Amount Of Waste Research Articles

Utilizing Geological and Geoelectrical methods in a GIS-based DRASTIC model of the Probable Groundwater Vulnerability in the Southern Nigerian Raffia Metropolis of Ikot Ekpene and its Surroundings

The city of Ikot Ekpene is facing a significant issue with groundwater contamination. This is due to the rising amount of home and industrial waste caused by the increasing human population and various business operations in the area. This study seeks to evaluate the susceptibility of groundwater in the metropolis of Ikot Ekpene and its surrounding areas in southern Nigeria. It will utilize integrated geoelectrical and geological approaches within the GIS-based DRASTIC model. A total of twenty vertical electrical soundings (VES) were conducted in the region using the Schlumberger array. Based on the geological drilling data, the interpretation of the VES data suggests that the area consists of 3-4 geoelectric layers. The lithological succession in the area exhibits a range of sediment types, including fine and coarse sand as well as gravelly sands. Additionally, there are localized occurrences of clay intercalations. The third geoelectric layer, located at a depth of 9.0–86.6 m, is the primary aquifer that can be utilized in the region. The DRASTIC model included seven environmental parameters, including depth to the water table, net recharge, aquifer medium, topography, impact of vadose zone, and hydraulic conductivity, with the purpose of conducting a vulnerability assessment. The assessment of groundwater vulnerability ratings (GVR) reveals that 75% of the research region is classified as high vulnerability, 20% as moderate vulnerability, and the remaining 5% as low vulnerability. The studied area is predominantly characterized by moderate to high Groundwater Vulnerability Rating (GVR), which is likely attributed to the generally gentle topography and the presence of highly permeable geomaterials in the upper levels of the water table.

Phase development of lime-based plasters blended with waste calcined shale

AbstractRestoration of historical buildings requires an application of suitable and convenient materials which are compatible with historical legacy. On the other hand, the used materials have to show adequate durability and fulfil current tendencies of environmental-friendliness policy. Most historical buildings have their facades made of lime-based, or more precisely, blended-lime-based plasters. Metakaolin belongs to one of the most common representatives of pozzolanic admixtures used in this field. It is an artificial product, which arises by the calcination of kaolinitic clay or claystone at temperatures of about 550–900 °C. Like every other production process, a remarkable amount of waste rises also in the case of metakaolin. This study is aimed at the utilization of this waste, specifically the waste calcined shale (WCS). It is composed of not properly burned particles with varying compositions. Contrary to metakaolin, it contains a lower amount of amorphous phase and a higher amount of kaolinite and mullite. WCS was used in the production of lime-based plasters with a dosage of up to 50%. During the hardening, the carbonation process takes place in combination with the pozzolanic reactions. It gives rise to a higher amount of amorphous structures, about 15% in the case of pure lime contrary to up to 45% (in the highest dosage of WCS) and other crystal phases such as calcium-aluminate-carbonate hydrates. Obtained phase analyses are supported by the determination of SEM analysis and mechanical properties, which are also measured depending on time.

Occurrence of recreational water quality monitoring general fecal indicator bacteria and fecal source identification genetic markers in gray seal scat

The number of gray seals (Halichoerus grypus) observed along the United States Northwest Atlantic region has been increasing for decades. These colonial animals often haul-out on beaches seasonally in numbers ranging from a few individuals to several thousands. While these larger aggregations are an important part of gray seal behavior, there is public concern that haul-outs could lead to large amounts of fecal waste in recreational areas, potentially resulting in beach closures. Yet, data to confirm whether these animals contribute to beach closures is lacking and minimal information is available on the occurrence of key water quality monitoring genetic markers in gray seal scat. This study evaluates the concentration of E. coli (EC23S857), enterococci (Entero1a), and fecal Bacteroidetes (GenBac3) as well as six fecal source identification genetic markers (HF183/BacR287, HumM2, CPQ_056, Rum2Bac, DG3, and GFD) measured by qPCR in 48 wild gray seal scat samples collected from two haul-out areas in Cape Cod (Massachusetts, U.S.A.). Findings indicate that FIB genetic markers are shed in gray seal scat at significantly different concentrations with the Entero1a genetic marker exhibiting the lowest average concentration (−0.73 log10 estimated mean copies per nanogram of DNA). In addition, systematic testing of scat samples demonstrated that qPCR assays targeting host-associated genetic markers indicative of human, ruminant, and canine fecal pollution sources remain highly specific in waters frequented by gray seals (>97 % specificity).

Enhanced H2 Generation via Piezoelectric Reforming of Waste Sugars and Fruits Using Au-Decorated g-C3N4

The food industry is responsible for generating considerable amounts of waste, such as excess fruits and leftover sugars, which contribute to resource depletion and pose environmental challenges. This research delves into the application of gold-modified graphitic carbon nitride nanosheets (Au/CN) as a potent catalyst for the transformation of these food wastes into H2 via piezoelectric reforming during sonication. Au/CN demonstrated a superior rate of H2 evolution compared to pristine g-C3N4 (i.e., 1533.3 vs. 364.9 µmol/g/h) and it maintained its efficiency through multiple cycles of use. The catalytic activity was found to be optimal at a neutral pH level and with increased sugar concentrations. The enhanced catalytic performance of Au/CN was ascribed to the efficient segregation of charge carriers as well as the reduced charge transfer distance. This study underscores the viability of using Au/CN as a means for converting food wastes into a sustainable source of H2 energy.

Environmental impacts and performance assessment of recycled fine aggregate concrete.

Natural disasters and human demolition create vast amounts of construction and demolition waste (CDW), with a substantial portion being concrete waste. Managing this concrete waste is a daunting challenge for developing countries with limited resources, aiming to mitigate its harmful environmental effects. Therefore, the proposed approach involves using recycled fine aggregates (RFA) instead of fresh fine aggregates (FFA) in concrete, which aligns closely with achieving sustainable environmental objectives. Extensive laboratory tests were conducted to assess the effects of adding RFA to concrete. The influence of 0 to 100% RFA replacement and different curing times was investigated on compressive strength, tensile strength, resistance against chloride ion penetration and chemicals exposure, and quality of aggregates. So, around 30%, 35%, 20%, and 79% reductions in compression strength, tensile strength, modulus of elasticity, and workability were estimated when 100% RFA was used in recycled aggregate concrete (RAC). However, according to results analyses, the performance of RAC is reliable up to 50% of RFA in proposed conditions and mix design. In addition, major environmental impacts such as global warming potential, aquatic eutrophication, and aquatic acidification were reduced by 47%, 40%, and 18%, respectively, for concrete having 50% RFA than concrete having 100% FFA.

Waste consumption of bio-degradable products through a secondary supply chain

Food and agriculture organization estimates that 33% of the food is wasted in the world. It is essential to optimize the food supply chains to mitigate the economic and environmental impacts of this large amount of food waste. The targets of food waste reduction can be achieved by increasing lifetime and consuming the inevitably produced food waste for producing secondary products. This research proposes a primary and secondary supply chain model, where effective preservation policy increases lifetime of food items, and the yet produced food waste is converted into secondary products. This way, the waste from the system is removed and it is converted into a sustainable zero-waste system. A nonlinear mathematical model is proposed to set the objective function of the research, which best determines the production plan, inventory schedule and investment in preservation technology while maximizing profit. The model is solved using the Kuhn-Tucker method, and the model optimality is obtained by proposing an algorithm. Numerical analysis is carried out to validate the presented model, and sensitivity analysis is performed to demonstrate the effects of variation in cost parameters on the profit. The outcome of the analysis shows that the proposed secondary supply chain increases profit by 35% and the preservation policy increases the profit by 17.9%. Besides, the proposed policies minimize and remove the food waste from system. Managerial implications are provided for the practitioners to apply the proposed model in food supply chains.

Optimization of Extraction Solvents on the Antioxidant Properties of Coconut Waste

Cocos nucifera L. (family Arecaceae) commonly known as coconut is considered as an important fruit crop in tropical countries and are widely used for therapeutic and domestic purpose. They have effective properties such as antioxidant, antitumor, antiseptic and antimicrobial. The growing demand for green coconut water consumption and food industries cause the dumping of the shell and husk of this fruit, generating large amount of solid waste. This study utilized part of coconut waste to study the impacts of solvent type on the phenolic content. Six different polarities of solvent were chosen. Total phenolic content was performed using Folin-Ciocalteu assay and free radical scavenging activity with 2,2-diphenyl-1-picrilhydrazil (DPPH) method. Total phenolic content for coconut shell was the highest at 71.57 ± 0.275 mg GAE/g for propanol extract and 74.10 ± 0.741 mg GAE/g for acetone extract of coconut husk. The antioxidant activity of all sample extracts was analysed using DPPH assay. Highest radical scavenging activity of coconut husk was observed by propanol extract with 93.82 ± 0.052 % while the lowest scavenging activity was demonstrated by chloroform extract with percentage of 57.77 ± 2.255%. Acetone extract of the shell exhibited the highest scavenging activity of 91.23 ± 0.073%, while chloroform extract of coconut shell demonstrated the lowest antioxidant activity of 70.627 ± 0.467%.

END-OF-LIFE PHOTOVOLTAIC MODULES: LIFE CYCLE ASSESSMENT AND SENSIBILITY ANALYSIS

The use of photovoltaic (PV) systems in energy generation has been grown worldwide. In Brazil, this continuous growth is seen in the increase in the number of consumer units. The expected useful life of PV modules is estimated to be between 25 and 30 years. Therefore, most of these units will be deinstalled in the near future. It is important to evaluate the environmental impacts of the technology in order to safely adopt the use of PV energy. The environmental impact of PV modules is a widely studied topic, often using life cycle analysis (LCA). However, these studies emphasize the production phase and exclude or fail to analyze in detail the uninstallation and disposal phase of PV modules. The use of precious metals and components that contain materials classified as hazardous waste has sparked recent interest in highlighting the impacts and likely benefits related to the end-of-life management of PV modules. In this context, the purpose of work is to analyze the environmental impacts of the phase of uninstallation and disposal of photovoltaic (PV) system for Brazil waste management technologies: Recycling, incineration and landfill. The life cycle assessment (LCA) was applied in three scenarios for disposal of modules: Recycling, incineration and landfill. ReCiPe 2008 method was useful to calculating the environmental impacts, with assistance of SimaPro 8.3 software. The results showed that the recycling scenario had a lower environmental performance compared to the other scenarios. The main cause is the high consumption of electricity in metal recovery stage. Besides, this scenario produces a high amount of waste (residual liquid and sludge). The scenario of recycling will be attractive with technological investment in energy efficiency. The advantage of this scenario is the material recovery (precious metal and materials classified as hazardous waste), as consequence will bring environmental benefits.

Concrete mixtures with photovoltaic panels glass: a review of the situation in Czech Republic

Solar energy production was initiated in the 1990s following by rapid increase of the use of photovoltaic (PV) technology. Most of older solar panels in the Czech Republic were installed between 2000 and 2006 and a global installed capacity of 222 GW was reached by the end of 2015. With the growing global PV market, a large amount of waste is expected to accumulate after 2030 which is associated with the new industry to process this waste, based on reduce, reuse, and recycle. This article summarizes findings and research conclusions regarding local issues collected by experts from the Czech Republic. Previous research showed that waste glass from photovoltaic panels can be used as a pozzolanic material in high-performance concrete, improving its properties. Further research on the use of waste from photovoltaic panels has been conducted in the Czech Republic since 2019 and the conclusions from various research confirm the suitability of using PV panel glass.

Effect of various geopolymerization parameters on poor quality Afşin-Elbistan fly ash-based geopolymer concretes with ground granulated blast furnace slag

The utilization of Afşin-Elbistan fly ash (FA), which cannot be used in cement and concrete industry in production of geopolymers, has been studied with some preliminary trials. In this study, FA of Afşin-Elbistan thermal power plant, which does not fit any of FA classes according to ASTM C 618, was used as a geopolymer binder raw material. The main motivation of the study is to investigate the partial usability of this type of FA, which is not sufficient on its own and creates a large amount of waste, as a geopolymer raw material. FA was replaced with ground granulated blast furnace slag (GGBFS) by the ratios of 25% and 50% (by weights) in order to develop the properties of geopolymer concrete. Sodium silicate (SS) and sodium hydroxide (SH) (10 and 14 M) were used as activators. Three different activator to binder ratios (0.45, 0.55 and 0.65) and three SS/SH ratios (0.75, 1.0 and 1.5) were chosen. Unit weight, compressive strength, splitting tensile strength, and ultrasonic pulse velocity tests were performed for 28 and 60 days. In order to investigate the microstructure, scanning electron microscopy (SEM) analyses were performed. As a result, GGBFS incorporation enhanced the properties of Afşin-Elbistan FA-based geopolymer concrete. With the increase of GGBFS content, the compressive strength values increased. The highest strengths were obtained from 50% GGBFS groups. The results revealed that Afşin-Elbistan FA (AEFA), which has the highest waste reserve among the thermal power plant fly ashes in Turkey, could be evaluated as partial geopolymer raw material.Graphical abstract

Evaluating the Effects of Metallic Waste on the Structural and Gamma-Ray Shielding Properties of Epoxy Composites.

The objective of the research is to develop novel materials that are both inexpensive and have a low density, while also being able to endure the transportation of γ-photons with low-to-medium energy levels. The outcome consisted of four epoxy resins that were strengthened with different quantities of heavy metallic waste. The density of the formed composites improved from 1.134 ± 0.022 g/cm3 to 1.560 ± 0.0312 g/cm3 when the waste content was raised from 0 to 40 weight percent. The theoretical investigation was determined using Monte Carlo (MCNP) simulation software, and the results of linear attenuation coefficient were justified experimentally in a low and medium energy range of 15-662 keV. The mass attenuation coefficient results in a low gamma energy range (15-122 keV) varied in between 3.175 and 0.159 cm2/g (for E-MW0 composite) and in between 8.212 and 0.164 cm2/g (for E-MW40 composite). The decrease in mass attenuation coefficient was detected in a medium gamma photon energy range (122-662 keV) with 0.123-0.082 cm2/g (for E-MW0 composite) and 0.121-0.080 cm2/g (for E-MW40 composite). The density of the enhanced composites influenced these parameters. As the metallic waste composition increased, the fabricated composites' half-value thickness decreased. At 15 keV, the half-value thickness decreased from 0.19 to 0.05 cm. At 59 keV, it fell from 2.70 to 1.41 cm. At 122 keV, it fell from 3.90 to 2.72 cm. At 662 keV, it fell from 7.45 to 5.56 cm. This decrease occurred as the heavy metal waste concentration increased from 0 to 40 wt.%. The study indicates that as metallic waste concentrations rise, there is a rise in the effective atomic number and a decline in the buildup factors.

Upcycling of SARS-CoV-2 Rapid Antigen Test Cassettes into Flame Retardant Plastics.

The COVID-19 pandemic resulted in the generation of large quantities of medical waste and highlighted the importance of efficient waste management systems. One good example of this is rapid antigen tests, which contain valuable resources, and which are usually incinerated after their use. The present study aimed to evaluate the potential of waste rapid antigen test cassettes (RATCs) as a resource for the preparation of sustainable flame-retardant plastics. Milled RATCs were compounded with different concentrations (10-30 wt.%) of aluminium diethylphosphinate (ADP) and injection moulded into test specimens. Prepared samples were exposed to ultraviolet (UV) ageing for varying durations and characterised by Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), tensile tests, Charpy impact tests, and vertical burning tests. FT-IR analysis revealed that RATCs are composed mainly of high-impact polystyrene (HIPS), which was further confirmed by suitable glass transition temperatures (Tg) determined by DSC and DMA. The addition of ADP resulted in progressive embrittlement of HIPS with increasing concentration, while flammability decreased significantly and reached V-1 classification at loading of 30 wt.%. UV ageing caused photo-oxidative degradation of HIPS, which resulted in decreased strain-at-break, while flammability was not affected.

Design and Study of Simple Biogas Reactor using Kitchen Waste Within the Habitat of Federal Polytechnic of Oil and Gas Bonny Island, Rivers State, Nigeria

This research work is about design and study of simple biogas reactor using Kitchen Waste within the habitat of Federal Polytechnic of Oil and Gas Bonny Island, Rivers State, Nigeria to produce gas. The objective of the work is to collect and measure the amount of waste that is been generated within the study area as well as to construct a simple laboratory scale biogas reactor and using the kitchen waste as substrate and measure the amount of gas that is been generated from biogas reactor per day. Based on the objective for this research a biogas digester was designed. Two experiments was carried out to determine the extent of production of biogas and the duration required so as to determine the rate of formation of biogas. In experiment one, dissimilar kinds of biomass like rice, potato, green leaves, sugar in different amounts were mixed with cow dung and rice husk to prepare 4 samples to determine the maximum generation of biogas through fermentation process. The gas is collected in balloons and they were measured to determine the amount of gas produced in each sample. The extent to which the blowing of balloons took place determined the quantity of gas evolved in each of the incumbent samples. In experiment two, we have used two 5lt. bottles in which the amount of cow dung used varies while same amount of kitchen waste mixture was utilized. The process and conditions for trapping and analyzing the gas is the same as in experiment one. From this experiment the rapidness of formation of biogas was observed. The experimental analysis carried out also gives us a clear idea of the indulgence of materials with respect to their combination to deferring extent of concentration to deliver optimum generation of biogas, in particular methane thereby unveiling us to develop an imminent and high performance derivative affordable biogas reactor.

Efficient IoT-Assisted Waste Collection for Urban Smart Cities.

Waste management is one of the many major challenges faced by all urban cities around the world. With the increase in population, the current mechanisms for waste collection and disposal are under strain. The waste management problem is a global challenge that requires a collaborative effort from different stakeholders. Moreover, there is a need to develop technology-based solutions besides engaging the communities and establishing novel policies. While there are several challenges in waste management, the collection of waste using the current infrastructure is among the top challenges. Waste management suffers from issues such as a limited number of collection trucks, different types of household and industrial waste, and a low number of dumping points. The focus of this paper is on utilizing the available waste collection transportation capacity to efficiently dispose of the waste in a time-efficient manner while maximizing toxic waste disposal. A novel knapsack-based technique is proposed that fills the collection trucks with waste bins from different geographic locations by taking into account the amount of waste and toxicity in the bins using IoT sensors. Using the Knapsack technique, the collection trucks are loaded with waste bins up to their carrying capacity while maximizing their toxicity. The proposed model was implemented in MATLAB, and detailed simulation results show that the proposed technique outperforms other waste collection approaches. In particular, the amount of high-priority toxic waste collection was improved up to 47% using the proposed technique. Furthermore, the number of waste collection visits is reduced in the proposed scheme as compared to the conventional method, resulting in the recovery of the equipment cost in less than a year.

Insights into Grain Milling and Fractionation Practices for Improved Food Sustainability with Emphasis on Wheat and Peas.

Cereal grains and pulses are staple foods worldwide, being the primary supply of energy, protein, and fiber in human diets. The current practice of milling and fractionation yields large quantities of byproducts and waste, which are largely downgraded and end up as animal feeds or fertilizers. This adversely affects food security and the environment, and definitely implies an urgent need for a sustainable grain processing system to rectify the current issues, particularly the management of waste and excessive use of water and energy. The current review intends to discuss the limitations and flaws of the existing practice of grain milling and fractionation, along with potential solutions to make it more sustainable, with an emphasis on wheat and peas as common fractionation crops. This review discusses a proposed sustainable grain processing system for the fractionation of wheat or peas into flour, protein, starch, and value-added components. The proposed system is a hybrid model that combines dry and wet fractionation processes in conjunction with the implementation of three principles, namely, integration, recycling, and upcycling, to improve component separation efficiency and value addition and minimize grain milling waste. The three principles are critical in making grain processing more efficient in terms of the management of waste and resources. Overall, this review provides potential solutions for how to make the grain processing system more sustainable.

Tritium Content Determination in Titanium Tritide Targets from Romanian Decommissioned Nuclear Facilities

The decommissioning or refurbishing processes of nuclear facilities result in significant amounts of radioactive wastes. Radiological characterization is essential to ensure safe handling, transportation, and disposal of these wastes and includes the assessment of the radioactivity levels and types of radioactive materials present in the wastes. The present paper presents the tritium activity determination in used titanium tritide targets from different decommissioned nuclear facilities from Măgurele Area – Romania. The determination of tritium content in tritiated targets involves the use of the Total Combustion technique coupled with Liquid Scintillation Counting analysis of the resulting tritiated water. The tritiated testosterone controlled contaminated titanium powder was used to determine the overall yield of the Total Combustion facility. The determined yields were then used to correct the experimental values obtained during the process.

The Impact of Suspension Fertilizers Based on Waste Phosphorus Salts from Polyol Production on the Yield of Maize Intended for Green Fodder

The need to import phosphorus raw materials for fertilizer purposes in Europe as well as the need to manage increasing amounts of waste contributed to the search for alternative sources of phosphorus. One of these is waste sodium–potassium phosphate from the production of polyols. Additionally, a current problem is providing an adequate amount of food, where fertilizers play the main role. Due to the increase in meat consumption, the attractiveness of growing corn for feed is increasing due to its high yield potential and rich composition. The article presents the impact of suspension fertilizers based on waste from the production of polyols on the yield of corn intended for green fodder. In a 3-year field study, the effects of a waste phosphorus source were compared with a commercial granulated phosphorus fertilizer—fosdar. In addition, the suspension fertilizers were assessed according to their composition by testing fertilizers containing only basic nutrients (NPK) and ones enriched with secondary ingredients (S and Mg) and microelements (Zn, Mn and B). The research confirmed the effectiveness of the tested suspension fertilizers. Although the yield obtained was lower than in the case of fosdar fertilization, it still remained at a high level of over 70 t∙ha−1 of fresh yield.

Forecasting municipal solid plastic waste generation and management policy using system dynamics: a case study of Khulna City in Bangladesh

A comprehensive analysis of municipal solid plastic waste (MSPW) management while emphasizing plastic pollution severity in coastal cities around the world is mandatory to alleviate the augmenting plastic waste footprint in nature. Thus, decision-makers’ persuasion for numerous management solutions of MSPW flow-control can be met through meditative systematic strategies at the regional level. To forecast solutions focused on systematic policies, an agent-based system dynamics (ASD) model has been developed and simulated from 2023 to 2040 while considering significant knit parameters for MSPW management of Khulna City in Bangladesh. Baseline simulation results show that per-capita plastic waste generation will increase to 11.6 kg by 2040 from 8.92 kg in 2023. Eventually, the landfilled quantity of plastic waste has accumulated to 70,000 tons within 18 years. Moreover, the riverine discharge has increased to 834 tons in 2040 from a baseline quantity of 512 tons in 2023. So the plastic waste footprint index (PWFI) value rises to 24 by 2040. Furthermore, the absence of technological initiatives is responsible for the logarithmic rise of non-recyclable plastic waste to 1.35*1000=1350 tons. Finally, two consecutive policy scenarios with baseline factors such as controlled riverine discharge, increased collection and separation of plastic waste, expansion of recycle business, and locally achievable plastic conversion technologies have been simulated. Therefore, policy 2, with 69% conversion, 80% source separation, and 50% riverine discharge reduction of MSPW, has been found adequate from a sustainability perspective with the lowest PWFI ranges of 3.97 to 1.07 alongside a per-capita MSPW generation of 7.63 to 10 kg from 2023 till 2040.Graphical abstract

GARBAGE COLLECTOR USING ARDUINO

The amount of Solid waste that is being produced through our everyday activities is huge and is getting unmanageable day by day. This is mainly due to increasing population leading to haphazard dumping and increasing transportation costs with already few cost-effective methods to treat the solid waste. According to an estimate in 2016, 277 million tons of solid waste is produced by India every year. It is also projected to increase to 387 million tons by 2030 and 543 million tons by 2050. The very first method involved in the Solid Waste Management is sorting of waste which simplifies the further procedure as to what to do with the waste i.e., should it be treated thermally, biologically or dumped. Improper segregation of solid waste and segregation at secondary levels of waste management is only going to delay the waste management process and sometimes even lead to inappropriate dumping. This project suggests a way to deal with segregation process so as to make the whole solid waste management easier and more efficient. Automatic Waste Segregation system provides a practical segregation process of solid waste into metal waste, dry waste and wet waste at the primary level right where the waste is being generated. An Automatic Waste Segregator with simpler mechanism than that of previous models is designed and a detailed methodology of the working of the segregation process is provided. Selection of the required equipment has been mentioned. This project aims at segregating the waste produced at the primary level and reducing the burden at secondary levels and cost of transportation of the waste. The results obtained after testing the Automatic Waste Segregator with wastes proved to be functional and can be comfortably relied upon to segregate the wastes.

Comparative Study of Microwave, Pulsed Electric Fields, and High Pressure Processing on the Extraction of Antioxidants from Olive Pomace.

Olive oil production is characterized by large amounts of waste, and yet is considerably highly valued. Olive pomace can serve as a cheap source of bioactive compounds (BACs) with important antioxidant activity. Novel technologies like Pulsed Electric Fields (PEF) and High Pressure (HP) and microwave (MW) processing are considered green alternatives for the recovery of BACs. Different microwave (150-600 W), PEF (1-5 kV/cm field strength, 100-1500 pulses/15 µs width), and HP (250-650 MPa) conditions, in various product/solvent ratios, methanol concentrations, extraction temperatures, and processing times were investigated. Results indicated that the optimal MW extraction conditions were 300 W at 50 °C for 5 min using 60% v/v methanol with a product/solvent ratio of 1:10 g/mL. Similarly, the mix of 40% v/v methanol with olive pomace, treated at 650 MPa for the time needed for pressure build-up (1 min) were considered as optimal extraction conditions in the case of HP, while for PEF the optimal conditions were 60% v/v methanol with a product/solvent ratio of 1:10 g/mL, treated at 5000 pulses, followed by 1 h extraction under stirring conditions. Therefore, these alternative extraction technologies could assist the conventional practice in minimizing waste production and simultaneously align with the requirements of the circular bioeconomy concept.