industrial wastes (rubber waste, mixed waste, paint sludge, palm oil sludge and wastewater treatment plant sludge) and three biomass types (sawdust, paddy husk and empty fruit bunch) have been used. The newly developed RDF developed in this study has a CV of approximately 18,652 kJ/kg, and its volatile matter, fixed carbon and ash content of 32 %, 40 % and 28 %, respectively. The study is revealed that substituting 5 ton/hour of RDF in the coal only emits about 301 mg/m3 of NOx, which is within the regulatory limits in Malaysia. Besides, the emission of heavy metals, including Zinc, Arsenic, Lead, Copper, Antimony, and Chromium, was also within the regulatory limits. RDF in cement manufacturing kilns is economically and environmentally attractive, as the combustion of RDF allows for a reduction of about 2.25 kg of CO2 per kg compared to coal. In terms of the efficiency of clinker and stack gas emission values, the substitution of 15 % of RDF to the coal at a feeding rate of 5 ton per hour in cement production did not cause any processing and quality issues in the existing cement production process. The result revealed that substituting 15 % of RDF with the coal in 5000 ton/day cement plant may reduce 112.8 USD/hour in operating cost. Additionally, 140 USD/hour of net saving could be achieved by saving 2.52 ton/hour of CO2 emitted from the cement production. Overall, the results concluded that RDF is a very promising resource recovery and waste treatment option for hazardous waste management.

Carbon footprint reduction potential of waste management strategies in tourism

Tourism is one of the major economic factors contributing to growth and jobs worldwide. The number of international travellers has increased more than 50-fold in the past 70 years. However, the contribution of tourism to (municipal) waste generation is also large and is increasing, accompanied by an increase in some environmental and socio-economic impacts. An average value of 1.67 kg waste is now generated per tourist (Obersteiner et al., 2017). Waste prevention and recycling should therefore be major objectives in tourist waste management by municipal authorities.Within the EU H2020-funded project “URBANWASTE – Urban Strategies for Waste Management in Tourist Cities”, eco-innovative waste prevention and management strategies were implemented in 10 pilot cities with high levels of tourism, in order to reduce urban waste production and improve municipal waste management. This study examined the potential greenhouse gas (GHG) emissions savings for three selected waste prevention and treatment options: food waste prevention, reductions in single use plastic and increased separate collection and recycling of waste. Benefits were expressed per kg waste prevented or diverted higher up the waste hierarchy and per 1000 tourists.The measures achieved potential GHG emission savings of between 4 and 189 kg CO2-eq. per 1000 tourists, depending on local conditions such as the existing waste management system. Measures tackling food waste reduction and separate collection had low emissions associated with the measure itself, whereas for assessed measures reducing the use of single use plastics by providing reusable alternatives, emissions associated with the measures were relatively high. This was due to the emissions associated with the production of the alternative reusable products. Influencing factors reducing the carbon footprint of waste management in tourism other than the kind of waste focused on were the existing waste management system (especially for biowaste) as well as the practicability and scalability of measures under the divers regional circumstances.

The particle size-dependent distribution of chemical elements in mixed commercial waste and implications for enhancing SRF quality

Mixed commercial waste (MCW) contains contaminants that are important for several waste treatment options, e.g. the production and utilization of SRF for which limit values exist. Because these contaminants can be linked to specific materials but also occur in certain particle size classes, this paper presents the particle size-dependent distribution of 30 elements (Ag, Al, As, Ba, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Pd, Sb, Si, Sn, Sr, Ti, V, W, Zn) in nine particle size classes (<5 mm, 5–10 mm, 10–20 mm, 20–40 mm, 40–60 mm, 60–80 mm, 80–100 mm, 100–200 mm and 200–400 mm) of coarsely shredded mixed commercial waste collected in the area of Graz, Austria. For 27 elements a negative correlation between concentration and particle size was observed, i.e., increasing concentrations with decreasing particle size. The fine fraction <5 mm contained the highest concentrations and the most considerable total amount of most analytes (e.g., > 40% of Hg, Mn, Mo, Sn, W). The removal of this fraction therefore theoretically reduces concentrations [mg/kgDM] of the 27 negatively-correlated elements in the screen overflow by 2.1 to 38%, while Cd (+10%), Sb (+12%), and Cl concentrations (+17%) and the lower heating value (+16%) increase. Besides containing contaminants, the fine fraction <5 mm consisted of ~11% Fe, 12% Ca, 12% Si, and 1.5% Al, all of which are valuable raw materials for the cement industry. Fe was found to be present as oxides, primarily as magnetite and wuestite. Calcium was present as carbonates (calcite, dolomite), but also considerable amounts of calcium sulfates (bassanite, gypsum, anhydrite). Concludingly, while screening can significantly improve SRF quality with respect to heavy metals, valuable raw materials for the cement industry may be removed as well, potentially resulting in a conflict between environmental protection and resource utilization.

Environmental and economic sustainability in public contexts: the impact of hand-drying options on waste management, carbon emissions and operating costs

Due to the high density of users hosted everyday, public buildings are important producers of waste and emissions of greenhouse gases (GHGs). Public restrooms play an underrated role in waste generation and GHG emissions, especially if paper towels are used as the hand-drying method. The choice of the hand-drying method (i.e., paper towels vs. electrical hand dryers) also affects the economic balance of a public institution, involving costs for the purchase of hand-drying materials/apparatuses, energy and waste disposal. The present paper aims at evaluating the economic and environmental impact of the introduction of electrical hand dryers (alternative scenario) in place of paper towels (reference scenario) in a public building. The paper presents a solid methodology, based on a numerical experiment approach, to identify a decision criterion for establishing the economical convenience of adopting the alternative scenario in public restrooms. Key factors affecting the choice between the proposed alternatives are presented and discussed in a dedicated sensitivity analysis. From the environmental point of view, this study evaluates the impact of each scenario in terms of GHG emissions, related to multiple waste treatment options and different electric grid mixes. Based on the experimental assumptions, the method allowed concluding that the alternative scenario becomes economically convenient when the number of daily usages (N) is > 57 ± 4. The environmental convenience of the alternative scenario is visible even at N < 10. The method here described can be successfully used to support strategic decisions for cost optimization and environmental mitigation in institutional buildings.

Integrating life cycle assessment for design and optimization of methanol production from combining methane dry reforming and partial oxidation

CO2 capture and utilization (CCU) is a potential solution for combating global warming potential. Utilization of CO2 as a renewable raw material for producing methanol has been intensively investigated. Nevertheless, the benefits of CO2 utilization cannot be guaranteed unless the entire production process is rigorously evaluated and optimized. This study attempts to minimize CO2 emissions of the methanol production process via the synthesis of intermediate syngas using the dry methane reforming (DR) method in combination with the partial oxidation (PO) of methane. We noted that the contributions from DR and PO to the overall reaction process depended on the input raw material ratios. Marked differences in desired operating conditions were noted when maximizing syngas and methanol yields, thereby making process optimization difficult. Herein, to find the optimal operating conditions for minimizing overall CO2 emissions, effective process design and simulation, and the cradle-to-gate life cycle assessment (LCA) were integrated. Process CO2 emissions, including those from all sources of indirect and direct CO2 emissions from raw materials, utility production processes, and “end-of-pipe” waste treatment option were evaluated based on noted variations in the identified key variables. Suitable operating conditions for reducing the total process CO2 emissions were proposed. Although the current study results in low level of CO2 utilization, it attains a low CO2 emissions process for producing methanol via syngas (i.e., 0.81 kg CO2/kg methanol). The results obtained herein highlight the significance of implementing LCA method using suitable evaluation boundary to design environmentally friendly CO2 utilization processes.

Thermo-chemical conversion of carbonaceous wastes for CNT and hydrogen production: a review

Thermo-chemical conversion of carbonaceous wastes such as tyres, plastics, biomass and crude glycerol is a promising technology compared to traditional waste treatment options (e.g. incineration and landfill).

LB starts MoReTec pilot unit.

Mixed commercial waste (MCW) contains contaminants that are important for several waste treatment options, e.g. the production and utilization of SRF for which limit values exist. Because these contaminants can be linked to specific materials but also occur in certain particle size classes, this paper presents the particle size-dependent distribution of 30 elements (Ag, Al, As, Ba, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Pd, Sb, Si, Sn, Sr, Ti, V, W, Zn) in nine particle size classes (<5 mm, 5–10 mm, 10–20 mm, 20–40 mm, 40–60 mm, 60–80 mm, 80–100 mm, 100–200 mm and 200–400 mm) of coarsely shredded mixed commercial waste collected in the area of Graz, Austria. For 27 elements a negative correlation between concentration and particle size was observed, i.e., increasing concentrations with decreasing particle size. The fine fraction <5 mm contained the highest concentrations and the most considerable total amount of most analytes (e.g., > 40% of Hg, Mn, Mo, Sn, W). The removal of this fraction therefore theoretically reduces concentrations [mg/kgDM] of the 27 negatively-correlated elements in the screen overflow by 2.1 to 38%, while Cd (+10%), Sb (+12%), and Cl concentrations (+17%) and the lower heating value (+16%) increase. Besides containing contaminants, the fine fraction <5 mm consisted of ~11% Fe, 12% Ca, 12% Si, and 1.5% Al, all of which are valuable raw materials for the cement industry. Fe was found to be present as oxides, primarily as magnetite and wuestite. Calcium was present as carbonates (calcite, dolomite), but also considerable amounts of calcium sulfates (bassanite, gypsum, anhydrite). Concludingly, while screening can significantly improve SRF quality with respect to heavy metals, valuable raw materials for the cement industry may be removed as well, potentially resulting in a conflict between environmental protection and resource utilization.

Life cycle assessment of volatile fatty acids production from protein- and carbohydrate-rich organic wastes

Volatile fatty acids (VFAs) are platform molecules with numerous applications. They can be obtained by adjusting the operational conditions of anaerobic digestion to avoid methanogenesis while focusing on fermentative stages. There are gaps in the knowledge of how, from a life-cycle perspective, the fermentative process performs in VFAs production from waste, including environmental consequences of substituting common commodities in the current market. Mass and energy balances of VFAs production from protein-rich microalgal and carbohydrate-rich agro-industrial wastes were used herein as a key source of inventory data for life cycle assessment. Two waste treatment options were considered: (i) VFAs production (anaerobic fermentation) plus anaerobic digestion of the resulting waste after VFAs separation, and (ii) anaerobic digestion of the original waste for bioenergy. Several scenarios were formulated to evaluate their life-cycle performance. VFAs production generally shows a better environmental behaviour than conventional anaerobic digestion, principally due to the substitution of conventional chemicals.

Potential of Producing Compost from Source-Separated Municipal Organic Waste (A Case Study in Shiraz, Iran)

Developing countries face serious environmental, social and economic challenges in managing different types of organic waste. Proper treatment strategies should be adopted by solid waste management systems in order to address these concerns. Among all of the treatment options for organic waste, composting is the most approved method as an effective strategy to divert solid waste from landfills. This experimental research aimed to examine the potential of producing compost from source-separated municipal organic waste in Shiraz, Iran. Market waste (fruits and vegetables) and garden waste (plant residues) were used as the raw input materials. They were subjected to the windrow pile composting method in an open site area. The process was monitored against several physical, chemical and biological parameters. In-situ measurements (temperature and moisture content) were carried out on a daily basis. Sampling and lab analyses were conducted over the period of the biological treatment. The final product was of acceptable moisture and nutrient levels, pH, Electrical Conductivity (EC), and Carbon/Nitrogen ratio. All of the analyzed compost samples had lower concentrations of heavy metals than the Iranian and German standards. Overall, the results obtained revealed that composting is a promising method for municipal organic waste treatment. The findings also imply the effectiveness of the source-separation collection method in the production of high-quality compost.

A Comparative Study Between Municipal Solid Wastes Management Options in Processing Stage of Al-Diwaniyah city / Iraq

The plan of this study is determining the best option for solid waste treatment in the Diwaniyah city – Iraq. where the comparison between two common options in solid waste treatments, the first option is the incineration process with energy recovery for all waste components and the second option is “reusing inorganic and recycling organic compost” (RIROC). In this study, we depended numbers of criteria that included the environmental impact, the cost Investment, operation and maintenance costs, financial benefits, work experience, stabilization, quantities of by-product waste, and city needs. Due to the nature of wastes which contain high organic component and also high moisture content which decreases the low heating value of MSW where it is (6000 - 7000) KJ / Kg. According to these parameters and the wastes properties, the second option (RIROC) was the suitable choice due to the investment cost is less than the incineration option and the net profits are similar approximately where the net profits of the incineration and (RIROC) are 11888 $/day and 11597$/day respectively.

EXTENDED TRIPLE BOTTOM LINE BASED EVALUATION OF REVERSE LOGISTICS OPTIONS FOR CONSTRUCTION WASTE MATERIAL

The construction sector not only plays a significant role in the economic development of a country but also generates considerable construction waste. Treatment of such waste is essential to avoid loss of potentially recoverable material, minimize environmental pollution, reduce monetary losses, and other related hazards. Reverse logistics concept gains popularity due to its material recovery aspect, therefore considered a waste treatment option. However, the selection of the most appropriate treatment strategy requires a critical analysis of various factors. In the past, firstly, technical and economic factors were considered mainly before selecting a treatment method, with limited to no consideration given to environmental, social, and political factors, especially in low and middle-income countries. Secondly, the selection of such treatment methods was mostly based on qualitative assessments. To overcome these issues, at first, this study extends the concept of Triple Bottom Line (TBL) by adding two more lines of technical and political aspects and called it as extended TBL (ETBL). Secondly, a quantitative ETBL scoring method is proposed based on a probability-impact approach to help decision-makers select an appropriate reverse logistics option for construction waste material. A list of bottom-line factors was extracted from the comparison of existing practices among different countries. Lastly, suggestions to Hong Kong stakeholders were provided as per ETBL assessment, which will help future decision-making.