Disposal Scenarios Research Articles

Sustainability Assessment of Coffee Silverskin Waste Management in the Metropolitan City of Naples (Italy): A Life Cycle Perspective

The use of renewable biological resources, including biowaste, within a circular framework, is crucial for the transition to more sustainable production and consumption patterns. By means of life cycle assessment and life cycle costing methodologies, this study compares the environmental and economic performances of two disposal scenarios for coffee silverskin, the major waste from coffee roasting. The business-as-usual (BaU) scenario, currently applied in the Metropolitan City of Naples (Italy), involves silverskin composting, while the proposed alternative scenario explores the valorization of silverskin as a functional ingredient in bakery products. The alternative scenario results are more advantageous since replacing flour with silverskin in bakery products reduces environmental impact by 96% more than replacing synthetic fertilizers with compost in the BaU scenario. Furthermore, in the alternative scenario, coffee roasters halve their silverskin disposal costs, compared to the BaU scenario (447.55 € versus 190.09 €, for 1 ton). Finally, the major environmental burdens are resource use for equipment construction (37% for BaU, 62% for alternative, on average) and electricity consumption (30% for BaU, 67% for alternative, on average), while the highest economic cost is due to personnel (58% for BaU, 88% for alternative, on average).

Research on revision of relevant provisions of high-speed railway emergency disposal in the regulations on railway technical management (RRTM)

PurposeThis study aims to improve the rules and regulations system of high-speed rail emergency disposal.Design/methodology/approachBased on the analysis of the demands, rules and regulations of China concerning on-site high-speed rail emergency disposal, basic principles for revising the regulations on railway technical management (RRTM) are proposed and suggestions and evaluation methods according to the main clauses are put forward.FindingsBasic principles for revising the RRTM are proposed, namely “to meet the actual needs of on-site high-speed railway emergency disposal, standardize the emergency disposal process, improve the efficiency of emergency disposal and keep the consistency between provisions of emergency disposal”. Existing provisions related to emergency disposal efficiency, scenarios, safety and service quality are made up for the deficiencies. To make up for the deficiencies of the existing provisions related to emergency disposal efficiency, improvement of emergency disposal scenarios and guarantee of emergency disposal safety and quality, this paper puts forward suggestions on revising 15 emergency disposal provisions of the RRTM with regard to earthquake monitoring and warning, in-station foreign body invasion warning, air conditioning failure of EMU trains and forced parking of trains in sections. A fuzzy comprehensive evaluation model based on the analytic hierarchy process (AHP) is constructed to evaluate the proposed revision scheme and suggestions, which has been highly recognized by experts.Originality/valueThis study implements the goal of high-quality railway development.

An electric model for bare-photovoltaic tethers in the passive mode

A bare-photovoltaic tether (BPT) is a long conductive tape in orbit that provides propellant-less propulsion and power harvesting. An electric model for a BPT operating in the passive mode and composed of a bare segment and a bare-photovoltaic (bare-pv) segment coated with thin-film solar cells on one side is presented. The pv cells, which are electrically insulated from the conductive substrate, are connected to two electric busbars that also serve as electrical contacts to the spacecraft. The power harvested by the cells can be used by the spacecraft or, as considered in this work, to boost tether performance. The electric model takes into account that, depending on the number and location of zero-bias points, four regimes of operation exist for this type of BPT. Current and voltage profiles solutions that are not possible for standard bare tethers are presented. A parametric analysis of the operation regimes varying the tether length, the length of the pv segment, and the power was carried out. Two complementary methods to find the optimum length of the bare-pv segment for a given total tether length and mission are presented. The first method is based on the optimization of the normalized average current, which controls the strength of the Lorentz force and measures tether efficiency and the second method uses as figure of merit the deorbit time in postmission disposal scenarios. For both of them it is shown that an optimum exists for the length of the pv segment. An enhancement in performance above 30% as compared with standard bare tethers was found for the considered scenario.

Mechanical and microstructural evolution of solidified/stabilized heavy metal-contaminated soil under a hydro-chemical-mechanical coupling environment

The long-term effectiveness of Solidification/Stabilization (S/S) under realistic disposal scenarios is a common controversy of its application. This study sought to investigate the evolution of the mechanical properties and microstructure of Pb-Zn-Cd composite contaminated soil solidified/stabilized by cement and fly ash (CSCS) under a hydro-chemical-mechanical coupling environment (HCM). An HCM simulation system was developed to reproduce the simultaneous action of hydraulic, chemical, and stress environments on CSCS. The mechanical and microstructural evolution of CSCS under HCM was assessed using vertical settlement monitoring, unconfined compressive strength (UCS) test, computed tomography (CT), mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The increasing environmental acidity induces an increase in vertical displacement and a decrease in UCS. The highest final settlement was 0.96 mm at pH 3 and a pressure of 250 kPa, which was 39.13 % greater than the value at pH 5 and 7. The UCS decreased by 18.54 % after 168 h of HCM treatment at pH 7, while the value reached 45.83 % when the pH was lowered to 3. Seepage contributes to initial hydration as evidenced by an increase in the early E50 of the CSCS. Hydrodynamic scouring and chemical erosion increase the pore size and deteriorate the soil structure, whereas compaction helps to redistribute soil particles, thus improving the structural integrity and uniformity of the CSCS.

An Air-Ground Coordinated Sensing, Relay and Offloading for Emergency Disposal in ITS System

Nowadays, the Unmanned Aerial Vehicle (UAV) has emerged as a powerful platform for diversified application development. In traffic areas specifically for the much-anticipated Intelligent Transportation System (ITS), UAVs can coordinate with the ground internet of things infrastructure, such as the Road Side Unit (RSU), to perform 3D data collection and processing, improving traffic safety and transportation efficiency. In ITS, decision-making is crucial and relies heavily on proper and timely processing and transmission of the massive amounts of data generated by ubiquitous sensors, especially in emergency disposal scenarios. In this paper, the latency incurred from RSU-aided data offloading and UAV-aided data relay plays a decisive role, characterized by both the average and risk performance metric, Conditional Value at Risk (CVaR), for quantifying the risk incurred from the latency violation over a certain threshold in probability. Specifically, the peak Age of Information (AoI) with its distribution is adopted to underlying the CVaR analysis in relay latency. Besides, the matching algorithm to coordinate the mutual transmission between UAVs and RSUs is proposed, achieving low computation complexity and minimum risk for both sides. The system performance is validated through analysis, simulation, and field experiments.

BARIK: an extended Hoek–Brown-based anisotropic constitutive model for fractured crystalline rock

Abstract. The disposal of heat-generating radioactive waste in deep geologic formations is a global concern. Numerical methods play a key role in understanding and assessing the disposal scenarios of radioactive waste in deep geological repositories. However, the complexities of the thermal, hydrological, mechanical, chemical, and biological processes associated with the disposal of radioactive waste in porous and fractured materials constitute significant challenges. One of the most challenging issues in this field is the complex material behavior of fractured crystalline rock. The presence of fractures makes the rock anisotropic, nonlinear, and dependent on loading paths. Additionally, the Biot coefficient cannot be considered constant throughout the critical and subcritical fracture development regions. These factors make the development of an accurate constitutive model for fractured crystalline hard rock a critical component of any deep geological disposal project. Furthermore, to demonstrate the integrity of the containment-providing rock zone in crystalline host rock, the qualitative integrity criteria must be quantified so that numerical simulation can be performed with concrete numerical values. Part of this assessment for a crystalline host rock is a dilatancy criterion, which is currently based on the Hoek–Brown constitutive model. BARIK is the German acronym for the research project on which this paper is based. This contribution provides an overview of the development and verification of the BARIK constitutive model, an extended Hoek–Brown model for fractured crystalline hard rock that takes into account up to three fracture systems. The model enables the consideration of the matrix and joint behavior of the rock separately, with each component having unique strength characteristics and failure criteria. These criteria are formulated such that suitable consideration of the strength-reducing properties of the respective fracture systems during barrier integrity verification is possible. The BARIK model has been implemented into two computer codes, FLAC3D and MFront for OpenGeoSys, allowing for the identification and evaluation of any inaccuracies that may arise from the use of different codes. The model enables isotropic–elastic, orthotropic–elastic, isotropic–elasto-plastic, and orthotropic–elasto-plastic calculations of the matrix, making it a valuable tool for the site selection process and for the construction and long-term safety of underground repositories. Furthermore, this poster presentation will show how the constitutive model was evaluated in relation to the dilatancy criterion and how the BARIK constitutive model's suitability for conducting an integrity assessment was validated. In conclusion, the development of BARIK is a significant step forward in the understanding and modeling of the complex material behavior of fractured crystalline hard rock. This contribution will provide insights into the development and verification of this model for the safe disposal of radioactive waste.

BARIK: laboratory programme within the framework of the development of an extended Hoek–Brown-based anisotropic constitutive model for fractured crystalline rock

Abstract. The disposal of heat-generating radioactive waste in deep geologic formations is a global concern. Numerical methods play a key role in understanding and assessing the disposal scenarios of radioactive waste in deep geological repositories. However, the complexities of the thermal, hydrological, mechanical, chemical, and biological processes associated with the disposal of radioactive waste in porous and fractured materials constitute significant challenges. One of the most challenging issues in this field is the complex material behaviour of fractured crystalline rock. The presence of fractures makes the rock anisotropic, nonlinear, and dependent on loading paths. Additionally, the Biot coefficient cannot be considered constant throughout the critical and subcritical fracture development regions. These factors make the development of an accurate constitutive model for fractured crystalline hard rock a critical component of any deep geological disposal project. Furthermore, to demonstrate the integrity of the “containment effective rock area” in crystalline host rock, the qualitative integrity criteria must be quantified so that numerical simulation can be performed with concrete numerical values. Part of this assessment for a crystalline host rock is a dilatancy criterion, which is currently based on the Hoek–Brown constitutive model. This contribution provides an overview and first results of the laboratory programme, which was performed as a part of the research project. The aim was to generate a fundamental and extensive dataset for an anisotropic material used for verification and validation purposes of the newly developed constitutive model. The rock material for the test programme was “Freiberger gneiss” because of its pronounced anisotropic properties regarding deformation and strength as well as the good access to obtain a larger amount of sample material. A wide range of basic tests have been performed, e.g. determination of density and porosity, measurement of ultrasonic wave velocities to get dynamic elastic properties, Brazilian tests, and uniaxial compression tests to obtain strength data. Additionally, a large number of more complex multi-stage triaxial compression tests with examination of the post-failure region and hydromechanical coupled triaxial compression tests have been conducted or are in progress. The hydromechanical part, in particular, plays an important role in examining and quantifying the evolution of the micromechanical damage process, which changes the permeability and Biot coefficient and therefore the effective stresses inside a saturated rock material. Tests were conducted with different orientations of the structural planes in relation to the loading directions.

An Integrated Framework for Environmental and Social Life Cycle Assessments in PET Bottle Waste Management: A Case Study in Brazil

The improper disposal of PET bottle waste in Brazil jeopardizes the sustainability goals, impacting the social, economic, and environmental aspects. In order to tackle this issue, this study introduces a framework that was developed using a combination of environmental and social life cycle assessments (LCAs), along with a modified Analytic Hierarchy Process (AHP) methodology. Nine disposal scenarios were evaluated in Bauru, Brazil, including various combinations of landfills, sorting cooperatives, and incineration. Environmental (Env-LCA) and social (S-LCA) assessments followed the ISO 14040 standards, with the S-LCA incorporating the UNEP/SETAC guidelines. Scenario 9 was identified as the most sustainable option from the evaluated scenarios, with 100% of the waste sent to sorting cooperatives, with modified collection schemes. Conversely, Scenario 1, with a high landfill percentage, proved to be the least sustainable.

System Dynamics Modeling for Effective Strategies in Water Pollution Control: Insights and Applications

Water pollution is a significant environmental challenge with implications for both the natural world and human well-being. To better understand and manage the complex interactions within water pollution systems, such as waste dumping in the sea, system dynamics modeling has emerged as a valuable tool. This simulation-based approach employs feedback loops and cause-and-effect relationships to capture the dynamic behavior of such systems over time. By simulating various waste disposal scenarios and assessing their impacts on the environment and human health, system dynamics modeling aids policymakers and waste managers in devising effective strategies for the sustainable management of dumping sites into the sea. In this manuscript, we present a system dynamics approach to model water pollution control. Our study entails the development of a conceptual model that encompasses pollution sources, pollutant transport and fate, and their effects on water quality and human health. By calibrating and validating the model using data from a case study in Charleston Harbor, South Carolina, United States, we ensure its accuracy and reliability. The results highlight the model’s versatility in simulating different pollution control scenarios, particularly those involving dredging discharge and powerhouse effluent. Through these simulations, we gain valuable insights into the potential impacts of various pollution control measures on water pollution dynamics. Our research underscores the significance of system dynamics modeling in comprehending intricate water pollution systems, including those associated with waste dumping in the sea. By identifying effective strategies for water pollution control, this approach offers invaluable support in safeguarding marine ecosystems and human communities. In conclusion, system dynamics modeling proves to be a powerful tool for sustainable water pollution management. This research demonstrates its utility in analyzing dumping sites in the sea and provides essential findings to inform effective pollution control strategies. Emphasizing the broader context of water pollution, this study contributes to advancing knowledge and fostering sustainable practices to protect our precious water resources.

Integrating eco-environmental assessment with energy recovery for petrochemical wastewater treatment technologies: A transition towards green and sustainable management

The petrochemical industry is a significant source of hazardous waste, leading to widespread environmental pollution. For the first time, an integrated approach was employed in the current study to combine life cycle assessment (LCA) coupled life cycle cost (LCC) analysis with waste sludge disposal scenarios to evaluate trickling filter (TF), membrane bioreactor-reverse osmosis (MBR-RO), and integrated fixed-film activated sludge-membrane bioreactor (IFAS-MBR) performance at the individual unit level for the treatment of petrochemical wastewater. The midpoint LCA modeling indicated that the main environmental burdens in the studied systems were freshwater eutrophication (<5.31 kg P eq) and toxicity potentials (<263.16 kg 1,4-DCB). These impacts were primarily attributed to the emissions of zinc, copper, nickel, and the processing of heat and gas. Furthermore, the results of the LCC analysis revealed that the TF system was more cost-effective than the MBR-RO and IFAS-MBR systems. By utilizing the produced biogas for energy provision in the TF system, significant reductions in toxicity potentials and ecosystem impact categories ranging from 26.72 % to 56.69 % were observed. Additionally, the biowaste scenario exhibited lower environmental concerns (<50 %) compared to incineration or landfill. In conclusion, this investigation provides valuable perspectives and a sustainable strategy for future policymaking regarding petrochemical wastewater treatment.

Extensive comparison of methods for removal of organic halogen compounds from pharmaceutical process wastewaters with life cycle, PESTLE, and multi-criteria decision analyses

Recycling and disposing wastewater from the pharmaceutical industry are of utmost importance in mitigating chemical waste generation, where unmanaged hazardous waste fluxes could cause massive environmental damage. Air stripping, steam stripping, distillation, and incineration offer significant emission reduction potentials for pharmaceutical applications; however, selecting specific process units is a complicated task due to the high number of influencing screening criteria. The mentioned chemical processes are modelled with the Aspen Plus program. This study examines the environmental impacts of adsorbable organic halogens (AOX) containing pharmaceutical process wastewater disposal by conducting life cycle impact assessments using the Product Environmental Footprint (PEF), IMPACT World + Endpoint V1.01, and Recipe 2016 Endpoint (H) V1.06 methods. The results show that the distillation-based separation of AOX compounds is characterized by the most favourable climate change impact and outranks the PEF single score of air stripping, steam stripping, and incineration by 6.3%, 29.1%, 52.0%, respectively. The energy-intensive distillation technology is further evaluated by considering a wide selection of energy sources (i.e., fossil fuel, nuclear, solar, wind onshore, and wind offshore) using PESTLE (Political, Economic, Social, Technological, Legal, Environmental) analysis combined with multi-criteria decision support to determine the most beneficial AOX disposal scenario. The best overall AOX regeneration performance and lowest climate change impact (7.25 × 10−3 kg CO2-eq (1 kg purified wastewater)−1) are obtained by supplying variable renewable electricity from onshore wind turbines, reaching 64.87% carbon emission reduction compared to the baseline fossil fuel-based process alternative.

Life cycle assessment studies to evaluate the sustainability of various facemasks used during COVID-19: A UAE case study

The major hurdle in recovering from the COVID-19 pandemic would be the safe management of plastic waste generated from personal protective equipment and mitigating a plastic pollution crisis. Facemasks were adopted worldwide as the first line of defense against the COVID-19 pandemic, and their demand increased exponentially during the last few years. Through a life cycle assessment, this study aims to evaluate the environmental impacts of various facemasks available in the UAE market. SimaPro software was used to conduct a cradle-to-grave LCA, with a functional unit of "The number of face masks required by a person in UAE over a month (30 days)". Results show that the GWP (in kg CO2 eq) of 1 FU of surgical FM is 0.867, activated carbon FM is 1.11, N95 FM is 1.55, cloth FM is 0.642, and PLA FM is 0.946. Packaging increases the GWP by 36–178%. Long-distance transportation from China to UAE was identified to be a significant hotspot under GWP and FRS. Other hotspots include polypropylene material in filtration layers, aluminum in nosepieces, electricity usage in cloth masks, and disposal scenarios. Multiple supply chain optimizations are suggested, such as the substitution of recycled aluminum in nose pieces, the use of sustainable transportation, and limiting the use of packaging material to a bare minimum to improve the sustainability of the face mask industry.

Patients prefer free drug disposal options delivered by pharmacists at the point of care: Results of a decision tree analysis of a national factorial vignette panel survey.

Unused opioid medication in the home increases risk of medication diversion, misuse, and unintended harm. The United States Federal Food and Drug Administration is currently considering the implementation of a risk evaluation and mitigation strategy (REMS) program that would require US pharmacists to provide drug disposal products with opioid prescriptions. Still, little is known about consumer preference for drug disposal method. The objective of this study was to identify product and program characteristics associated with consumer preference for at-home drug disposal products. A 2x2x3x3 full-factorial design was employed to text-based vignettes representing opioid analgesic disposal scenarios. Each vignette varied on four characteristics: product cost (free vs paid), ease of use (a mail back envelope, bringing medication to a takeback site, and an at-home drug deactivation pouch), potential environmental impact (incineration), and point of access (pharmacy, community organization, and prescriber). Of the 36 possible vignettes, 12 were removed as they represented a non-realistic combination of vignette characteristics. The remaining 24 were administered to a panel of patients with controlled-substance use in the past six-months. Decision tree modeling and general linear mixed (GLM) models were used sequentially to identify product characteristics associated with patient drug preferences RESULTS: A total of 1,006 participants completed all vignette drug disposal scenarios. Regression tree analysis found that the most important predictor of use was cost followed by ease of access and product design. GLM showed that takeback programs offered at a pharmacy were the most preferred disposal option followed by at-home products (mailed envelope or deactivation system) dispensed with the prescription. Programs that provide disposal resources directly to the patient at no cost with their prescription are likely to optimize willingness to dispose. Findings support the FDA's plan for a REMS program requiring pharmacies to distribute mail-back envelopes to patients when dispensed opioids.

Thermal hydrolysis of sewage sludge: Improvement in biogas generation and prediction of global warming potential.

Anaerobic digestion (AD) is a prominent treatment method for the sludge produced from sewage treatment plants. Poor solid reduction and longer retention time are the main drawbacks of AD. Thermal hydrolysis (TH) is a potential pretreatment method for solubilization of sewage sludge (SS) solids thereby improving biogas production during AD post-treatment. In this study, the SS sample (total solids = 1.75 wt% and total chemical oxygen demand (COD) = 15,450 mg L-1) was subjected to TH pretreatment (temperature = 140-180°C and reaction time = 60 minutes) in a 0.7-L capacity stainless-steel high-pressure reactor. At a reaction temperature of 180°C, the maximum solid solubilization (total dissolved solids = 4652 mg L-1) and improved dewaterability (time to filter = 4.7 s.L g-1) were observed. The biochemical methane potential test results showed almost doubling of methane generation from 145 to 284 mL gCOD-1 after TH pretreatment at 180°C. The life cycle assessment approach was used to compare various SS treatment and disposal scenarios, two of which included hydrothermal pretreatment. The scenarios involving hydrothermal pretreatments showed the least global warming potential.

Ozonation Vs sequential solar driven processes as simultaneous tertiary and quaternary treatments of urban wastewater: A life cycle assessment comparison

Solar driven advanced oxidation processes (S-AOPs) have been successfully investigated in the last years as tertiary and quaternary treatment of urban wastewater for simultaneous inactivation of microorganisms and removal of contaminants of emerging concern (CECs), respectively. However, the lack of data about the comparison with consolidated technologies, including also the evaluation of their impact on the environment, has contributed to humper their application at full scale so far. In this study, the environmental impact of a new S-AOP, namely sequential treatment (ST) with sunlight/H2O2 and solar photo-Fenton (SPF) at neutral pH (using Ethylenediamine-N, N′-disuccinic acid (EDDS) as chelating agent) operated at pilot scale in a raceway pond reactor, was compared to a pilot scale ozonation (O3) treatment unit in terms of simultaneous bacteria inactivation and CECs removal, through a Life Cycle Assessment (LCA). Different urban wastewater treatment plant (UWWTP) sizes and scenarios (namely effluent disposal and reuse) were evaluated. While the reuse scenario resulted in a higher impact compared to the disposal scenario in the construction/deconstruction phase, due to the more stringent limits that resulted in longer treatment time and a higher consumption of raw materials, the positive impact on water resources saving compared to disposal makes the reuse scenario a more sustainable solution. Despite O3 disinfection by-products were taken into account, ST resulted in a higher toxicity to human health (0.27·10−9 DALYs Vs 2.11 10−9 DALYs, respectively) due to the higher residual concentration of the target CECs. However, it is noteworthy that both values are significantly lower than the acceptable DALYs value (≤10−6). Chemicals, energy, groundwater consumption and residual CECs can affect resources 1125 and 1874 times more for O3 treatment than for the ST, for disposal and reuse scenarios, respectively. The total impact of O3 on the human health was 13 and 19 times higher compared to ST, for disposal and reuse scenarios, respectively, due to the higher energy and chemical consumption. According to the LCA results, ST resulted in a better overall environmental performance compared to O3 and it is a more sustainable and attractive solution in particular for small UWWTPs.

Solid Waste Disposal Scenario of Three Ladies’ Halls in the University of Chittagong, Chattogram, Bangladesh

University of Chittagong (CU) is well known for its beautiful green campus. It had 11 student halls (plus two were under construction), of which three were ladies’ halls named (Shamsun Nahar, Pritilata and Deshnetri Begum Khaleda Zia). But, due to lack of a proper waste management plan, wastes were found to be scattered in open areas of ladies’ halls premises. So, to protect the environmental quality of three ladies’ halls a research work has conducted during June 2012 to March 2013. Here researcher try to determine the waste generation rates, their physical composition and characterized them. At that time data about disposed wastes were collected weekly from kitchen, dining, canteen, bathroom, and halls premises at 8.00 to 11.00 am and wastes were measured by using weighing machine in kilogram (kg). Based on sources, wastes were categorized mainly on four types, such as: (1) kitchen waste, (2) dining and canteen wastes, (3) bathroom waste, and (4) others (veranda, corridor, and in and around the halls’ campus) wastes. Overall, 18,505.0 kg wastes were disposed from different sources and among them 10,406.0 kg (i.e., 56.24%) were from kitchen, 1,218.5 kg (i.e., 6.59 %) from dining and canteen, 1,570.5 kg (i.e., 8.49 %) from bathroom and 5,310.0 kg (i.e., 28.68 %) from others sources. On an average each student of 3 ladies’ halls disposed 0.029 kg waste per day that gave a total of 8.520 kg wastes during the 10 months of study period. The campus of The University of Chittagong is well known as a habitat of different types of wild animals. So, monthly waste dumping sites were visited and the wild animals those were seen eating foods from dumping wastes were identified with the help of field guides (Section e.g., Grimmett et al., 2009; Ahmed et al., 2009).

Landfill Codisposal of On-Site Vegetation and Coal Combustion Residuals: Implications for Gas Management

Historically, ash from coal combustion has been disposed of in ponds that were not designed with engineered containment systems. As a result of regulatory changes, it is estimated that coal combustion residuals (CCRs) from hundreds of unlined ponds will have to be excavated and disposed of in new lined landfills or the existing CCR ponds will have to been closed in-place with an engineered final cover system. The excavated or in-place CCR may contain vegetative matter that has the potential to decompose to CH4 and CO2. The objective of this study was to demonstrate a framework to assess the need for a gas collection system to accommodate the disposal of a mixture of CCR and vegetation in a lined landfill. Methane generation rates and yields for vegetative matter mixed with CCR were measured in biochemical methane potential and specific methane activity tests at 15, 20, and 37 °C. The data were then used to parameterize a methane generation model to estimate the gas flux at the landfill surface for a series of hypothetical disposal scenarios. Results showed that the specific decay rate constant (k) ranged from 0.00037 to 0.00872 yr–1, while the methane yield (L0) ranged from 84 to 120 mL CH4/dry g. Temperature was the most important determinant of the decomposition behavior. Simulations of gas flux for several disposal scenarios showed that the modeled flux from the decomposition of vegetation was below the CH4 and CO2 transmission rates reported for a geomembrane liner final cover system, suggesting that an active gas collection will not be necessary under the modeled disposal conditions.

Integration of photovoltaic panels and solar collectors into a plant producing biomethane for the transport sector: Dynamic simulation and case study

In the current energy and environmental framework, the environmental impact of the road transport sector and the urban waste management and disposal are extremely important for highly crowded cities. This work assesses the energy, economic and environmental performance of an innovative paradigm for the full decarbonisation of the road transport sector. This problem is integrated with the management of the organic fraction of municipal solid waste. In particular, the proposed technology is based on an anaerobic digestion plant coupled with a biogas upgrading unit, for the production of biomethane. In addition, photovoltaic panels and solar thermal collectors are also considered for matching electrical and thermal demands, in order to achieve a fully-renewable system. To this scope, the system also includes suitable thermal and electric storages. The economic analysis also considers specific public funding policies, currently available for this technology. This system aims to be a novel paradigm in the energy scenario of waste disposal and road transport sector refurbishment. TRNSYS software was adopted to perform an accurate dynamic simulation for a one-year operation of the system. The anaerobic digestion model is developed by the authors in MatLab and integrated in TRNSYS, for dynamic simulation purpose. Results show that the plant is almost self-sufficient due to the integration of storage systems for both the thermal and electric energy. The photovoltaic system is able to reduce by 45% the energy dependence from the grid. Energy and environmental analyses show a Primary Energy Saving of 126% and a reduction of CO2 equivalent emissions by 112%. The economic feasibility analysis shows a promising Simple Payback period of 6 years.

Carbon footprint assessment of a wood multi-residential building considering biogenic carbon

Wood and other bio-based building materials are often perceived as a good choice from a climate mitigation perspective. This article compares the life cycle assessment of the same multi-residential building from the perspective of 16 countries participating in the international project Annex 72 of the International Energy Agency to determine the effects of different datasets and methods of accounting for biogenic carbon in wood construction. Three assessment methods are herein considered: two recognized in the standards (the so-called 0/0 method and −1/+1 method) and a variation of the latter (−1/+1* method) used in Australia, Canada, France, and New Zealand. The 0/0 method considers neither fixation in the production stage nor releases of biogenic carbon at the end of a wood product's life. In contrast, the −1/+1 method accounts for the fixation of biogenic carbon in the production stage and its release in the end-of-life stage, irrespective of the disposal scenario (recycling, incineration or landfill). The −1/+1 method assumes that landfills offer only a temporary sequestration of carbon. In the −1/+1* variation, landfills and recycling are considered a partly permanent sequestration of biogenic carbon and thus fewer emissions are accounted for in the end-of-life stage. We examine the variability of the calculated life cycle-based greenhouse gas emissions calculated for a case study building by each participating country, within the same assessment method and across the methods. The results vary substantially. The main reasons for deviations are whether or not landfills and recycling are considered a partly permanent sequestration of biogenic carbon and a mismatch in the biogenic carbon balance. Our findings support the need for further research and to develop practical guidelines to harmonize life cycle assessment methods of buildings with bio-based materials.

To Dispose or to Reuse? Analyzing the Life Cycle Impacts and Costs of Disposal, Sterilization, and Reuse of Electrophysiological Catheters

Given the growing ecological footprint of anthropomorphic activities, considering the environmental impacts of any process is becoming increasingly important. This is especially true for the healthcare industry, whose objective of maintaining human health standards is impeded by its own unsustainable practices. To this end, life cycle analysis is particularly helpful. There have not been many life cycle analyses performed on a healthcare device or on medical procedures. Many medical devices are single use, which leads to a significant waste management problem, particularly as plastic is widely used in their composition. The objective of this study is to present a life-cycle-thinking-based approach to compare the environmental impacts associated with single-use electrophysiological catheters with the sterilization of reusable electrophysiological catheters using hydrogen peroxide, ethylene oxide, and peracetic acid. A life cycle assessment was conducted considering different use, disinfection, and disposal scenarios for electrophysiological catheters, using ReCiPe midpoint and endpoint analysis with the SimaPro software. The findings indicate that using single-use disposable electrophysiological catheters, instead of sterilizing a single catheter using either ETO or hydrogen peroxide and reusing multiple times, is preferable from a purely environmental perspective. However, the costs reduce drastically when equipment is sterilized and reused instead of disposing them after using one time. This in turn illustrates that depending on the process, sanitizing and reusing medical devices may not always be more resource-efficient than single device usage. From a cost perspective, ETO sterilization has the lowest costs, and yet it leads to an aggregate environmental impact of over 20 times compared to the single-use scenario, mainly due to the required detoxification process. The outcomes of this research will assist the health care industry in identifying the most suitable operational procedures considering patient safety, economics, and environmental stewardship, and in developing policies and guidelines for a more sustainable healthcare sector.