Disposal Of Biomass Research Articles

Co-pyrolysis of rubber seed oil and industrial hemp stem: Asym2sig deconvolution, thermal behavior, synergistic reaction and kinetic

Evaluation of Kinetic triplets and thermodynamics of the co-pyrolysis of industrial hemp stem (IHS) and rubber seed oil (RSO) contributes to the efficient utilization of agricultural waste. The thermodynamics and kinetics of four pseudo components from mixture (RSO: IHS=1: 1) are investigated using Asym2sig deconvolution. The results show that the Eα of pseudo hemicellulose, pseudo cellulose, pseudo triglyceride and pseudo lignin are 76.019, 193.587, 231.764 and 408.552 kJ/mol. The average differences in Eα and ΔH for the four pseudo-fractions also are 4.439, 4.929, 5.576 and 6.018 kJ/mol. Lower energy barrier favors the reaction. The frequency factor values for four pseudo-components pyrolysis are 1.07 × 108 s−1 for pseudo hemicellulose, 1.78 × 1019 s−1 for pseudo cellulose, 6.04 × 1018 s−1 for pseudo triglyceride, and 6.96 × 1031 s−1 for pseudo lignin. The four pseudo-components have different pyrolysis reaction mechanisms. The synergistic effect calculations show a significant interaction between RSO and IHS. According to thermodynamic analysis, the pyrolysis of the four pseudo components requires the provision of external energy. FT-IR results indicate that RSO can significantly increase the release of C2H2, C2H4, C2H6 and CH4 during the co-pyrolysis of RSO and IHS. The co-pyrolysis of IHS and RSO can increase the content of alkene, alkane and MAHs, which improve the quality of bio-oil significantly. Besides, it can reduce the content of PAHs, which reduces the viscosity of the bio-oil. The results can provide new insights into the synergistic and efficient disposal of triglycerides and lignocellulosic biomass.

Thermal Behaviour, Chemical Composition and Morphological analysis ofCotton Stalk for Efficient Biochar Production

The escalating concern over air pollution from crop stubble burning necessitates responsible biomass disposal or utilisation. In this study, characterisation of cotton stalk was carried out to assess its feasibility for biochar production. The proximate analysis revealed that cotton stalk had moisture content of 8.65%, bulk density of 215.8 kg m-3, volatile matter of 71.65%, and fixed carbon content of 16.03%. The ultimate analysis showed that cotton stalks were predominantly composed of carbon (64.88%), hydrogen (6.58%) , and oxygen (2.55%), with a low (0.66%) nitrogen content . Thermo-gravimetric analysis (TGA) highlighted the pyrolysis process, identifying a peak temperature of approximately 500°C and distinct stages of thermal degradation: moisture loss up to 150°C, hemicellulose decomposition between 200°C and 300°C, cellulose decomposition from 300°C to 400°C, and lignin decomposition from 400°C to 500°C. X-ray diffraction (XRD) analysis confirmed the presence of crystalline cellulose with a diffraction peak at 2θ = 22.5°, indicating significant structural stability during pyrolysis for biochar production. Fourier-transform infrared (FTIR) spectroscopy revealed characteristic peaks associated with cellulose and lignin, underscoring the retention of essential structural components in biochar during biomass conversion. These analyses demonstrated the potential of cotton stalks as a viable feedstock for biochar production, providing a sustainable method for agricultural waste management and soil health improvement.

CHARACTERIZATION OF UNBLEACHED PULP FROM EMPTY FRUIT BUNCHES OF OIL PALM AS A RAW MATERIAL FOR BROWN PAPER

Improper disposal of palm biomass wastes resulting from industrial palm oil production may contribute to the environmental issues in Indonesia. However, given their abundance and availability, empty fruit bunches (EFB) can be potentially considered as a raw material for unbleached pulp. In this study, unbleached pulp was produced from oil palm EFB by a pulping process with alkaline pretreatment. FT-IR analysis confirmed the presence of cellulose in the pulp, with absorption peaks at 3332 cm-1 corresponding to the O-H stretching and at 1029 cm-1 assigned to the stretching of the C-O-C bond, respectively. SEM images revealed the aspect of individual fibers, with a rigid appearance, in the pulp obtained from EFB biomass. The major crystalline peak was observed at 2θ of 22.41°, indicating the presence of cellulose. Brown paper was made from the unbleached pulp (A4 size, with a grammage of 134 g/m2 and a thickness of 219.3 μm) and proved to have excellent mechanical strength. Therefore, unbleached pulp from oil palm EFB can be recommended to be used in the manufacture of brown paper.

Biomass Derived Biofluorescent Carbon Dots for Energy Applications: Current Progress and Prospects.

Biomass resources are often disposed of inefficiently and it causes environmental degradation. These wastes can be turned into bio-products using effective conversion techniques. The synthesis of high-value bio-products from biomass adheres to the principles of a sustainable circular economy in a variety of industries, including agriculture. Recently, fluorescent carbon dots (C-dots) derived from biowastes have emerged as a breakthrough in the field, showcasing outstanding fluorescence properties and biocompatibility. The C-dots exhibit unique quantum confinement properties due to their small size, contributing to their exceptional fluorescence. The significance of their fluorescent properties lies in their versatile applications, particularly in bio-imaging and energy devices. Their rapid and straight-forward production using green/chemical precursors has further accelerated their adoption in diverse applications. The use of green precursors for C-dot not only addresses the biomass disposal issue through a scientific approach, but also establishes a path for a circular economy. This approach not only minimizes biowaste, which also harnesses the potential of fluorescent C-dots to contribute to sustainable practices in agriculture. This review explores recent developments and challenges in synthesizing high-quality C-dots from agro-residues, shedding light on their crucial role in advancing technologies for a cleaner and more sustainable future.

Thermochemical conversion of guaiacol with supercritical CO2: Experimental insights

The excessive CO2 in the environment resulting from the combustion of fossil fuels has posed a significant challenge in terms of its conversion and utilization. In this work, the thermochemical conversion of guaiacol under supercritical CO2 (scCO2) was proposed, which not only enabled the consumption of CO2 but also facilitated the conversion of biomass into valuable products. It was concluded that the carbon gasification efficiency (CE) and hydrogen gasification efficiency (HE) were 37.10 % and 51.77 %, respectively, when the CO reached the maximum of 8.72 ± 0.28 mol/kg at 700 °C for 20 min. The addition of catalyst promoted the production of H2 and increased CE, the H2 yield of guaiacol gasification under different catalysts was ordered as Al2O3 > KOH > without catalyst > KCl. As the reaction temperature increased, the unreacted guaiacol and phenol decreased and were gradually converted to liquid products such as pyrene and benzo[c]phenanthrene. With the increase in reaction temperature, the more fully guaiacol was reacted, the easier it was to carbonize and form more carbon microspheres. In addition, reaction pathways for free radicals were proposed, including cleavage of free radicals, isomerization of free radicals, secondary cleavage of free radicals and recombination of free radicals. In short, degrading guaiacol using scCO2 is a feasible approach, which provides a new direction for the disposal and energy recovery of biomass in the future.

ECONOMIC EFFICIENCY OF THE PRODUCTION OF BIOCHAR AND SOLID FUEL BASED ON BIOCAL

Useful disposal of industrial waste and biomass remains is increasingly relevant for Ukrainian enterprises. The purpose of this article is to find additional opportunities for the production of products with greater added value by processing waste and biomass residues to biochar. World prices for biochar are quite high, much higher than for the use of biocoals as fuel, and are around 800 EUR/t, maximum up to 1,800 EUR/t. The main technical characteristics and price offers of equipment for the production of biochar from nine manufacturers from China, Germany, Finland, Norway and the Netherlands were analyzed. The results of feasibility study of the biochar production from sunflower husks on a technological line with an input productivity of 5 t/h for one of the Ukrainian vegetable oils production plants are presented. As the main equipment, a drum-type pyrolyzer heated by synthesis gas, formed during the thermochemical decomposition of biomass, was considered. Byproducts of production are also bioacetic acid and tar oil. The financial indicators in the case of biochar export are attractive enough for implementation. The estimated simple payback period when using granulated husk was about 4 years at a price of biochar of 650 EUR/t and less than one year at a price of 800 EUR/t. When using non-granulated husk, the simple payback period was about 3 years, even at the price of biochar of 450 EUR/t. Possible risks for implementation are the uncertainty regarding market demand and sales opportunities for biochar, quality requirements and the ability of the considered equipment to provide them, insufficient information regarding biochar yield from various biomass, as well as the lack of experience. Enterprises interested in the implementation of such a project are recommended to conduct trial processing of a batch of their raw materials on similar equipment in advance, to determine the share of biochar yield and its quality characteristics, to search for potential buyers to discuss quality requirements and possible prices.

Bioleaching of Cd from contaminated Helianthus annuus L. stalk and the safe utilization of its byproducts by Aspergillus niger

Disposal and recycling of heavy metal-enriched biomass is the key to measure the success of phytoremediation. This study employed innovative approach to use Aspergillus niger (A. niger) for the treatment of Cd-contaminated Helianthus annuus L. (sunflower) stalk after phytoremediation. Single-factor results showed that the removal of Cd at an initial pH of 3 was superior to sucrose and inoculation amount. 67.67% of Cd was removed by A. niger leaching system after 11 days based on response surface methodology optimum conditions (sucrose: 76.266 g L−1; inoculation amount: 10%; initial pH: 3), while the concentrations of nitrogen, phosphorus and potassium (N, P and K) of sunflower stalk were unaffected. While physicochemical pretreatment effectively enhanced the bioleaching efficiency, it also resulted in significant loss of P and K elements, thereby reducing the value of biomass for recycling and utilization. Therefore, the direct A. niger leaching method without pretreatment is more advantageous for the safe treatment and recycling of Cd-contaminated sunflower stalks.

Biochar-based catalysts: a potential disposal of plant biomass from phytoremediation

Abstract In this study, the plant biomass from the phytoremediation was recovered, prepared, and investigated catalytic ability for the α-pinene isomerization. The results show that the Fe_loaded AAL biochar can catalyze the isomerization of a-pinene, with the α-pinene conversion of 90.5 % and the selectivities for monocyclic terpenes (limonene, terpinolene and γ-terpinene) of 57.1 %, bicyclic terpene (camphene) of 24.6 %. Iron in the plant biomass from phytoremediation is considered a decisive factor that heightened the conversion of α-pinene and the yield of isomers. This research has initially opened up a new application for the plant biomass absorbing heavy metal from the phytoremediation stage to resolve contaminants efficiently.

Assessing Environmental Sustainability of Phytoremediation to Remove Copper from Contaminated Soils

Phytoremediation stands out as a promising technology for removing heavy metals from contaminated soils. This work focuses on studying the environmental performance of phytoremediation in removing copper from contaminated soil located in an old Spanish mine using the life cycle assessment (LCA) method. For this purpose, Brassica juncea (brown mustard), Medicago sativa (alfalfa) and their rotary cultivation were assessed along with different options for managing biomass (landfill disposal and biomass cogeneration). In addition, soil excavation and soil washing treatments were also compared to phytoremediation. M. sativa proved superior to B. juncea and their rotary cultivation, regardless of the biomass disposal option, achieving impact reductions of 30–100%. This is due to the ability of M. sativa to fix nitrogen, which reduces fertiliser requirements. Among the biomass management alternatives, cogeneration was superior to landfill disposal in all cases by allowing for energy recovery, thereby reducing environmental impacts by 60–100%. M. sativa + cogeneration is the option that presents the best environmental performance of all the studied treatments, achieving reductions up to negligible values in four of eight impact categories due to the impacts avoided by energy production. On the contrary, soil excavation is the less desirable option, followed by soil washing treatment.

Analysis of Petrogenic Hydrocarbons in Plant Tissues: A Simple GC-MS-Based Protocol to Distinguish Biogenic Hydrocarbons from Diesel-Derived Compounds.

Diesel contamination of farming soils is of great concern because hydrocarbons are toxic to all forms of life and can potentially enter the food web through crops or plants used for remediation. Data on plant ability to uptake, translocate and accumulate diesel-derived compounds are controversial not only due to the probable diverse attitude of plant species but also because of the lack of a reliable method with which to distinguish petrogenic from biogenic compounds in plant tissues. The purpose of this study was to set up a GC-MS-based protocol enabling the determination of diesel-derived hydrocarbons in plants grown in contaminated soil for assessing human and ecological risks, predicting phytoremediation effectiveness and biomass disposal. To this end, two plant species, Vicia sativa L. and Secale cereale L., belonging to two diverse vascular plant families, were used as plant models. They were grown in soil spiked with increasing concentrations of diesel fuel, and the produced biomass was used to set up the hydrocarbon extraction and GC-MSD analysis. The developed protocol was also applied to the analysis of Typha latifolia L. plants, belonging to a different botanical family and grown in a long-time and highly contaminated natural soil. Results showed the possibility of distinguishing diesel-derived compounds from biogenic hydrocarbons in most terrestrial vascular plants, just considering the total diesel compounds in the n-alkanes carbon range C10-C26, where the interference of biogenic compounds is negligible. Diesel hydrocarbons quantification in plant tissues was strongly correlated (0.92 < r2 < 0.99) to the concentration of diesel in spiked soils, suggesting a general ability of the considered plant species to adsorb and translocate relatively low amounts of diesel hydrocarbons and the reliability of the developed protocol.

Green synthesis of NiO nanoparticles using a Cd hyperaccumulator (Lactuca sativa L.) and its application as a Pb(II) and Cu(II) adsorbent

The proliferation of heavy metal contamination, namely, lead and copper, has emerged as a pervasive worldwide peril to human existence. One potential solution for addressing this issue is the utilization of nanoparticle adsorption, specifically for nickel oxide nanoparticles. However, to promote environmental sustainability, scholarly studies have identified green synthesis as a prospective methodology. The process of cadmium phytoremediation, although offering a potential remedy for heavy metal contamination, gives rise to apprehensions surrounding the proper disposal of cadmium hyperaccumulator plant biomass. Hence, it is imperative to establish suitable strategies for the disposition or usage of this biomass. The utilization of hyperaccumulator extracts for the eco-friendly production of nickel oxide nanoparticles remains unexplored in the current literature. The main aim of this research is to explore the possible application of Lactuca sativa L. as a plant species with the ability to accumulate high levels of cadmium. The study also seeks to examine the efficacy of utilizing these plants in the fabrication of nickel oxide nanoparticles and evaluate their capacity to absorb lead and copper ions. The characterization of nickel oxide nanoparticles is conducted through a range of techniques, encompassing scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller spectroscopy, and vibrating sample magnetometry. The present work achieved successful utilization of Lactuca sativa L. extract for the manufacture of nickel oxide nanoparticles, which showed notable efficacy as an adsorbent for lead and copper. The synthesis of nickel oxide nanoparticles using an extract from Lactuca sativa L. has demonstrated the viability of utilizing hyperaccumulator biomass in the phytoremediation of cadmium. This finding presents a promising avenue for investigating hyperaccumulator plants as potential sources for nanoparticle synthesis in the field of environment-based nanotechnology development.

Experimental investigation of chestnut shells gasification

Fossil fuels substitution with renewable energy sources is necessary for an effective decarbonization. Biomass can represent a valid alternative to fossil fuels, reducing greenhouse gas emissions. Furthermore, bioenergy generation avoids costs and problems related to biomass disposal. This study presents the energetic valorisation of chestnut shells, a byproduct of the chestnut transformation processes. Through a thermo-conversion system based on gasification, this material was considered not as a waste, but as a resource to be exploited to produce bioenergy and biochar. The fuel gas produced through the gasification process can partially replace the LPG currently used to meet the energy required for the brulage and steam peeling processes. Experimental gasification tests were carried out to evaluate this biomass by means of a laboratory scale micro-gasifier (Imbert downdraft type). Chestnut shells were pelletized with a pelletizer machine to avoid the bridging effect inside the gasifier and increase its energy density. The fuel gas obtained was sampled and analyzed to measure its composition and HHV. In addition, the gasification efficiency was calculated obtaining a value of 70%, a result in line with the ones obtained with higher quality biomasses.

Unlocking the potential: A paradigm-shifting approach for valorizing lignocellulosic waste biomass of constructed wetland enabling environmental and societal sustainability

Constructed wetlands (CWs) are widely recognized as nature-based solutions for wastewater treatment, offering various socio-economic and ecological benefits. However, the sustainable management and disposal of waste biomass generated from CWs have received limited attention. Owing to the rich lignocellulosic proportions, the harvested vegetation can potentially serve as a feedstock for various value-added products, including natural fiber-reinforced polymeric composites (NFRPCs). In this context, for the first time, we present a comprehensive review exploring different valorization routes employed to gainfully utilize waste biomass from CWs. The study discusses various value-added products developed so far from the waste biomass of CW. Biogas generation and bioethanol production are the most commonly explored valorization pathways. However, the commercial implementation of these value-added products is stalled by factors such as growth conditions, pretreatment, moisture content, process conditions, and limited energy recovery efficiency. Furthermore, this article introduces a novel class of sustainable materials, namely NFRPCs, developed for the first time by utilizing waste biomass from CWs as a reinforcement element in the polymeric matrix. A detailed analysis of the physical, mechanical, structural, and crystallographic characteristics of Canna indica (CI)-reinforced polypropylene (PP) composites is also discussed to evaluate their pertinence for structural applications. Additionally, we provide an in-depth review of natural-fiber-reinforced polypropylene composites, comprising single-fiber composites, hybrid fiber composites, and composites reinforced with organic/inorganic fillers. This comprehensive review emphasizes the potential of utilizing waste biomass from CWs as a sustainable feedstock for developing NFRPCs. It also highlights the promising prospects of NFRPCs as a sustainable substitute to synthetic fiber-reinforced composites, contributing to a circular economy and a greener future.

Microbial Strategies for Heavy Metal Removal from Industrial Wastewater

The contamination of industrial wastewater with heavy metals poses a severe environmental and public health concern. Traditional methods of heavy metal removal often prove costly and environmentally unsustainable. In this context, microbial strategies have emerged as a promising and eco-friendly approach for effective heavy metal remediation from industrial wastewater. Microorganisms, including bacteria, fungi, and algae, have developed various mechanisms to withstand and sequester heavy metals from their surroundings. This review explores the diverse microbial strategies employed in heavy metal removal, encompassing biosorption, bioaccumulation, bioprecipitation, and bioleaching. These strategies exploit microbial cell surfaces, extracellular polymeric substances, and intracellular compartments to immobilize, transform, or release heavy metals. Moreover, recent advancements in genetic engineering and biotechnology have enabled the development of tailored microbial strains with enhanced metal-removal capabilities. The application of these engineered microbes, as well as naturally occurring strains, in bioremediation processes is discussed. This review also delves into the factors influencing microbial metal removal efficiency, such as pH, temperature, metal concentration, and co-existing contaminants. Additionally, the potential drawbacks and limitations of microbial strategies, including biomass disposal and long-term performance, are addressed. As heavy metal pollution continues to be a pressing global issue, understanding and harnessing microbial strategies for heavy metal removal from industrial wastewater holds significant promise for sustainable and cost-effective remediation practices. Integrating microbial processes into existing treatment methods can offer innovative solutions to mitigate the environmental impact of heavy metal contamination, thereby safeguarding ecosystems and public health

Optimal metal immobilization of oxygen-enriched co-combustion of Zn/Cd hyperaccumulator and textile dyeing sludge with natural or modified kaolin

Eco-friendly disposal of post-harvest and metal-enriched hyperaccumulator biomass is critical for the industrialization of phytoremediation. The addition of Al/Si-based materials, such as sludge and natural mineral additives, is intended to solve the issue of HM metal stabilization in the oxygen-enriched combustion of hyperaccumulator and slow down ash sintering. This study aimed to quantify and reveal the effects of 10% kaolin or modified kaolin on the oxygen-enriched (co-)combustions of Sedum alfredii Hance (SAH) and textile dyeing sludge (TDS) and their combustion kinetics, metal enrichment rates, and immobilization/stabilization mechanisms. The activation energies for the (co-)combustions of SAH and SAH mixed with 10% additives (ST31) were estimated at 75.84–260.97 kJ/mol and 65.58–327.59 kJ/mol, respectively. The (co-)combustion mechanism model was complex, including phase boundary, diffusion, and chemical reaction order. The co-combustion of SAH with 10% modified kaolin increased Cd and Zn immobilization by approximately 66.6% and 3.2%, respectively, compared with the theoretical data at 550 °C. The co-combustion of ST31 with 10% modified kaolin increased Cd immobilization by approximately 160.9% compared with the theoretical data at 750 °C. Obtained via thermal-acid modified treatment, modified kaolin increased the immobilization efficiencies of Zn and Cd through aluminosilicate reactions to form the stable structures (Ca–Zn–Si, Ca–Zn–Al, K–Zn–Si, Zn–Al, Zn–Si, Cd–Al, and Cd–Si) as well as physical absorption. According to the combination of the experimental, multi-objective optimization, and simulation results, SAH mixed 10% modified kaolin at 550 °C and ST31 mixed with 10% modified kaolin at 750 °C were the ideal co-combustion environment. This study can provide new insights into how to best reduce the environmental risks of the hyperaccumulator disposals through the oxygen-enriched combustion technology.

Recent Advances in Phytoremediation of Hazardous Substances using Plants: A Tool for Soil Reclamation and Sustainability

Phytoremediation techniques have emerged as a promising approach for soil reclamation and remediation of contaminated sites. This review article provides a comprehensive analysis of the different phytoremediation techniques used for soil reclamation and their effectiveness in removing contaminants from soil. The aim is to evaluate the current state of knowledge and to highlight potential avenues for future research in this field. The review begins with a discussion of the principles underlying phytoremediation, emphasizing the ability of plants to accumulate, tolerate, and detoxify contaminants through various mechanisms such as phytoaccumulation, rhizo-degradation, and rhizo-filtration. Different plant species and their suitability for phytoremediation are reviewed, considering factors such as metal tolerance, biomass production, and pollutant uptake efficiency. In addition, the role of soil amendments and their impact on improving phytoremediation efficiency is critically evaluated. Commonly used amendments, including chelating agents, organic matter, and pH adjusters, are reviewed with emphasis on their ability to increase metal bioavailability and plant uptake. The review also addresses challenges associated with phytoremediation, such as plant growth limitations, long-term sustainability, and potential risks associated with the release of pollutants into the atmosphere during biomass disposal. Strategies to mitigate these challenges, including plant breeding and genetic engineering, are discussed.

Molecular Mechanism Study of the Kinetics and Product Yields during Copyrolysis of Biomass and Solid Wastes: ReaxFF-MD Method Approach.

Copyrolysis is a potential method for the collaborative disposal of biomass and plastics. There is an interaction between biomass and plastics during copyrolysis. In this work, a combination of ReaxFF-MD simulation and experimental validation was used to investigate the pyrolysis reaction process of the biomass and plastic, observing the evolution of free radicals at the molecular level and exploring the distribution of pyrolysis products. TG-MS results show that reaction temperature ranges for cellulose and PVC are 296-400 and 267-480 °C, respectively. HCl is the main product of PVC pyrolysis, and mixing with cellulose will reduce the yield of HCl. The ReaxFF method was used to model the pyrolysis of cellulose and PVC. The modeling temperature is much higher than the real reaction temperature, which is attributed to the time scale of picoseconds of ReaxFF-MD modeling. Modeling results show that the yield of HCl of the cellulose/PVC mixture is obviously lower than that of pure PVC. When mixed with cellulose, the HCl release is largely inhibited and more chlorine elements are retained in the pyrolysis hydrocarbon fraction or solid products.

Agricultural Wastewater Treatment Using Oil Palm Waste Activated Hydrochar for Reuse in Plant Irrigation: Synthesis, Characterization, and Process Optimization

The best possible use of natural resources and the large amounts of trash produced by industrial and human activity is necessary for sustainable development. Due to the threat of global climate change and other environmental challenges, waste management systems are changing, leading to more instances of water resource management. The waste generated must be controlled from a sustainability point of view. Typically, the conventional disposal of Agricultural Wastewater (AW) and biomass can be achieved by recycling, reusing, and converting them into a variety of green products. To improve the AW quality for the purposes of environmental sustainability, Sustainable Development Goals (SDGs) 6 and 14, dealing with clean water, sanitation, and life below water, are very important goals. Therefore, the present investigation evaluates the effectiveness of a Bench-scale Activated Sludge Reactor (BASR) system for AW treatment. The BASR was designed to focus on getting the maximum possible utilization out of a biosorbent derived from oil palm waste activated hydrochar (OPAH). This is in accordance with SDG 9, which targets inorganic and organic waste utilization for added value. An experiment was developed using the Response Surface Methodology (RSM). A Hydraulic Retention Time (HRT) of 1–3 days was used in the bioreactor’s setup and operation, and Mixed Liquor Suspended Solids (MLSS) concentrations of 4000–6000 mg/L were used. BASR was fed with AW with initial mean concentrations of 4486 ± 5.63 mg/L and 6649 ± 3.48 for the five-day Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) experiments, respectively. The results obtained showed that maximum reductions of 84.66% and 72.07% were recorded for BOD5 and COD, respectively. Through RSM optimization, the greatest reductions in the amounts of organic materials were achieved with a 2-day HRT and an MLSS dosage of 5000 mg/L. Substrate elimination thresholds were assessed using the first-order, the Grau second-order, and the modified Stover–Kincannon models. The reported observations were found to be perfectly fit by the modified Stover–Kincannon model, with high R2 values of 0.9908 and 0.9931 for BOD5 and COD, respectively. As a result, the model may be used to design the BASR system and forecast how the reactor would behave. The findings from this study suggest that the developed OPAH has promising potential to be applied as eco-friendly material for the removal of BOD5 and COD from AW. Consequently, the study findings additionally possess the ability to address SDGs 6, 9, and 14, in order to fulfil the United Nations (UN) goals through 2030.

Valorization of food wastes with a sequential two-step process for microbial β-carotene production: A zero waste approach

Here, two consecutive β-carotene fermentation processes were carried out with Rhodotorula glutinis yeast in the growth media obtained from orange and grape wastes. Firstly, waste biomasses were subjected to hot water extraction. Effects of waste type, drying pretreatment, particle size and solid/liquid ratio on the total concentration and yield of sugars recovered were tested. The highest sugar concentration was obtained by the hot water extraction of fresh grape pomace as 61.2 g total reducing sugars (TRS)/L at a solid/liquid ratio of 100 g/L. In the first fermentation process, effect of solid/liquid ratio (initial TRS concentration) on β-carotene production pattern of R. glutinis was investigated in the media obtained directly by hot water extraction of the wastes. Microorganism and β-carotene concentrations increased with increasing solid/liquid ratio (range 10–100 g/L), and the microbial growth data fit the Monod model well for all cases. Maximum β-carotene concentration in the growth medium obtained from hot water extraction of 100 g/L of grape pomace was determined as 5988.6 mg/L. In the second fermentation process, β-carotene was produced in the acid hydrolysate of extraction residues. 10.1 g/L and 6.7 g/L of TRS was obtained after acid hydrolysis of orange and grape residues, respectively, and the highest β-carotene concentration of 370.0 mg/L was found in the medium of hydrolyzed orange peel extraction residue. Total β-carotene production increased to 1777.1 and 3279.6 mg/L (26% and 4.9% of increase) after the second fermentation step. 85.3% and 80.2% of reduction in orange and grape waste weights were observed at the end of the process, which was an indicator of efficient waste biomass disposal. Two sequential β-carotene fermentation steps offered significant advantages in terms of both efficiency and a zero waste approach.

Machine-learning-aided thermochemical treatment of biomass: a review

Thermochemical treatment is a promising technique for biomass disposal and valorization. Recently, machine learning (ML) has been extensively used to predict yields, compositions, and properties of biochar, bio-oil, syngas, and aqueous phases produced by the thermochemical treatment of biomass. ML demonstrates great potential to aid the development of thermochemical processes. The present review aims to 1) introduce the ML schemes and strategies as well as descriptors of the input and output features in thermochemical processes; 2) summarize and compare the up-to-date research in both ML-aided wet (hydrothermal carbonization/liquefaction/gasification) and dry (torrefaction/pyrolysis/gasification) thermochemical treatment of biomass (i.e., predicting the yields, compositions, and properties of oil/char/gas/aqueous phases as well as thermal conversion behavior or kinetics); and 3) identify the gaps and provide guidance for future studies concerning how to improve predictive performance, increase generalizability, aid mechanistic and application studies, and effectively share data and models in the community. The development of biomass thermochemical treatment processes is envisaged to be greatly accelerated by ML in the near future.