Waste Treatment Options Research Articles

Waste-to-energy technologies: Integrating anaerobic digestion, microbial electrolysis cells, hydrodynamic cavitation, and electrocoagulation

This study explores a novel integration of electro-physicochemical technologies to generate energy and treat water from combined food waste (FW) and blackwater (FW-BW), with BW containing waste activated sludge with simulated flush water. The FW-BW substrate was gravity-separated and pretreated with hydrodynamic cavitation (HDC). Solids from gravity separation were used for energy generation via anaerobic digestion (AD) alone or integrated with microbial electrolysis cells (AD-MEC). HDC pretreatment had 51.6% more CH4 production in 5 days (266 mL CH4/g VS) and 63% more in 30 days compared to AD without HDC. The CH4 production after 5 days of digestion with HDC pretreatment (266 mL CH4/g VS) was similar to the amount produced without HDC over 30 days (263 mL CH4/g VS). Using MEC increased CH4 production by 12.7% compared to AD-only. The liquids from gravity separation were treated with electrocoagulation (EC) at 15 V (90 min), which removed 96.2% of the chemical oxygen demand (COD) and 100% of the total suspended solids. The pilot scale design indicates that the AD-MEC and EC units would generate 1.4 times more energy than energy consumed through applying these novel technologies. These findings demonstration the applications of four technologies (HDC, AD, MEC, and EC) in an energy-efficient waste management approach, producing bioenergy and cleaner water for low-tier use, especially in areas lacking traditional waste treatment options.

Lifecycle Assessment of Strategies for Decarbonising Wind Blade Recycling toward Net Zero 2050

The wind energy sector faces a persistent challenge in developing sustainable solutions for decommissioned Wind Turbine Blades (WTB). This study utilises Lifecycle Assessment (LCA) to evaluate the gate-to-gate carbon footprint of high-profile disposal and recycling methods, aiming to determine optimal strategies for WTB waste treatment in the UK. While this article analyses the UK as a case study, the findings are applicable to, and intended to inform, recycling strategies for WTB waste globally. Long-term sustainability depends heavily on factors like evolving energy grids and changing WTB waste compositions and these must be considered for robust analysis and development strategy recommendations. In the short to medium term, mechanical recycling of mixed WTB waste is sufficient to minimise Global Warming Potential (GWP) due to the scarcity of carbon fibre in WTB waste streams. Beyond 2040, carbon fibre recycling becomes crucial to reduce GWP. The study emphasises the importance of matching WTB sub-structure material compositions with preferred waste treatment options for the lowest overall impact. Future development should focus on the extraction of carbon fibre reinforced polymer (CFRP) structures in WTB waste streams, commercialising large-scale CFRP structure recycling technologies, establishing supply chains, and validating market routes for secondary carbon fibre products. In parallel, scaling up low-impact options, like mechanical recycling, is vital to minimise WTB waste landfilling. Developing viable applications and cost-effective market routes for mechanical recyclates is necessary to displace virgin glass fibres, while optimising upstream recycling processes based on product requirements.

Wind turbine end-of-life options based on the UN Sustainable Development Goals (SDGs)

The installed wind power capacity is rapidly growing worldwide, and large volumes of waste materials would need to be treated due to the decommissioning of wind turbine systems in the next years. The purpose of the present work is to evaluate the sustainability performance of decommissioning options for wind turbines and suggest policies to improve the sustainability of the wind turbine end-of-life phase by jointly applying Life Cycle Assessment (LCA) and Data Envelopment Analysis (DEA) methodologies. Unlike most of the relevant literature, which focuses mainly on technical aspects of wind turbine decommissioning, the proposed approach considers all three dimensions of sustainability using Sustainable Development Goals (SDGs) as a guide to identify economic, environmental, and social indicators. The methodology is applied to a representative case study of a wind turbine operating in the Greek territory using real data. Repurposing was found to be the most sustainable end-of-life alternative for composite waste. In contrast, the waste treatment option of the foundation concrete contributes substantially to the sustainability performance of the examined scenario. The sustainability performance of these technologies could be enhanced by the operation of dedicated concrete and composite materials recycling facilities close to wind parks, following cross-sectoral approaches. The results also indicate that the social aspects of the sustainability framework are equally important and should be considered when strategies towards more sustainable waste management of wind turbine systems are designed.

Biogas and Biohythane Production from Anaerobic Co-digestion of Canned Sardine Wastewater with Glycerol Waste

A biochemical methane potential (BMP) test investigated the effect of glycerol waste (GW) concentration on anaerobic co-digestion with canned sardine wastewater (CSW). They were studied using the single-stage process at mesophilic (P1) and thermophilic (P2) conditions and two-stage mesophilic (P3) processes. The P3 process has provided the most significant potential for improving biogas production in the sardine canning industry. Using 4% GW (v/v), the optimal hydrogen and methane concentrations at P3 are 43.00 ml H2/g CODr and 303.69 ml CH4/g CODr, respectively. The P3 process was 11.33 m3 biohytane/m3 mixed substrate, and the biohytane composition contained 43.11% CH4, 21.45% H2, and 35.43% CO2. The modified Gompertz model could simulate satisfactory hydrogen and methane yields, corresponding to high regression coefficients (R2>0.90). Hydrogen-producing bacteria in the H2 batch reactor were dominated by Micrococcus sp. and Desulfovibrio sp., while Methanosaeta sp., Methanoculleus sp., and Methanosarcina sp. are the major methanogens in the CH4 batch reactor. A two-stage process of co-fermenting CSW and GW could be a potential option for simultaneous biofuel recovery and waste treatment.

Impact of Implementing Circular Waste Management System and Energy Recovery in a City with 100,000 Inhabitants on Nitrogen Emissions by 2035

Recent years have observed a reconstruction of the waste management system from a linear resource flow economy to a circular economy. This approach is reflected in the provisions of the Waste Framework Directive (2018), which introduces, among others, new recycling targets for municipal waste which require, by 2025, 55% of the municipal waste to be recycled, in 2030—60%, and in 2035—65%. The ambitious targets adopted for preparing for the reuse and recycling of municipal waste will not be achieved without a high level of the recycling of bio-waste. This paper studies the quantification of municipal waste and nitrogen in a circular municipal waste management system (MWM) implemented for a city of 100,000. It was assumed that MWM would meet the requirements in terms of EU and Polish circular waste management goal legislation for the years 2025, 2030 and 2035. The research results showed that the development of a separate waste collection will reduce the waste delivered to MBT. The required MBT capacity will decrease by almost 2.4 times. Moreover, it has been shown that the introduction of a closed-loop MWM will result in an almost two-fold reduction in the amount of nitrogen going to the landfill and an increase in the mass of nitrogen that can be used to fertilize the soil (by approximately 22%). Furthermore, it has been shown that the most favorable option for an organic waste treatment is the anaerobic–aerobic process. This solution provides the highest biogas production and the lowest nitrogen gas emissions to air.

Solutions for recycling emerging wind turbine blade waste in China are not yet effective

Wind power supply chains are evolving as markets expand to reach climate goals. With the largest installed wind power capacity globally, China must deal with increasing composite turbine waste and anticipate its associated costs. Here we predict the quantity and composition of wind turbine blade waste based on historic deployment. A high-resolution database containing 14 turbine capacities (150–5500 kilowatts) was compiled based on 104 turbine models. The environmental and financial costs of waste treatment options were evaluated using a bottom-up approach. Based on current installations and future projections, 7.7 to 23.1 million tonnes of blade waste will be generated in China by 2050. Technologies exist to recycle glass fibre from blade waste, but these solutions vary in level of maturity and are not always commercially available, cost-competitive, or environmentally sustainable. Our findings can inform decision-makers in governments and industry on the pathways to carbon neutrality.

Modelling of air emissions from open burning of municipal waste in Ilorin Metropolis, North Central Nigeria

AbstractIncreased urbanization and population growth have led to a rise in municipal solid waste (MSW) generation, necessitating the need for improved infrastructure and handling methods. Improper disposal practices, particularly open burning at dumpsites, have become common in emerging urban cities, posing serious environmental and health risks. This study aims at evaluating the pollutants often emitted into the environment during the open burning of solid wastes using the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) model under three scenarios. The ground‐level concentrations of pollutants emitted were compared with the statutory limits of the World Health Organization (WHO) at selected receptor locations. The predicted maximum concentrations from the model for PM2.5 were 4184, 8633, and 10,419 μg/m3 and for PM10 were 16,481, 20,915, and 23,114 μg/m3 for scenarios 1, 2, and 3, respectively. The WHO limits of PM2.5 and PM10 were observed to be exceeded from 2500%–17,400% and 312.5%–4200% for scenario three representing the worst‐case scenario. Ilorin metropolis was revealed to be the receptor location with the highest impact. Waste‐to‐energy and other cleaner waste treatment options should be adopted to protect public health and environment.

Treatment Options for Municipal Solid Waste by Composting and Its Challenges.

The online version contains supplementary material available at 10.1007/s12088-023-01087-4.

Co-processing of solid recovered fuels from mixed municipal and commercial waste in the cement industry - A pathway to a circular economy.

With global municipal solid waste generation increasing steadily, the importance of high-quality, environmentally friendly waste valorization methods is rising, too. Most countries have set themselves ambitious recycling goals and follow a waste hierarchy in which recycling is more preferable than energy recovery. This article focuses on a waste treatment option that already is an integral part of waste management in some countries and enables the simultaneous recovery of energy and mineral constituents: the production of solid recovered fuels (SRFs) from mixed municipal and commercial waste and their use in the cement industry is often referred to as co-processing. The state of the art of SRF production is described and the first comprehensive dataset for SRF samples including major constituents, heavy metal and metalloid contents, energy- and CO2-emission-relevant parameters, ash constituents and the material-recyclable share of SRF is presented. Additionally, a comparison with fossil fuels is given. It is concluded that SRF from state-of-the-art production plants complies with strict limit values for heavy metals, has an average biogenic carbon content of 60%, and its application in the cement industry can be considered as partial recycling (14.5%) and partial energy recovery (85.5%). Leaving no residues to be dealt with, co-processing of waste in the cement industry therefore offers many benefits and can support the shift from a linear to a circular economy.

Design of 50KLD MBBR based Sewage Treatment for Hostel Building, Nagpur

Abstract: Sewage water recovery is the treatment or processing of Sewage water to make it applicable. This paper shows the design of various component of conventional sewage treatment plant using Moving Bed Biofilm Reactor technique at College Hostel, Nagpur. The project consisting of the design of complete Sewage Treatment Plant components consist of Bar Screen Chamber, Equalization Tank, Aeration Tank, Clarifier Tank, Pressure Sand filter, Activated Carbon Filter and Treated Water Tank. Among the available technologies for waste water treatment, MBBR sewage treatment is most suitable. It is a leading technology in waste water treatment as this system can operate at lower vestiges and give advanced efficiency of treatment. It’s compact and effective option for domestic waste treatment. In duly designed MBBR, the whole reactor volume is active, with no dead space or short circuiting. This paper demonstrates the detailed procedure for the design of a MBBR grounded sewage treatment plant of 50 KLD capacity for an educational lot.

The decomposition and emission factors of a wide range of PFAS in diverse, contaminated organic waste fractions undergoing dry pyrolysis

Current treatment options for organic waste contaminated with per- and polyfluoroalkyl substances (PFAS) are generally limited to incineration, composting or landfilling, all resulting in emissions. Dry pyrolysis is a promising emerging alternative to these practices, but there is uncertainty related to the fate of PFAS during this process. The present work first developed a robust method for the determination of PFAS in complex matrices, such as sewage sludge and biochar. Then, a mass balance was established for 56 different PFAS during full-scale pyrolysis (2–10 kg biochar hr-1, 500–800 °C) of sewage sludges, food waste reject, garden waste and waste timber. PFAS were found in all wastes (56–3651 ng g-1), but pyrolysis resulted in a ≥ 96.9% removal. Residual PFAS (0.1–3.4 ng g-1) were detected in biochars obtained at temperatures up to 750 °C and were dominated by long chain PFAS. Emitted PFAS loads ranged from 0.01 to 3.1 mg tonne-1 of biochar produced and were dominated by short chain PFAS. Emissions made up < 3% of total PFAS-mass in the wastes. Remaining uncertainties are mainly related to the presence of thermal degradation products in flue gas and condensation oils.

Utilizing animal by-products in European slaughterhouses to reduce the environmental footprint of pork products

Reducing food loss addresses global warming, protects natural resources, and improves food security. The study focuses on improving the use of animal by-products at the slaughterhouse stage.An LCA of pork production was performed using actual data from four European slaughterhouses and two methods for handling by-products. A scenario analysis was then conducted to compare the improved re-use of animal by-products.The study showed substantial variations in the proportion of live weight pig used for human food purposes, with an edible yield ranging from 72 to 88 %. Improved utilization, where 92 % of the live weight pig is used as edible products, could reduce environmental impact per kg pork product sold for human consumption by 4–26 % depending on the current utilization rate, impact category, and by-product handling method. Using system expansion, such as substituting soybean meal in pet feed, lowered the reduction potential from 19 % with economic allocation to 7 % with system expansion due to high net avoided impacts, highlighting the importance of the method to accurately evaluate the environmental benefits of utilizing more edible products. A scenario analysis comparing waste treatment options for the animal by-products proved that the best option is pet feed, followed by biofuel, then biogas, aligning with the circular bioeconomy value pyramid and food waste hierarchy.Higher edible yield per live weight pig considerably reduces the environmental impacts per kg pork product sold for human consumption. The waste hierarchy and the value pyramid are useful tools to prioritize waste utilization for animal by-products.

Set of Small Molecule Polyurethane (PU) Model Substrates: Ecotoxicity Evaluation and Identification of PU Degrading Biocatalysts

Polyurethanes (PUs) are an exceedingly heterogeneous group of plastic polymers, widely used in a variety of industries from construction to medical implants. In the past decades, we have witnessed the accumulation of PU waste and its detrimental environmental impacts. PUs have been identified as one of the most toxic polymers leaching hazardous compounds derived both from the polymer itself and the additives used in production. Further environmental impact assessment, identification and characterization of substances derived from PU materials and establishing efficient degradation strategies are crucial. Thus, a selection of eight synthetic model compounds which represent partial PU hydrolysis products were synthesized and characterized both in terms of toxicity and suitability to be used as substrates for the identification of novel biocatalysts for PU biodegradation. Overall, the compounds exhibited low in vitro cytotoxicity against a healthy human fibroblast cell line and virtually no toxic effect on the nematode Caenorhabditis elegans up to 500 µg mL−1, and two of the substrates showed moderate aquatic ecotoxicity with EC50 values 53 µg mL−1 and 45 µg mL−1, respectively, on Aliivibrio fischeri. The compounds were successfully applied to study the mechanism of ester and urethane bond cleaving preference of known plastic-degrading enzymes and were used to single out a novel PU-degrading biocatalyst, Amycolatopsis mediterranei ISP5501, among 220 microbial strains. A. mediterranei ISP5501 can also degrade commercially available polyether and polyester PU materials, reducing the average molecular number of the polymer up to 13.5%. This study uncovered a biocatalyst capable of degrading different types of PUs and identified potential enzymes responsible as a key step in developing biotechnological process for PU waste treatment options.

Life cycle assessment (LCA) on waste management options for derelict fishing gear

PurposeDerelict fishing gear (DFG) is one of the most abundant and harmful types of marine litter that gets increasingly retrieved from the ocean. However, for this novel waste stream recycling and recovery pathways are not yet commonly established. To identify the most suitable waste management system, this study assesses the potential environmental impacts of DFG waste treatment options in Europe.MethodsThis study applies an attributional life cycle assessment (LCA) to four DFG waste treatment scenarios, namely a mechanical recycling, syngas production, energy recovery and landfill disposal. The scope spans from the retrieval and transport processes to pre- and end-treatment steps until the outputs are sent to landfill or assumed to substitute products or energy. Primary data was collected from retrieval and waste treatment trials in Europe. Contribution, sensitivity and uncertainty analyses were conducted using the LCA software SimaPro and ReCiPe as the impact methodology.Results and discussionThe results show that the mechanical recycling and energy recovery achieve the lowest potential environmental impacts. The syngas production and landfill disposal scenario are not environmentally competitive because they require too much electricity, or their avoided production credits were too small to offset their emissions. Unlike the pre-treatment and transport processes, the retrieval and end-treatment processes have a significant impact on the overall results. The transport distances, energy mix and market and technological assumptions are least sensitive, while changes to the waste composition significantly affect the results. Especially a reduced lead content benefits the human toxicity impact potential of the landfill disposal scenario. The uncertainty analysis showed that the results are very robust in nine of twelve impact categories.ConclusionsThis is the first LCA study that compares waste treatment options for marine litter. The results indicate that a disposal of DFG is hazardous and should be replaced with mechanical recycling or energy recovery. While this may be technologically possible and environmentally beneficial, economic and social factors should also be considered before a final decision is made. To further reduce environmental impacts, marine litter prevention should play a more important role.Graphical abstract

Treatment of food waste contaminated by bioplastics using BSF larvae: Impact and fate of starch-based bioplastic films

The use of Black Soldier Fly (BSF) larvae in the treatment of biowaste, including food waste, represents a promising new (waste) treatment option. In line with an increasing use of starch-based bioplastics in food packaging, (e.g. shopper films), food waste contamination by these polymers is expected to rise, but the fate of these materials and impact produced on the BSF treatment process remain to be clarified. In the present study, food waste contaminated by starch-based bioplastic film was treated using a BSF larvae process with the aim of investigating both the effect of bioplastics on process performance and the effect of BSF larvae on bioplastic degradation. Larvae treatment performance was assessed by monitoring substrate degradation process and larvae growth in terms of weight variation and development time. Bioplastic degradation (both in the larvae process and in a larvae-free control test) was assessed by means of visual inspection, Scanning Electron Microscopy (SEM), Fourier Transform InfraRed spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and ThermoGravimetric Analysis (TGA). The results obtained highlighted the absence of negative impacts of bioplastics on the BSF process, revealing a modestly higher degree of degradation in the larvae process compared to control test. The process however failed to achieve complete degradation of bioplastics, suggesting the need for additional post-processing treatments.

The need for design-for-recycling of paper-based printed electronics – a prospective comparison with printed circuit boards

The present study compares conventional printed circuit boards (having glass-fibre and epoxy substrates and etched copper circuits) with paper-based printed electronics (offering flexible, bio-based, and biodegradable substrates with circuit design printed using silver-based inks) and assesses the relevance of e-waste recycling to the latter's sustainability. Therefore, a comparative life cycle assessment between these two options has been undertaken and the global warming impacts were calculated.The impact assessment results underscore that printed electronics offer a consistent sustainability advantage over printed circuit boards only through recycling of silver in the former at the end-of-life. Hence, design-for-recycling and recycling as e-waste are crucial to the sustainability of the current generation of printed electronics. Other foreseen waste treatment options for paper-based printed electronics, such as composting, and paper recycling, are likely to limit the sustainability advantage of printed electronics to circuits with small conductive areas.

Decentralized Solid Waste Management in Rural Ghana: A Case Study of Assin Kushea Community in Assin North Municipality

Management of solid waste continues to be a major developmental challenge for developing countries like Ghana. The current focus and attention have been on the collection and dumping of waste in urban communities where generation rate is high to the detriment of rural communities. In this study, a pilot waste management scheme was undertaken in Assin Kushea, a rural community in the Assin North Municipality, to determine the willingness of the community to sort their waste at source, the quantity of waste generated by the community, and the characteristics of the waste to inform the treatment or disposal options suitable for the community. The results of the study showed that the community generates approximately 20 to 40 kg waste per day which comprises about 77% biological municipal waste (BMW) and 23% of residual waste. Laboratory analysis of the waste showed that the moisture content of the waste was about 68%. The percentage volatile solid was about 85.45%, leaving an ash content of approximately 14.55% all by weight of the waste materials. More than 50% of the sampled population achieved 100% source separation efficiency. Given the composition and characteristics of the waste, and the willingness of the community to sort their waste at source, composting or anaerobic fermentation of the organic waste fraction is recommended as the best waste treatment option for the organic component of the waste for the community.

Assessment of Solid Waste Management System in Pakistan and Sustainable Model from Environmental and Economic Perspective

The Solid Waste Management (SWM) sector is given a low-priority by the Pakistani Government, with the climate change agenda of Sustainable Development Goals (SDGs) being a priority-3 only, similar to other developing countries. Although sustained efforts have been made during the last decade to strengthen the SWM sector, all actions were focused on manual sweeping and waste collection without integrating waste treatment and disposal options. In this respect, the current model of SWM in the country was analyzed for efficient future planning to strengthen the sector waste management regime in line with the targets of Nationally Determined Contributors (NDCs) and SDGs. An assessment of the SWM sector was performed in eleven major cities of Pakistan, applying Waste-aware benchmarking indicators as strategic tools. The current study highlights the strengths and weaknesses of concerned local municipalities and Waste Management Companies (WMCs) along with interventions to reduce Greenhouse Gases (GHGs) emission targets by 2030. Proposed interventions from the environment and economy perspective will generate revenue to cater for up to 29% of the operational costs, and this will be an important step towards 100% self-sufficiency in the SWM sector.

Physical and biomimetic treatment methods to reduce microplastic waste accumulation.

BackgroundSince the Covid-19 pandemic in 2019, the use of plastics has increased exponentially, so it is imperative to manage and dispose of these plastic wastes safely.ObjectivesThis review focuses on the management strategies governed by the policies of each country to reduce plastic waste through physical collection methods and methods that use eco-imitation technologies.ResultsThus far, physical treatment methods have been applied to sewage and drinking water treatment. The abilities of bio-inspired treatment methods are being assessed in terms of capturing microplastics (MPs) and nanoplastics (NPs), extracting substances from marine organisms, reducing toxicity, and developing alternatives to petroleum-based plastics.ConclusionsVarious post-treatment methods have been proposed to collect and remove MPs and NPs that have reached into aquatic ecosystems and subsequently reduce their toxicity. However, there are limitations that the effectiveness of these methods is hindered by the lack of policies governing the entire process of plastic use before the post-treatment.Purpose of ReviewWe purpose to reduce plastic waste through methods that use eco-imitation technologies.Recent FindingsThese eco-imitation methods are attracting attention as viable future plastic waste treatment options in line with the goals of sustainable development.

End-of-life treatment of EPS-based building insulation material – An estimation of future waste and review of treatment options

Expanded Polystyrene (EPS) used in External Thermal Insulation Composite Systems (ETICS) is mainly disposed of in waste incineration plants. However, alternative recycling options need to be identified as capacities for this waste treatment are limited and the amount of EPS-based ETICS waste is expected to increase. Herein, it is necessary to quantify the future waste masses with regard to regional distribution as EPS-based ETICS waste is generated decentrally. Furthermore, consistent information on alternative treatment options for EPS-based ETICS waste is lacking.First, we estimate the amount of upcoming EPS waste from ETICS in Germany with a high spatial resolution. Second, we evaluate state-of-the-art waste management options regarding economic, legal and environmental aspects. We find that waste masses will increase from 3 to 33 kt (2020-2040) with large spatial deviations. We conclude that solvent-based recycling seems promising, but more sophisticated analyses are required, i.e. planning of the future waste treatment infrastructures.