Waste Mitigation Research Articles

High rate CO2 valorization to organics via CO mediated silica nanoparticle enhanced fermentation

Carbon dioxide (CO2) valorization to high energy density fuels presents an economically sound approach to directly couple waste mitigation with sustainable energy production, yielding tremendous environmental and societal benefits. Here, a new two-stage hybrid system was developed that pairs highly efficient electrochemical CO2 reduction (CO2-R) to carbon monoxide (CO) with acetogenic bacteria for the rapid production of green chemicals. This original design seeks to solve issues in mediator production and utilization evident in related studies. A progressive silver-based gas diffusion electrode with anion exchange membrane sustained current densities of 200 mA/cm2 for over 240 h at a time and produced CO at excellent Faradaic efficiencies of over 80% at a cell voltage ca. 3.2 V. The effluent gas from the CO2 electrolyzer was connected to a bioreactor containing Clostridium ljungdahlii where the blend of CO/CO2 was converted into a mixture of mainly acetate and ethanol. This demonstrates the first time this organism has been tested in a two-stage hybrid CO2-R system. Competitive acetate and ethanol production rates of 17.87 ± 7.1 and 3.23 ± 1.4 mg/L/h were achieved under autotrophic conditions. In addition, mercapto-modified silica nanoparticles were developed to increase gas mass transfer and resulted in 217% and 224% increases in acetate and ethanol production rates, respectively. This system presents a viable approach to produce sustainable fuels and chemicals in a process that exploits commercially scalable C1 electron carries.

What influences consumer food waste behavior in restaurants? An application of the extended theory of planned behavior

Consumer food waste during the consumption stage is usually generated in different settings (at home or out-of-home). Consumer food waste behavior has been the focus of substantial investigation in the search for the mitigation of food waste in households. However, researchers have not treated consumer food waste behavior in restaurants in much detail. This study aims to test an extended Theory of Planned Behavior by including price consciousness and food taste to understand the antecedents of food waste behavior in restaurants. An online survey provided quantitative data from 329 participants. The results showed that (1) the extended TPB model is useful in predicting consumer food waste behavior in restaurants with an improved variance in food waste behavior from 13% to 15%; (2) intention to reduce food waste and perceived behavioral control had a significant negative effect on food waste behavior; (3) food taste exerted a significant positive effect on food waste behavior; (4) attitudes towards food waste, perceived behavioral control and price consciousness positively affected intention to reduce food waste. The current study represents a further step towards understanding consumer food waste behavior in restaurants.

Energy and life cycle impact assessment for xylitol production from corncob

The conversion of biobased feedstocks into energy and value-added chemicals is one main approach to address the current global challenge for waste mitigation through the biorefinery mode. Corncob biomass which is one of the most abundant agricultural residue in India with a high hemicellulose content, can serve as a potential low-cost raw material for food-grade xylitol production. The present study demonstrates a process for xylitol production from corncob biomass with detailed energy and life cycle analysis for viability assessment. The major highlight of the process is the use of microbial fermentation, where biomass-derived D-xylose is converted to xylitol with high selectivity. Overall, 0.502 kg of xylitol crystals could be produced from 3.5 kg of corncob biomass. Simulation analysis revealed that the evaporators are the primary consumers of energy, and the process of heat integration can significantly reduce the energy requirements of the overall process. Environmental impacts of the system evaluated showed emission results of 8.68 kg CO2 equivalent and revealed that marine aquatic and freshwater eco-toxicity are the only possible contributors to the environment. The results suggest that the process would have favourable energy balances, which can be used in pilot plant and heat exchanger network design and operation for xylitol production scale up to 500 L.

The surfactant addition mode on the collision and attachment of bubbles on hydrophilic quartz and hydrophobic methylated quartz

In order to improve the utilization efficiency of surfactants, a novel addition mode injects surfactant vapor into the bubbles has been proposed. The effect of the cationic surfactant dodecylamine (DDA) and the frothers methyl isobutyl carbinol (MIBC) and 2-octanol on the collision between bubbles and hydrophilic/hydrophobic quartz was evaluated under three surfactant addition modes namely as: 1) vapor in air, 2) dissolved in water, and 3) vapor in the air and dissolved in water. When the surfactants were added as vapor in the air the induction time and collision frequency were smaller than those when surfactants were dissolved in water and added partially dissolved in water and as vapor in air. This is independently of the surfactant sort and quartz surface property. Of these three surfactants, when added as vapor, DDA showed smaller collision frequency and induction time as compared to MIBC and 2-octanol. When the surfactants were dissolved in water and added partially dissolved in water and as vapor mixed with the air, the induction time and collision frequency were larger with DDA as compared to MIBC and 2-octanol. The induction time increased nearly linearly with the collision frequency, independently of the surfactant sort, surface property and surfactant addition mode. The contact angle decreased as the induction time increased on the hydrophobic methylated quartz surface while it was almost constant as the induction time increased on the hydrophilic quartz surface. The results may provide valuable insight into the development of surfactant utilization and waste mitigation in flotation.

Unique Aspects of Thermal Plasma Torches and Reactor Design for Process Applications

Novel features of arc plasma devices with thermionic and thermo-chemical cathodes and development of associated thermal plasma process reactors are investigated from device design and application point of view. Different types of plasma torches and open arcs, their fundamental differences in architecture, jet behavior, operational constraints, and evolution of interesting electromagnetic forces inside them have been probed. Investigation of instabilities in arcs through direct real-time imaging of arc path using fast photography and impact of powder loading on such instabilities are presented. Development of low power air plasma torches delivering large volume high-temperature plasma jet with long penetration depth has been investigated together with an estimation of hazardous NOx, produced from such devices during operation. Interesting attributes of various types of thermal plasma reactors including plasma spray chemical vapor deposition (CVD) reactors for thick and dense coating, reactors for generation of H-OH plasma, radio frequency (RF) thermal plasma reactors for the synthesis of nanostructures, and air plasma gasifier reactors for environment-friendly mitigation of municipal solid waste (MSW) and electronic wastes have been presented. Coke bed air plasma gasifiers are specially investigated for their important technological aspects. Experimental results are presented with simulation supports for enhanced understanding, wherever necessary.

Liquefaction resistance of sand amended with biochar

Biochar is a solid carbon material produced by heating organic biomass in the absence of oxygen through a process known as pyrolysis. Scientists and policy makers have recognised its potential role in carbon sequestration, reducing greenhouse gas emissions, renewable energy, waste mitigation and as soil amendment. To date, most studies related to biochar application to soil have focused mainly on the agronomic benefits, while little attention is paid on its effects on soil properties from geotechnical point of view. Considering that biochar can be produced from biomass, its use would fit satisfactorily the current trends of recycling wastes for ground improvement and liquefaction mitigation. To address this, the effect of adding various proportions by weight of biochar, derived from poultry litter, on the liquefaction resistance of sand is investigated through undrained cyclic triaxial tests. The findings suggest that, contrary to other earlier published reports using another type of biochar, adding poultry litter biochar to sand decreases its liquefaction resistance in a similar manner as adding non-plastic fines. The results highlight the fact that the type of biochar used as soil amendment is important in determining whether the liquefaction resistance of the host sand will improve or not.

An international survey on the use of low titer group O whole blood for the resuscitation of civilian trauma patients in 2020.

An international survey on the use of low titer group O whole blood for the resuscitation of civilian trauma patients in 2020.

Exploring managerial approaches to mitigating solid waste in hotels of Lagos, Nigeria

Due to a steady growth of tourism, hotels in Nigeria generate disproportionate amounts of solid waste. Little is however known about what approaches, if any, Nigerian hoteliers adopt for its mitigation. This study has set to establish the approaches to managing solid waste and evaluate their effectiveness in a sample of hotels in Lagos. To this end, it has applied the method of in-depth, semi-structured interviews with 17 hoteliers to reveal the role of organisational (managerial and staff attitudes, corporate policies), institutional (governmental policies) and consumption market related (consumer attitudes) factors in shaping the scope of solid waste mitigation. The interview results have demonstrated that Lagos hotels do very little to mitigate solid waste generation. This was attributed to the insufficient support received from the government, but also to the disinterest of hotel guests, managers and employees in environmental conservation. To improve the quality of solid waste management in Nigerian hotels, it is necessary to raise environmental commitment of managers and improve environmental awareness of guests and staff. Governmental involvement is required in the form of educating hotel guests and providing environmental training and ‘green’ incentives to hoteliers.

What Are the Conflicting Tensions in an Italian Cooperative and How Do Members Manage Them? Business Goals’, Integrated Management, and Reduction of Waste within a Fruit and Vegetables Supply Chain

Social enterprise is a model of hybrid organization driven by the need to generate positive externalities by reinvesting their surplus for social and environmental objectives. One of the biggest problems arising from joining financial goals with social goals is the presence of increasing tensions between the members and stakeholders involved. Nevertheless, there has not been enough focus on how managers, employees, and stakeholders respond to the tensions caused by contradictions and how they try to reach a balance between financial, environmental, and social goals. Therefore, the present study is aimed at investigating how members of an agricultural cooperative in the Apulia region (Italy) try to join the organizational forms of business and social values, namely, the sustainable practices related to CO2 emission reduction, resource use efficiency, and food waste mitigation. Additionally, the study goes further and explores whether and how these contradictory pressures are solved. Starting from the sensemaking approach, the study carried out an inductive case study through the use of a multiple case study design and in-depth interviews. The findings highlight the following two novel aspects: (1) Managers prefer to adopt a cumulative mitigating hybridization approach and (2) a weak integration can be noticed between social and commercial dimensions, originating from a lack of holistic perspective and poor interorganizational communication.

Lean Construction: Evaluation Of Waste And Carbon Footprint In Construction Project

Construction projects are large-scale works that are mostly done in open areas. This large and open activity has the potential to produce waste and carbon footprint. Therefore, the purpose of the research is to find out the causes, impact analysis, and possible mitigation of waste and carbon footprint in the construction project. Survey and in-depth interviews with construction projects become research methods. The results showed that the causes of waste were dominated by worker factors while the main causes of waste in the design phase are client requests, DED changes and complexity, and design errors. Meanwhile, carbon footprint occurs because it does not use renewable energy and environmentally friendly materials. The impact of indirect waste is 8.93% of the total workers’ budget, while direct waste is 5.64% of the material budget, which is at the contractor’s tolerance threshold of 3-6%. The carbon footprint in the production phase still dominates the contribution to the amount of carbon footprint produced when compared to the transportation, fabrication and installation phases.

A comparative study of food waste management in full service restaurants of the United Kingdom and the Netherlands

The EU-28’s food service sector generates excessive amounts of food waste. This notwithstanding, no comparative, cross-national research has ever been undertaken to understand how food waste is managed in restaurants across the EU-28. This study contributes to knowledge by presenting a first attempt to conduct a comparative analysis of restaurant food waste management practices in the UK and the Netherlands. It finds that although restaurateurs in both countries use demand forecasting as a prime approach to prevent food waste, forecasting does not always work. When this happens, food waste management programmes such as repurposing excess foodstuffs, redistribution of surplus food and consumer choice architecture are mostly considered commercially unviable. To improve the effectiveness of food waste management in the food service sectors of the UK and the Netherlands it is necessary to ensure that food waste mitigation becomes a corporate target for restaurateurs and the progress towards its achievement is regularly monitored by top management. This corporate commitment should be facilitated by national policy-makers, but also by EU regulators, by raising consumer awareness of food waste, incentivising surplus food redistribution and enabling food waste recycling.

Ecological Footprint Accounting of Non- Biodegradable Wastes of Angeles City, Philippines: The Anthropogenic Shift to Biodegradables

This study factored the Ecological Footprint Accounting on the Municipal Solid Wastes of Angeles City, Philippines using the Waste Analysis and Characterization Summary for 2015, with projections subdivided into the solid wastes of Angeleǹos, expressed as waste generation per capita, depict the level of waste consumption, quality of urban habitat, and the acceleration on waste disposal based on the population growth rate and diversion rate. The results were quantitatively analyzed using Ecological Footprint Accounting and interpreted in monetary terms through Benefit-Cost Analysis. The major research processes include: Analysis of waste generation per capita; Waste Projections net of targeted diversion on non-biodegradables; Cost Analysis on diverted wastes; and Income Analysis on Recyclables. The waste generation for the next five years will be generated 90% by households; 10% by educational and other institutions. With waste composition of 37% biodegradable, 20% recyclables and 43% non-biodegradable. By the year 2022, the city is expected to generate 159 kg yr-1∙106 with waste mitigation at a decreasing rate of 96.89% despite the population acceleration at 136% or equivalent to 561,000 constituents. Lastly, the five-year Benefit-Cost Analysis yielded a budgetary savings of PhP395M, equivalent to US$ 7.4M or an average municipal annual cost savings of 39%

Diagnóstico do Lixo Marinho e Ações de Educação Ambiental na Praia de Navegantes/SC

O lixo marinho tem contribuído consideravelmente para a poluição marinha e é uma das tendências globais para a questão ambiental. Como resultado da poluição marinha tem-se os impactos à biota, impactos econômicos à pesca e os impactos visuais nas praias. É necessária a realização de estudos que identifiquem a composição, abundância e o comportamento desses detritos diante das variáveis meteorológicas afim de contribuir para que ações de prevenção e mitigação sejam realizadas de forma efetiva. O presente estudo teve como objetivo diagnosticar o lixo marinho na faixa de areia da Praia de Navegantes/SC quanto a sua composição e abundância, suas possíveis fontes, bem como a ocorrência de pellets plásticos, buscando ao final do estudo resultados que venham a contribuir para os órgãos ambientais locais definirem melhores ações de prevenção e mitigação do lixo marinho, como a elaboração de uma coleção didática de lixo marinho como ferramenta de educação ambiental. Foram identificados 509 itens, sendo a grande maioria dos itens representados por detritos plásticos (464 itens). Foram também observados um total de 50 pellets plásticos. A proximidade com os portos de Itajai e Navegantes permite considerar a atividade portuária como uma das possíveis fontes desses pellets. As prováveis origens dos resíduos foram em grande maioria “Usuário de praia”, seguido de “Origem indeterminada”. Para a elaboração da coleção didático-científica de lixo marinho optou-se pelo formato digital através das coleta de informações, dados, detritos marinhos e imagens feitas durante as amostragens.

The determinants of consumer engagement in restaurant food waste mitigation in Poland: An exploratory study

Abstract The growing magnitude of restaurant food waste undermines the environmental sustainability of the global sector of food service provision. The challenge of restaurant food waste is of particular concern for transitional and developing economies where food consumption out of home is becoming increasingly popular. In these markets, a large share of restaurant food waste comes from customer plates, which highlights changes to consumer behaviour as an important mitigation opportunity. Little is however known about how these behavioural changes can be activated and subsequently reinforced. This study explores the prerequisites of consumer involvement in mitigating restaurant food waste in Poland, a transitional economy in East-Central Europe. It tests the role of such prerequisites of pro-environmental consumer behaviour as public environmental knowledge, environmental concern, anticipated regret and pro-environmental behaviour at home in shaping positive customer attitudes towards the need to mitigate restaurant food waste with a subsequent trigger of behavioural intentions to engage in mitigation. The study offers policy and management recommendations on how these behavioural intentions can be reinforced.

Characterization of Aged Li-Ion Battery Electrodes for Direct Recycling Process Design

Developing a recycling protocol for lithium-ion batteries (LIBs) at their end of life is crucial to both supply chain stability and waste mitigation. Novel nondestructive recycling methods are under investigation, but lack the process engineering specifications required for full-scale operation. Specifically, the ability of end-of-life LIB components (i.e., recycling feedstock) to withstand the mechanical stresses inherent in industrial reprocessing techniques has not been established. To this end, we have mechanically characterized the electrodes of both fresh cells and “cycled-aged” (C-A) cells (cells that have been cycled and subsequently calendar-aged, and thus reflect a representative recycling input). We report the components’ performance under uniaxial tensile stress and compressive loads, and determine the effects of tensile strain rate and electrode coating on mechanical response. Further, we explore how these measured mechanical properties affect design parameters for a roll-to-roll (R2R) direct recycling process. Cycle-aging is found to significantly reduce the tensile strength of coated electrodes across all strain rates, and electrodes are found to have significantly lower elastic moduli than their respective current collectors. Positive strain rate dependence is observed for bare current collectors but not for coated electrodes, implying that the coating of active material permanently alters the current collector matrix. Compressive failure is not observed for any of the samples; however, C-A cathodes reach elastic deformation at a lower strain than do fresh cathodes. In the context of direct recycling, these findings suggest that roll tension may need to be reduced by 13-65% for C-A components relative to fresh components to avoid irreversible damage. Additionally, C-A cathodes are expected to permanently deform at a lower calendering force than fresh cathodes. Finally, we have investigated each component’s contribution to overall cell capacity loss, and have probed the degradation mechanisms of cathodes to inform recycling method development. Electrochemical analysis suggests that phase shift (layered to spinel phase) and buildup of electrolyte residues at both the primary particle and in the inter-particle pore space may significantly contribute to cathode degradation. Washing C-A cathodes with aprotic solvents is found to improve half-cell cycling performance, likely due to the removal of electrolyte residues, but does not reverse structural degradation. These electrochemical results suggest the importance of a washing step prior to chemical relithiation in direct recycling methods. Thus the present work, which combines mechanical and electrochemical analyses of cycle-aged LIB components, informs the process design of industrial-scale nondestructive LIB recycling.

Investigating Wastage and Associated Mitigation Scenarios Across Fresh Potato Supply Chains in the UK: A Critical Literature Synthesis

Wastage across agrifood supply chains (SCs) is inherently associated to high environmental pressures considering the natural resources’ appropriation and the impacts resulting from the use of inputs like fertilisers, pesticides and energy. Furthermore, in agrifood supply networks, post-harvest treatment operations (i.e. transportation, storage, processing, packaging, refrigeration) are documented as substantial contributors to environmental impact. In this sense, agrifood wastage implies both resource appropriation and in vain environmentally relevant impacts. Except for the environmental impact, the significance of mitigating losses across agrifood SCs is further highlighted by associated ethical implications. Fresh potatoes comprise an interesting case of agrifood products as they are claimed to be one of the commodities with the highest wastage rates. Indicatively, about 53% of the total fresh potatoes’ production for direct human consumption in Switzerland is wasted, while in the United Kingdom (UK) estimates highlight losses as high as two-thirds of all produced fresh potatoes. Therefore, the threefold aim of this study is to: (i) map the end-to-end potato SC, (ii) identify waste hot-spots, and (iii) identify and explore best waste mitigation scenarios which are or could be effectively applied to akin food product supply networks.

Smart energy solution for an optimised sustainable hospital in the green city of NEOM

Hybrid optimisation of multiple energy resources has been performed on a micro grid model of a hospital to investigate the capability of a standalone energy system and simultaneous mitigation of hospital waste. The main objectives of this study were to collect renewable energy resource data of a hybrid hospital, use the average amount of hospital waste from the literature and NASA surface meteorology in addition to the solar energy database from HOMER Pro software to construct a hybrid model for a conceptual hospital in the new green city in Saudi Arabia, NEOM. The hybrid model consisted of biogas cofire and diesel generators, PV solar array and batteries. Simulations were performed to analyse the load requirements of a standalone hospital. The mechanism of energy storage was designed based on Tesla batteries. Then, the hybrid hospital model was tested with NEOM’s natural resources, load demand of 250 kWh/day and the average amount of daily hospital waste of 0.6 tons based on the literature data. This condition allows the smart hospital to be tested with real features. The outcome of the COE, NPC and the amount of reduction of carbon dioxide in the hybrid hospital were analysed. Many of the hybrid properties and constraints that define the hospital were adopted from previous literature concentrating on similar domains. The optimal solution of a hybrid micro grid consisted of biogas cofire, PV array, and batteries. Of the total load demand, 32.3% and 67.6% were produced by PV array and biogas cofire generators, respectively, together with eight Tesla PowerWall2.0 batteries. The cost of energy was 0.21 USD/kWh and the net present cost was 243,699.17 USD. In this study, we compared renewable energy with conventional energy and found that the optimal solution would be able to reduce carbon emission and diesel consumption by almost 84% and 81%, respectively. The results were verified through a sensitivity study and compared with other studies.

A biorefinery for valorization of industrial waste-water and flue gas by microalgae for waste mitigation, carbon-dioxide sequestration and algal biomass production

Massive industrialization all over the globe is the main cause for the generation of huge quantity of wastes such as flue gas and wastewaters. Mindless release of these hazardous wastes into the environment is threatening the health and survival of the mankind. Judicious use of these wastes for microalgal biomass cultivation is recognized as a plausible approach for the creation of a renewable and sustainable process chain for biofuel production. This study was designed to cultivate microalgae utilizing the organic and inorganic nutrients from the industrial wastewater (IWW) and coal-fired flue gas (FG) for simultaneous waste bio-remediation and biomass production for biorefinery application in closed photobioreactors. The two microalgae, Chlorella sp. and Chlorococcum sp. were cultivated in industrial wastewater where varying concentrations of coal-fired FG from 1 to 10% CO2, volume/volume percent (v/v) was supplied to stimulate the mixotrophic growth. Performance of the two microalgae was evaluated in terms of nutrient removal (ammonium, nitrate, phosphate and COD), CO2 fixation, total lipid and carbohydrate content obtained in the integrated mode of process development. The IWW with flue gas (5% CO2 (v/v)) resulted in maximum growth and CO2 fixation. The highest biomass growth (1.52 g L−1) and CO2 fixation (187.65 mg L−1 d−1) of Chlorella sp. with nutrient removal of >70% was observed by 5th day of batch cultivation. Nearly 90% removal of nitrogen resulted in nutrient limitation condition that steered the accumulation of lipid (17–34%) and carbohydrate (21.5–23.1%) in Chlorella and Chlorococcum sp. An overall 1.7 fold improvement in biomass was observed in this process integration compared with control culture. The present study presents a green process for waste remediation, CO2 fixation and production of biomass rich in lipid & carbohydrate content for the development of a green microalgal biorefinery.

Exploitation of Algal-Bacterial Consortia in Combined Biohydrogen Generation and Wastewater Treatment

Microalgae cultivation in municipal, industrial and agricultural wastewater is an emerging, highly effective approach for resource recovery and concomitant bioenergy generation. Wastewater effluents represent ideal sources of nutrients for eukaryotic green algal species. However, the performance of photosynthetic green algae is strongly dependent on the associated bacterial partners present in the effluents. Our combined wastewater treatment and biohydrogen evolution approach applied green microalgae-based photoheterotrophic degradation using dark fermentation wastewater effluent as substrate. The results showed that condition-dependent mutualistic relationships between the microbial and Chlorella algae populations had direct impact on the biodegradation efficiency and also on algal biohydrogen production. Metagenome analysis of the novel hybrid biodegradation system together with total nitrogen and phosphorous analytics provided important clues for the primary importance of the green algae partner in nitrogen and phosphorous removal. Bacterial bin genome data also indicated algal growth promotion by bacterial partners. With further development and optimization this new approach can lead to a highly efficient simultaneous organic waste mitigation and renewable energy production technology.

Managing Your Supply Chain Pantry: Food Waste Mitigation Through Inventory Control

In this paper, we report through case study findings that the food supply chain can be improved by implementing a proper inventory control policy. The case study involves an online retailer who sells predominantly food products. The improvement of the case company is shown via simulation in economic, social, and environmental aspects. The findings indicate the role of supply chain risk as an obstacle in achieving supply chain sustainability, and the benefit of effective inventory control as a cost-advantageous and easy-to-implement waste reduction method.