Biomass Waste Streams Research Articles

Relevant biochar characteristics influencing compressive strength of biochar-cement mortars

To counteract the contribution of CO2 emissions by cement production and utilization, biochar is being harnessed as a carbon-negative additive in concrete. Increasing the cement replacement and biochar dosage will increase the carbon offset, but there is large variability in methods being used and many researchers report strength decreases at cement replacements beyond 5%. This work presents a reliable method to replace 10% of the cement mass with a vast selection of biochars without decreasing ultimate compressive strength, and in many cases significantly improving it. By carefully quantifying the physical and chemical properties of each biochar used, machine learning algorithms were used to elucidate the three most influential biochar characteristics that control mortar strength: initial saturation percentage, oxygen-to-carbon ratio, and soluble silicon. These results provide additional research avenues for utilizing several potential biomass waste streams to increase the biochar dosage in cement mixes without decreasing mechanical properties.Graphical

3D Printing with Bamboo: An Early-Stage Exploration towards Its Use in the Built Environment

Along with the circular bioeconomy principles, alternative ways of utilizing biomass waste streams are considered viable approaches to reaching sustainability goals. Accordingly, a growing body of literature is exploring new materials utilizing biomass in 3D-printing applications. This article presents early-stage research that initially investigates the usability of bamboo fibers and dust with bio-based binders in 3D printing towards its use in the design and production of the built environments. The research delves into solutions through a material tinkering approach to develop a bio-based composite material that can be used in fused deposition modeling (FDM). It includes mechanical strength analyses of printed specimens to understand the effects of different infill designs on the structural performance of objects printed using bamboo-based composite. Then, it demonstrates a design-to-production workflow that integrates a mechanically informed infill pattern within a self-supporting wall design that can be produced by 3D printing with bamboo. The workflow is presented with a partial demonstrator produced through robotic 3D printing. The article concludes with discussions and recommendations for further research.

Proton Exchange Membranes from Sulfonated Lignin Nanocomposites for Redox Flow Battery Applications.

Redox flow batteries (RFBs) are increasingly being considered for a wide range of energy storage applications, and such devices rely on proton exchange membranes (PEMs) to function. PEMs are high-cost, petroleum-derived polymers that often possess limited durability, variable electrochemical performance, and are linked to discharge of perfluorinated compounds. Alternative PEMs that utilize biobased materials, including lignin and sulfonated lignin (SL), low-cost byproducts of the wood pulping process, have struggled to balance electrochemical performance with dimensional stability. Herein, SL nanoparticles are demonstrated for use as a nature-derived, ion-conducting PEM material. SL nanoparticles (NanoSLs) can be synthesized for increased surface area, uniformity, and miscibility compared with macrosized lignin, improving proton conductivity. After addition of polyvinyl alcohol (PVOH) as a structural backbone, membranes with the highest NanoSL concentration demonstrated an ion exchange capacity of 1.26 meqg-1, above that of the commercial PEM Nafion 112 (0.98 meqg-1), along with a conductivity of 80.4 mScm-1 in situ, above that of many biocomposite PEMs, and a coulombic efficiency (CE), energy efficiency (EE) and voltage efficiency (VE) of 91%, 68% and 78%, respectively at 20mAcm-2. These nanocomposite PEMs demonstrate the potential for valorization of forest biomass waste streams for high value clean energy applications.

Process evaluation of mild hydrothermal carbonization to convert wet biomass residue streams into intermediate bioenergy carriers

Hydrothermal carbonization (HTC) is a promising process for the upgrading of wet biomass residues. Models of HTC processes, in particular at continuous pilot-scale, are needed to move HTC from lab-scale to industrial scale. This study presents a process model for mild HTC, dewatering and conversion to intermediate energy carriers (bio-pellets and biogas for power and/or heat production) of three wet biomass residue streams: paper sludge, olive pomace and orange peels, based on lab- and pilot-scale experiments. In addition, the process energy efficiency and feedstock utilization of the HTC process is calculated and compared with conventional treatment options for the chosen residues, i.e., direct anaerobic digestion (olive pomace, orange peels) or combustion after conventional dewatering (paper sludge). The process model indicates that the HTC pilot-scale process is much more efficient in terms of feedstock utilization to produce heat and/or power than the reference scenarios. The process energy efficiency of the HTC process (pilot-scale) was calculated to be 26 %, 63 % and 40 % for paper sludge, olive pomace and orange peel feedstocks, respectively. For all feedstocks, both the solid and liquid-generated products are equally important for improving the overall process energy efficiency. This study demonstrates the potential benefits of HTC processes for upgrading wet biomass waste streams based on continuous pilot-scale data.

Sustainable phosphorus recycling: A review of advanced recovery methods with a focus on hydrothermal humification technology and potential phosphorus resources in China for this method

AbstractThe management of phosphorus (P) resources is facing dual challenges mediated by human activities: the scarcity of bioavailable P in soil and the disposal of massive undeveloped P resources in waste streams. In China, large amounts of P resources remain unexploited, including crop straw (0.9 Tg/year), pig manure (1.1 Tg/year), sludges (0.2 Tg/year), faeces (0.5 Tg/year) and outbreaking algae (0.48 Tg/year). Traditional P recovery technologies, including precipitation, acidulation and thermochemistry technology (PAT) and enhanced biological phosphorus removal technology (EBPR), have shown limitations in P recovery from these biomass waste streams. Hydrothermal humification technology (HTH) is a promising new technology, capable of converting typical waste streams into phosphate fertilizer for green and sustainable development. We estimate that the amount of available P that HTH could potentially extract from straw, macroalgae waste and sludge totals 0.46 Tg/year. Accordingly, the consistent development of HTH for the recycling of waste P in biomass will effectively improve China's P cycle and relieve the absence of phosphate rock sources and environment pollution.

A waste-free biorefinery pathway to the valorisation of Chinese hickory shell through alkaline hydrogen peroxide pretreatment

Efficiently harnessing the intrinsic value of lignocellulose requires the integration of multifarious capacities within a zero-waste biorefinery. Chinese hickory shell, a food industry byproduct, remains largely untapped. Unleashing their full potential as a valuable biomass resource has become an urgent challenge. This study utilises the alkaline hydrogen peroxide pretreatment for Chinese hickory shell, exploring the effect of H2O2 dosage, alkali concentration, and temperature on lignocellulosic fractionation. Under optimal conditions, nearly complete removal of lignin and hemicelluloses is achieved, with cellulose enzymatic hydrolysis up to 98.1%, surpassing the original material by over 15-fold. Simultaneously, hemicelluloses transformed into high-value organic acids, yielding 33.5%. Notably, fractionated lignin is abundant in aryl ether linkages after AHP, facilitating subsequent transformation into aromatic chemicals. Through AHP, efficient fractionation of Chinese hickory shell is achieved, yielding fermentable glucose, organic acids, and lignin enriched with high aryl ether content. This research emphasises the pivotal role of comprehensive Chinese hickory shell utilisation in elevating the revenue of zero-waste biorefinery, sparking the production of valuable products from biomass waste streams, and further contributing to establishing resource-efficient biorefineries.

Biodiesel production from Sisymbrium irio as a potential novel biomass waste feedstock using homemade titania catalyst

Biomass waste streams are a possible feedstock for a range of eco-friendly products and a crucial alternative energy source for achieving carbon neutrality; therefore, the efficient management of biomass waste has taken on a greater significance in recent years. Due to its well-comparable physic-chemical properties with fossil diesel, biodiesel is a potential substitute for fossil fuel. This study aimed to synthesize biodiesel from the widely available non-edible seed oil of Sisymbrium irio L. (a member of the Brassicaceae family) via a transesterification procedure over a homemade TiO2 catalyst. At 1:16 oil to methanol ratio, 93% biodiesel yield was obtained over 20 mg catalyst at 60 °C and 60 min. The ASTM methods were used to analyze the fuel properties. The quantitative and qualitative analysis was performed by FT-IR, GC-MS, and NMR spectroscopy. GC-MS study confirms 16 different types of fatty acids of methyl esters. FT-IR analysis showed important peaks that confirm the successful occurrence of biodiesel. 1H-NMR and 13C-NMR showed important peaks for converting triglycerides into corresponding FAMEs. The acid value (0.42 mg KOH/mg/kg), flash point (106 °C), and water content (0.034) of biodiesel are below the specified limit of ASTM D6751 whereas kinetic viscosity (3.72 mm2/s), density (0.874 kg/L), cloud point (− 4.3 °C) and pour point (− 9.6 °C) and high heating value (41.62 MJ/kg) fall within the specified range of ASTM D6751 test limit. The Unsaturation degree and oxidative stability of biodiesel are above ASTM D6751 test limit. The physic-chemical properties of the SIB confirm that it is eco-friendly fuel and a competitive source for manufacturing biodiesel on a commercial scale. Furthermore, the SIB is engine friendly and has good fuel efficacy.

Nutrient recovery by microalgae in aqueous product of hydrothermal carbonization of dairy manure

Hydrothermal carbonization (HTC) is an emerging technology for energy recovery from wet biomass waste streams, including dairy manure. The HTC aqueous product (HAP) contains organic compounds and nutrients, requiring further treatment prior to environmental discharge. The goal of this study was to evaluate nutrient removal from dairy manure HAP using four species of microalgae: Chlamydomonas reinhardtii, Chlorella vulgaris, Arthrospira maxima, and Scenedesmus obliquus. The optimal HAP concentration for all species was 5% with little to no growth observed at lower dilutions. The highest nutrient removal occurred with A. maxima with > 93%, 33%, 81%, and 50% removal of NH3, NO3-, total nitrogen (TN), and total phosphorus (TP), respectively. Nutrient removal with the other species ranged from 35% to 82% of NH3, 29% to 35% of NO3-, 12% to 34% of TN, and 8% to78% of TP. Integrating HTC with microalgae cultivation is a promising treatment method for combined energy and nutrient recovery from dairy manure.

Depolymerisation–hydrogenation of condensed tannins as a strategy for generating flavan-3-ol monomers

A one-pot depolymerisation–hydrogenation xataltic process enables flavan-3-ol monomer production from condensed tannins.

Mitigation and adaptation strategies for a carbon neutral grape and wine sector

The Australian grape and wine sector has committed to reducing its carbon footprint by an active mitigation policy, concentrating in the shorter-term future on reducing Scope 1 and 2 emissions. Life cycle analyses for the sector indicate that carbon emission from grape growing and winemaking are small at 17% and 19% respectively; the major contribution of 68% is to do with packaging and transport (Scope 3), primarily involving use of glass bottles. Diesel use in vineyards is 41% of emissions and may be replaced with difficulty by vehicle electrification and/or hydrogen power. Replacement of winery grid-electricity use will account for 81% of emissions, with conversion to solar currently favoured. Opportunities exist to convert vineyard and winery biomass waste streams using pyrolysis to energy and biochar, the latter a form of sequestered carbon. The remaining large carbon emission relates to traditional use of glass packaging, with inherent weight and volume inefficiency increasing transport costs. Alternate packaging with lower carbon footprint and enhanced recyclability offers promise. The retail sector has opportunities to engage in “replace, recycle, or re-use” practices to reduce this footprint. The wine sector shares an ethical responsibility to mitigate climate change, not least because of impacts on grape and wine production.

Environmental Sustainability of Waste Circulation Models for Sugarcane Biorefinery System in Thailand

Sugarcane leaves and trash burning during harvesting, and vinasse management, are major challenges of the Thai sugarcane industry. Identification of the appropriate valorization pathways for both the biomass waste streams using the sugarcane biorefinery concept is necessary. This study aims to assess the environmental sustainability of five CE models, including (1) sugarcane trash for electricity, (2) sugarcane trash to biochar, (3) sugarcane trash as a soil conditioner, (4) vinasse as a bio-fertilizer, and (5) vinasse for power generation. Life cycle assessment has been conducted using the ReCiPE midpoint impact assessment method. The results revealed that all waste utilization scenarios can help reduce the environmental impacts compared to the base case. The utilization of sugarcane leaves and trash for electricity generation brings about the lowest environmental impacts due to the environmental credits from the substitution of Thai grid electricity. The utilization of sugarcane leaves can reduce impacts on climate change, terrestrial acidification, and ozone formation by about 20–104%, 43–61%, and 12–54%. Recycling vinasse as bio-fertilizer and for biogas production for electricity generation can reduce climate change impact by about 28–29%. There is a significant improvement of the avoidance of pre-harvesting burning of sugarcane in the Thai sugar industry, which has led to the big potential of sugarcane leaves biomass utilization. Recommendations to enhance the efficiency of using sugarcane leaves and vinasse are discussed. The integrated waste circulation scenarios on cane leaves and vinasses in the sugar-electricity-ethanol biorefinery shows advancement in the bio-circular-green economy (BCG) aspects for enhancing the environmental sustainability of the Thai sugarcane industry.

Deep Eutectic Solvents: Alternative Solvents for Biomass-Based Waste Valorization.

Innovative technologies can transform what are now considered “waste streams” into feedstocks for a range of products. Indeed, the use of biomass as a source of biopolymers and chemicals currently has a consolidated economic dimension, with well-developed and regulated markets, in which the evaluation of the manufacturing processes relies on specific criteria such as purity and yield, and respects defined regulatory parameters for the process safety. In this context, ionic liquids and deep eutectic solvents have been proposed as environmentally friendly solvents for applications related to biomass waste valorization. This mini-review draws attention to some recent advancements in the use of a series of new-solvent technologies, with an emphasis on deep eutectic solvents (DESs) as key players in the development of new processes for biomass waste valorization. This work aims to highlight the role and importance of DESs in the following three strategic areas: chitin recovery from biomass and isolation of valuable chemicals and biofuels from biomass waste streams.

Facile Synthesis and Life Cycle Assessment of Highly Active Magnetic Sorbent Composite Derived from Mixed Plastic and Biomass Waste for Water Remediation

Plastic and biomass waste pose a serious environmental risk; thus, herein, we mixed biomass waste with plastic bottle waste (PET) to produce char composite materials for producing a magnetic char composite for better separation when used in water treatment applications. This study also calculated the life cycle environmental impacts of the preparation of adsorbent material for 11 different indicator categories. For 1 functional unit (1 kg of pomace leaves as feedstock), abiotic depletion of fossil fuels and global warming potential were quantified as 7.17 MJ and 0.63 kg CO2 equiv for production of magnetic char composite materials. The magnetic char composite material (MPBC) was then used to remove crystal violet dye from its aqueous solution under various operational parameters. The kinetics and isotherm statistical theories showed that the sorption of CV dye onto MPBC was governed by pseudo-second-order, and Langmuir models, respectively. The quantitative assessment of sorption capacity clarifies that the produced MPBC exhibited an admirable ability of 256.41 mg g–1. Meanwhile, the recyclability of 92.4% of MPBC was demonstrated after 5 adsorption/desorption cycles. Findings from this study will inspire more sustainable and cost-effective production of magnetic sorbents, including those derived from combined plastic and biomass waste streams.

(Invited) Process Intensification of Electrochemical Systems for CO2 and Biomass Valorization

Valorization of CO2 and biomass waste streams via electrochemical conversions is a sustainable alternative for the production of fine chemicals and commodity chemicals. This topic has gained a lot of attention in the past decades and major research efforts have been put into it. Key advances has been achieved in the field of material development, where, novel catalysts have been synthesized, developed and have demonstrated to increase the efficiency and selectivity towards the targeted products. Relatively to the large number of studies focused on material development, limited studies are focused on process development, reactor optimization and product separation. Although material development is of paramount importance to achieve an adequate electrochemical reaction performance, it is only the first step needed in order to develop a competitive technology. Process development offers the possibility of enhancing the overall performance of the technology by looking not only at the reaction level, but finding engineering solutions to overcome critical limitations. Process development is essential in order to accelerate the technology towards its envisioned application and advance towards commercial realization. In this talk, we will present several optimization strategies (beyond material development) that helped increase the overall performance of several electrochemical conversion processes, as well as the economic profitability of the complete system.In addition, in order to advance the technology on the TRL scale and have a positive market potential, the technology needs to be evaluated in several aspects such as the scaling-up challenges, its cost competitiveness and its climate benefits. For this, it is crucial to consider the complete value chain, and evaluate not only the electrochemical reaction but also the upstream and the downstream processes. A complete system approach is paramount for the development of competitive technologies. In this talk we will also show several examples on different process intensification strategies and its benefits on the economic potential of them.

Maximizing net fuel economy improvement from fusel alcohol blends in gasoline using multivariate optimization

Fusel alcohol mixtures containing ethanol, isobutanol, isopentanol, and 2-phenylethanol have been shown to be a promising means to maximize renewable fuel yield from various biomass feedstocks and waste streams. We hypothesized that use of these fusel alcohol mixtures as a blending agent with gasoline can significantly lower the greenhouse gas emissions from the light-duty fleet. Since the composition of fusel alcohol mixtures derived from fermentation is dependent on a variety of factors such as biocatalyst selection and feedstock composition, multi-objective optimization was performed to identify optimal fusel alcohol blends in gasoline that simultaneously maximize thermodynamic efficiency gain and energy density. Pareto front analysis combined with fuel property predictions and a Merit Score-based metric led to prediction of optimal fusel alcohol-gasoline blends over a range of blending volumes. The optimal fusel blends were analyzed based on a Net Fuel Economy Improvement Potential metric for volumetric blending in a gasoline base fuel. The results demonstrate that various fusel alcohol blends provide the ability to maximize efficiency improvement while minimizing increases to blending vapor pressure and decreases to energy density compared to an ethanol-only bioblendstock. Fusel blends exhibit predicted Net Fuel Economy Improvement Potential comparable to neat ethanol when blended with gasoline in all scenarios, with increased improvement over ethanol at moderate to high bio-blendstock blending levels. The optimal fusel blend that was identified was a mixture of 90% v/v isobutanol and 10% v/v 2-phenylethanol, blended at 45% v/v with gasoline, yielding a predicted 4.67% increase in Net Fuel Economy Improvement Potential. These findings suggest that incorporation of fusel alcohols as a gasoline bioblendstock can improve both fuel performance and the net fuel yield of the bioethanol industry.

Valorisation of xylose to renewable fuels and chemicals, an essential step in augmenting the commercial viability of lignocellulosic biorefineries.

Biologists and engineers are making tremendous efforts in contributing to a sustainable and green society. To that end, there is growing interest in waste management and valorisation. Lignocellulosic biomass (LCB) is the most abundant material on the earth and an inevitable waste predominantly originating from agricultural residues, forest biomass and municipal solid waste streams. LCB serves as the renewable feedstock for clean and sustainable processes and products with low carbon emission. Cellulose and hemicellulose constitute the polymeric structure of LCB, which on depolymerisation liberates oligomeric or monomeric glucose and xylose, respectively. The preferential utilization of glucose and/or absence of the xylose metabolic pathway in microbial systems cause xylose valorization to be alienated and abandoned, a major bottleneck in the commercial viability of LCB-based biorefineries. Xylose is the second most abundant sugar in LCB, but a non-conventional industrial substrate unlike glucose. The current review seeks to summarize the recent developments in the biological conversion of xylose into a myriad of sustainable products and associated challenges. The review discusses the microbiology, genetics, and biochemistry of xylose metabolism with hurdles requiring debottlenecking for efficient xylose assimilation. It further describes the product formation by microbial cell factories which can assimilate xylose naturally and rewiring of metabolic networks to ameliorate xylose-based bioproduction in native as well as non-native strains. The review also includes a case study that provides an argument on a suitable pathway for optimal cell growth and succinic acid (SA) production from xylose through elementary flux mode analysis. Finally, a product portfolio from xylose bioconversion has been evaluated along with significant developments made through enzyme, metabolic and process engineering approaches, to maximize the product titers and yield, eventually empowering LCB-based biorefineries. Towards the end, the review is wrapped up with current challenges, concluding remarks, and prospects with an argument for intense future research into xylose-based biorefineries.

Intensification of formic acid from dilute aqueous solutions using menthol based hydrophobic deep eutectic solvents

The fermentation of biomass and organic waste streams is the primary source of formic acid production. Formic acid is the hydrogen energy carrier and is used as a hydrogen storage medium in fuel cells. Sustainable production of formic acid makes the hydrogen-fuel cell entirely environmentally friendly and ensures the long-term storage of renewable energy. Therefore, green, economic, and sustainable production and recovery of formic acid are highly demanded. In this study, it was aimed to use a new generation, green, easily prepared, and designer hydrophobic deep eutectic solvents (HDES) for the removal of formic acid via reactive extraction. HDESs obtained by preparing binary mixtures of nonanoic acid, decanoic acid, dodecanoic acid (HBD), and menthol (HBA) were used as diluents; tri-n-octylamine (TOA) and Amberlite LA-2 (Amb.LA-2) were acted as extractants. Experiments were performed to investigate the effect of extractant type and concentration, initial acid concentration, and volume of the organic phase on extraction. Experimental data were presented by calculating the extraction efficiency (E%), distribution coefficient (D), and loading factor (Z). Results demonstrated that the extraction efficiency remained between 10 and 13% when performing physical extraction using M-NA, M-DA, and M-DDA, while TOA was diluted with the same HDESs reached around 90% and with Amb.LA-2 85%. The highest distribution coefficient was obtained that the organic phase consisting of TOA and M-DDA mixture was used. The efficiency of utilized HDESs was in the following order: M-DDA ​> ​M-DA ​> ​M-NA.

Potential Valorization of Organic Waste Streams to Valuable Organic Acids through Microbial Conversion: A South African Case Study

The notion of a “biobased economy” in the context of a developing country such as South Africa (SA) necessitates the development of technologies that utilize sustainable feedstocks, have simple and robust operations, are feasible at small scale and produce a variety of valuable bioproducts, thus fitting the biorefinery concept. This case study focuses on the microbial production of higher-value products from selected organic waste streams abundant in the South African agricultural sector using microbes adapted to utilize different parts of biomass waste streams. A ruminant-based carboxylate platform based on mixed or undefined anaerobic co-cultures of rumen microorganisms can convert the carbohydrate polymers in the lignocellulosic part of organic waste streams to carboxylic acids that can be upgraded to biofuels or green chemicals. Furthermore, yeast and fungi can convert the simpler carbohydrates (such as the sugars and malic acid in grape and apple pomace) to ethanol and high-value carboxylic acids, such as lactic, fumaric, succinic and citric acid. This review will discuss the combinational use of the ruminal carboxylate platform and native or recombinant yeasts to valorize biomass waste streams through the production of higher-value organic acids with various applications.

Valorization of Waste Apple Pomace for Production of Platform Biochemicals: A Multi-Objective Optimization Study

In line with the prevailing global interest in value extraction from biomass waste streams, the current study explored the technical feasibility of valorizing waste apple pomace (WAP) to produce high-value biochemicals of 5-hydroxymethylfurfural (HMF), lactic acid, and xylitol. Technical feasibility was demonstrated via a process simulation study that employed experimental data and incorporated previously reported approaches in the literature. Economic and environmental performances of the WAP based biorefinery were assessed using the internal rate of return (IRR) and the mass of greenhouse gas emission per unit mass of feedstock (GF) as sufficient performance indicators, respectively. The study was able to show that as the IRR value increased (better economic performance), the GF increased (poorer environmental performance). This suggested that the determination of the optimal condition of the environmental and economic performances would require the imposition of trade-offs. The preferred trade-off condition for enhanced economic and environmental performances was subsequently determined via multi-objective optimization, with a Pareto front containing non-dominated equally optimal solutions subsequently developed. The present work, therefore, provides an in-depth performance analysis of WAP based biorefinery as a waste management strategy. Notably, the proposed strategy of multiple product generation from biomass may be extended to other organic waste based biorefineries.

Increasing Access to Electricity: An Assessment of the Energy and Power Generation Potential from Biomass Waste Residues in Tanzania

Tanzania has a high rural population, of which many rely on off-grid diesel generators to produce electricity. The focus of this paper is to assess if the waste biomass residues in Tanzania have sufficient energy potential to produce renewable electrical energy for small-scale electricity generation using off-grid diesel generators coupled with anaerobic digestion (AD) and/or gasification. The gaseous fuel produced can then be used to substitute diesel fuel used in small-scale dual fuel diesel gen-sets; thus, providing more affordable electricity whilst reducing dependency on fossil fuels. The biomass waste streams estimated are those arising from agriculture, forestry, livestock, and urban human waste. To answer this question, the energy potentials of each of these biomass waste streams are quantified, followed by further calculations to determine the electricity generation capacity per stream based on overall efficiencies of 10 and 25%. The results show that combined these waste streams have an energy potential of 385 PJ (for the base year of 2018) generated from 26,924 kilotonnes (kt). Collectively, these residues can produce at least 1.2 times the electricity generated nationally in 2018 using AD and gasification coupled with a diesel gen-set engine.