Wheat Straw Research Articles

Ash Formation and Associated Interactions during Co-Combustion of Wheat Straw and Sewage Sludge

The aim of the present work was to investigate ash formation and associated interactions during the pulverized fuel co-combustion of biomass fuels. Combustion experiments were carried out with narrowly sized wheat straw (WS), sewage sludge (SS), and their blends in a drop tube furnace at 1100 °C and 1300 °C. The resulting residual ash and fine particulate matter (PM10) were characterized with various analyses. It was observed that co-combustion influences size distributions of the residual ash particles and generally generates larger residual ash particles close to those of SS combustion. The interaction of K capture by minerals enhances the melting and consequently increases the production of large and melting ash particles during co-combustion. It was found that blending SS with WS has not only the positive interaction of K capture by minerals from SS ash to significantly reduce submicron ash formation, but also the positive interaction of transforming alkali chlorides into alkali sulfates to reduce the corrosiveness of submicron ash particles. Co-combustion of SS with WS can also reduce the presence of alkali chloride at PM1–10, lowering the propensities of deposition and corrosion of the fine residual ash particles.

Chitosan/magnetic biochar composite with enhanced reusability: Synergistic effect of functional groups and multilayer structure

Heavy metals in water bodies pose a significant threat to both ecology and human well-being. Therefore, the development of green and sustainable adsorbents for water remediation is essential. This study presents a crosslinked chitosan composite structure with multiple layers, which was generated by adjusting the ratio of chitosan to wheat straw–derived magnetic biochar in the composite. The adsorption behavior of the composite under different conditions was revealed by varying the Cr(VI) concentration, pH, and temperature. The composite exhibited a maximum adsorption of 121.8 mg g−1 for Cr(VI) in water, which was 11.9 times higher than that of magnetic biochar. It maintained a residual performance of 78.6 % after seven cycles, higher than most chitosan-based composites. The reusability was improved via hydrochloric acid protonation of functional groups and layer-by-layer exposure of the composite structure. This study provides new insights into the application of composites derived from chitosan and wheat straw, an agricultural waste, as sustainable adsorbents.

Recovery of sulfuric acid during sugar purification from pretreated wheat straw hydrolysate using electro-electrodialysis system for 2G bioethanol production

Concentrated acid hydrolysis (CAH) of lignocellulosic biomass (LCB) is an established method to obtain a near theoretical yield of monomeric sugars from the biomass. The CAH process produced 83.23 % of glucose from pretreated wheat straw (PWS) at optimum conditions (i.e., stage I = 74 % w/w acid, 1:2 biomass loading, and 50 °C for 1 h; and stage II = 30 % w/w acid, 90 °C for 2 h). However, the separation of sugar from acidic hydrolysate is a major constraint of this technology. In this study, an electro-electrodialysis (EED) process using a novel anion exchange membrane (AEM) has been developed to recover sulfuric acid from biomass hydrolysate. The synthetic hydrolysate (i.e., feed acid concentration = 2 M; glucose = 80 g L−1) was used to optimize the EED process parameters. The acid was successfully recovered from alkali pretreated wheat straw (PWS) hydrolysate using the most effective EED process parameters. This resulted in an 82.72 % acid recovery in the permeate under the following conditions: current density of 88 mA cm−2, flow rate of 3 L h−1, and feed acid content of 2 M. During the EED process, the highest glucose recovery in the feed was 90.98 %, achieved with a maximum current efficiency of 93.57 % and the lowest energy consumption of 0.052 kW h mol−1 at optimal conditions using PWS Hydrolysate. Saccharomyces cerevisiae fermented the acid-free PWS hydrolysate, resulting in a maximum ethanol yield of 92.3 %. The EED process cost of $0.049 kg H2SO4−1 and total revenue was $0.02 kg biomass−1 from the second batch onwards suggest the feasibility of the EED process for large-scale 2G bioethanol productions.

Effects of zinc oxide nanoparticles on carbon mineralization kinetics and microbial attributes in plant residue-amended soils

This study was designed to determine the impacts of different ZnO-NPs concentrations (100–1000 mg kg−1 soil) on soil carbon (C) mineralization of a calcareous soil amended with alfalfa hay (AH) and wheat straw (WS). In addition, C mineralization kinetics in the residue-amended soils were described using different kinetic models and the impacts of ZnO-NPs on the kinetic parameters were investigated. The microbial biomass C (MBC) and basal respiration (BR) were also compared in the treated and control soil samples. The findings revealed a significant reduction in total cumulative mineralized C (Cmin) in soil amended with AH at ZnO-NPs concentrations of 100 and 200 mg−1 kg soil. Similarly, in soil samples amended with WS, the Cmin value demonstrated a significant decrease across all ZnO-NPs concentrations, except for the lowest concentration of 100 mg−1 kg soil. The results of kinetic analysis using the double first-order model showed that the introduction of ZnO-NPs led to an increase of up to 147 % in the amount of C mineralization during the initial fast phase, while it also resulted in a reduction of up to 27.3 % in C mineralization during the subsequent slow phase. Moreover, the presence of ZnO-NPs in the soil resulted in a noteworthy decrease of 4.44 % to 54.5 % in MBC and 5.12 % to 35.7 % in BR values when compared to the uncontaminated soil, suggesting that the size and activity of the soil microbial community were suppressed, with the extent of suppression varying depending on the type of plant residues and concentrations of ZnO-NPs applied. These findings strongly suggest that the soil microbial community was subjected to heightened toxicity stress caused by ZnO-NPs, particularly at higher concentrations. In conclusion, ZnO-NPs can drastically influence the microbial abundance, maintenance energy demand, and C mineralization process in plant residue-amended calcareous soils.

Taxon-specific ability of saprophagous soil macrofauna to reintegrate carbon from agricultural waste into soil

Saprophagous soil macroinvertebrates may potentially degrade agricultural wastes. However, it is not known, to what extent and representatives of which taxa may help reintegrating carbon from crop residues back into soil without triggering massive carbon release into the atmosphere. To tackle this problem, we conducted a three-month-long microcosm experiment with 21 different species of macrofauna (each treatment replicated four times) belonging to 13 families to test their ability to degrade wheat straw. Simultaneously CO2 release from the microcosms was measured. Five species did not survive under experimental conditions. Among the remaining 16 species, three significantly increased wheat straw decomposition with Oryctes nasicornis larvae having inflicted the highest straw mass loss (64%) in comparison with the control, where no animals were added (29%). None of the tested species increased cumulative CO2 evolution from the microcosms, while two species significantly reduced it. The reduction of carbon loss with aerobic respiration was recorded for Cetonia aurata larvae and the earthworm Dendrobaena veneta (respectively 2.5 and 2-fold in relation to the control – 53.8±4.6 mg CO2-C g−1 soil dry weight during the entire experiment). The original integrative Carbon Sequestration Index by Macrofauna (CSIM) calculated for both of the measured parameters suggests that the woodlouse Armadillidium vulgare and to a smaller extent the earthworm D. veneta appear to be the most promising organisms for industrial climate-friendly organic waste recycling in terms of survival, straw processing and simultaneous reduction of CO2 emissions from soil. Our results proved that the engagement of saprophagous macrofauna in crop residue decomposition is a viable technique of carbon reincorporation into the soil. It is accompanied with CO2 release mitigation into the atmosphere.

Effect of Pulping Waste Liquid on the Physicochemical Properties and the Prediction Model of Wheat Straw Residue Granular Fuels.

Herein, wheat straw residue and pulping waste liquid were collected from pulping mill and mixed to prepare bio-based granular fuels by using compression molding technology, and to explore the comprehensive utilization of the industrial waste of pulping and papermaking. The effects of pulping waste liquid on granular fuel properties were analyzed systemically. Further study of the function of pulping waste liquid, cellulose and hemicellulose was used to replace wheat straw residue and avoid the interference factors. Therefore, the prediction models of granular fuels were established with influencing factors that included cellulose, hemicellulose and pulping waste liquid. The granular fuels had the best performance with 18.30% solid content of pulping waste liquid. The highest transverse compressive strength of granular fuel was 102.61 MPa, and the activation energy was 81.71 KJ·mol-1. A series of curve fitting prediction models were established to clarify the forming process of granular fuel, and it turned out that the pulping waste liquid could improve the adhesion between solid particles and increase their compression resistance.

Cadmium immobilization in soil using phosphate modified biochar derived from wheat straw

The phosphate-modified biochar (BC) immobilizes cadmium (Cd), yet little is known about how phosphate species affect Cd detoxification in contaminated soils. We developed phosphate-modified biochar through the pyrolysis of wheat straw impregnated with three types of phosphate: mono‑potassium phosphate (MKP), dipotassium hydrogen phosphate (DKP), and tripotassium phosphate (TKP). The Cd adsorption mechanism of modified biochar was investigated by biochar characterization, adsorption performance evaluation, and soil incubation tests. The results demonstrated that the efficiency of biochar in immobilizing Cd2+ followed the order: TKP-BC > DKP-BC > MKP-BC. The TKP-BC had the highest orthophosphate content, the fastest adsorption rate, and the largest adsorption capacity (Langmuir) of 257.28 mg/g, which is 6.31 times higher than that of the unmodified BC (CK). In contrast, pyrophosphate was predominant in MKP-BC and DKP-BC. The primary adsorption mechanism for Cd2+ was precipitation, followed by cation exchange, as evidenced by the formation of CdP minerals on the BC surface, and an increase of K+ in solution (compared to water-soluble K+) and a decrease of K+ in the biochar during adsorption. Desorption of Cd from the TKP-BC after adsorption was 9.77 %–12.39 % at a pH of 5–9, much lower than that of CK. The soil incubation test showed the diethylenetriaminepentaacetic acid extracted Cd of TKP-BC, MKP-BC, and DKP-BC was reduced by 67.93 %, 18.41 % and 31.30 % over CK, respectively. Using the planar optodes technique, we also found that TKP-BC had the longest effect enhancing in situ soil pH. This study provides a theoretical basis for developing heavy metal pollution control technology using green remediation materials and offers insights into the remediation mechanisms.

Improve nutritive value of silage based on prickly pear peel by-products

Prickly pear (Opuntia ficus-indica L. Mill) is widely cultivated in arid regions of every continent for its nutritious fruits and various commercial applications, cactus pear cladodes are used as forage in the most arid regions, while recently prickly pear by-products are studied as ruminant feed. They are characterised by a high moisture and sugar content; therefore, it is necessary to study suitable conservation methods. The aim of this study was to verify the effectiveness of silage to preserve prickly pear peels (PP) in a mixture with other by-products at different inclusion levels (5% straw and 6% or 12% wheat bran). For each treatment, six under vacuum micro-silos were prepared and, after 40 d of storage, the state of preservation was evaluated. Subsequently, the aliquots were analysed for chemical composition and incubated with sheep rumen fluid to evaluate the fermentation kinetics. The use of wheat bran and straw added to PP resulted in an increase in dry matter (DM); PP silage with wheat bran was found to have higher protein content and nutritional value. The greater presence of lactic acid was found in PP, such as acetic acid, therefore the lactic/acetic ratio was 2.33, significantly lower than silages with the addition of wheat bran. Silage with 5% straw showed the lowest level of organic matter disappearance (OMD) and the cumulative volume of gas (OMCV) produced during the incubation. The PP showed the fastest fermentation rate achieved after 12 h of fermentation, while those containing wheat bran, presented a higher maximum fermentation rate (Rmax), which need longer time to be achieved. Canonical discriminant analysis (CDA) showed clear discrimination of different silages based on their chemical characteristics and parameters detected during in vitro incubation. Overall, the silages with the addition of wheat bran can be considered the best and, of the two, those produced with the addition of 12% bran. Finally, ensilage represents a conservation technique suitable for preserving the nutritional characteristics of PP.

Green recovery of platform chemicals from hydrothermal carbonization process water

This study explores the side-recovery of platform chemicals in the hydrothermal carbonization waste-to-energy chain. Up to 90 % of target chemicals, furfural and 5-hydroxymethylfurfural, were green extracted from the process waters using the hydrophobic deep eutectic solvent decanoic acid/thymol. Wheat straw and rice husk reacted (1/4 solid/water ratio) for up to 120 min and at 180 and 230 °C. The dissolved chemicals built up to 5.9 g/L, accounting for 12 % of the total carbon. Extractions from the process waters and those from reference solutions behaved similarly. The solvent affinity toward furfural is 3.5 times higher than that of 5-hydroxymethylfurfural. The aqueous raffinates chromatographic outline demonstrated the recyclability for prosecuting the HTC. Focused experiments mimicked the functioning of an industrial cascade of two crosscurrent mixer settlers. Extraction yields were 90.7 and 65.8 % for furfural and 5-hydroxymethylfurfural. The counterflow arrangement, simulated by the Kremser method, gave corresponding higher yields, 96.9 and 73.4 %, respectively.

Lignin-Based Hydrogels for the Delivery of Bioactive Chaga Mushroom Extract.

Lignin-poly(ethylene)glycol diglycidyl ether hydrogels were synthesized from lignin fractions readily extracted during the hot-water treatment of angiosperms: hardwoods, sugar maple and energy-crop willow, monocotyledons, grasses, miscanthus and agriculture residues, and wheat straw. These lignins represent a broad range of chemical structures and properties as a comparative analysis of their suitability to produce the hydrogels as a novel carrier of chaga-silver nanoparticles. The formation of hydrogels was assessed via attenuated total reflectance Fourier-transformed infrared spectroscopy. Then, the hydrogels were observed via scanning electron microscopy and evaluated for their free-absorbency capacity and moduli of compression. Furthermore, a hydrogel produced from kraft lignin and two commercial hydrogels was evaluated to benchmark the effectiveness of our hydrogels. Chaga extracts were prepared via the hot-water extraction of chaga mushroom, a method selected for its relatively higher yields and preserved antioxidizing activities. Hydrogels synthesized with lignins of monocotyledons, wheat straw, and miscanthus were found to be suitable carriers for chaga-silver nanoparticles due to their favorable absorption and release behaviors.

Organic fertilizers in increase of hazelnut yield

Goal. To assess the effect of various organic fertilizers on the yield of hazelnut plantations in the conditions of the Southern Steppe of Ukraine.
 Methods. Field experiment, laboratory-analytical, comparative.
 Results. The influence of organic fertilizers of various origins was studied (cattle manure; chicken droppings; Biofertilizer No. 1 — sewage sludge (SW) of the biological treatment station (SBO) «Pivdenna» in Odesa + winter wheat straw + Microbacterium barkeri LP-1 (M. b.); Biofertilizer No. 2 — «Southern» SBO + sunflower seed husks + M. b.; «Pivdenna» SBO, Odesa) on the agrochemical parameters of ordinary medium-humus chernozem in the conditions of the Southern Steppe of Ukraine for the cultivation of hazelnuts. It is shown that in comparison with the control of 2021 and 2022, an increase in the content of easily hydrolyzed nitrogen, mobile forms of phosphorus and potassium, and organic matter is noted in all variants of the experiment.
 Conclusions. The use of organic fertilizers of various origins for the cultivation of hazelnuts in the conditions of the Southern Steppe of Ukraine helps to increase the content of the main agrochemical indicators of the soil — easily hydrolyzed nitrogen (91.0—98.0 mg/kg with 84.0 mg/kg — control), mobile phosphorus compounds (174.75—306.30 mg/kg at 138.75 mg/kg — control), potassium (112.00—166.90 mg/kg at 108.40 mg/kg — control) and organic matter (3.78—4.18% and 3.76% — control). The advantages of biofertilizers No. 1 and No. 2 based on sewage sludge with the use of vegetable fillers (winter wheat straw and sunflower seed husks) and the phosphate-mobilizing bacterium Microbacterium barkeri LP-1 are shown. Organic fertilizers contribute to the increase in the content of nutrients in the soil, the activation of the activity of eco-trophic groups of microorganisms, which leads to an increase in the biological activity of the soil and, accordingly, the yield of agricultural crops.

Biochar impacts on carbon dioxide, methane emission, and cadmium accumulation in rice from Cd-contaminated soils; A meta-analysis

Climate change and cadmium (Cd) contamination pose severe threats to rice production and food security. Biochar (BC) has emerged as a promising soil amendment for mitigating these challenges. To investigate the BC effects on paddy soil upon GHG emissions, Cd bioavailability, and its accumulation, a meta-analysis of published data from 2000 to 2023 was performed. Data Manager 5.3 and GetData plot Digitizer software were used to obtain and process the data for selected parameters. Our results showed a significant increase of 18% in soil pH with sewage sludge BC application, while 9% increase in soil organic carbon (SOC) using bamboo chips BC. There was a significant reduction in soil bulk density (8%), but no significant effects were observed for soil porosity, except for wheat straw BC which reduced the soil porosity by 6%. Sewage sludge and bamboo chips BC significantly reduced carbon dioxide (CO2) by 7–8% while municipal biowaste reduced methane (CH4) emissions by 2%. In the case of heavy metals, sunflower seedshells-derived materials and rice husk BC significantly reduced the bioavailable Cd in paddy soils by 24% and 12%, respectively. Cd uptake by rice roots was lowered considerably by the addition of kitchen waste (22%), peanut hulls (21%), and corn cob (15%) based BC. Similarly, cotton sticks, kitchen waste, peanut hulls, and rice husk BC restricted Cd translocation from rice roots to shoots by 22%, 27%, 20%, and 19%, respectively, while sawdust and rice husk-based BC were effective for reducing Cd accumulation in rice grains by 25% and 13%. Regarding rice yield, cotton sticks-based BC significantly increased the yield by 37% in Cd-contaminated paddy soil. The meta-analysis demonstrated that BC is an effective and multi-pronged strategy for sustainable and resilient rice cultivation by lowering greenhouse gas emissions and Cd accumulation while improving yields under the increasing threat of climate change.

Employing soil isolated fungi for production of bioactive phenolic compounds: a fermentative approach

An efficient method of solid-state fermentation (SSF) is reported for producing bioactive phenolic compounds using soil-isolated fungi. Antioxidant activity using a rapid DPPH (1,1-diphenyl-2-picryl hydrazyl), was employed to screen the 120 fungal isolates from soil. Aspergillus terreus 1, Aspergillus fumigatus, Aspergillus terreus 2, Penicillium citrinum, Aspergillus wentii1, Aspergillus wentii 2, Penicillium expansum and Penicillium granulatum were chosen, concerning their antioxidant activity and total phenolic content. These fungal strains were applied on agro residues viz. sugarcane bagasse, corn cob, rice straw, pea pod and wheat straw, to evaluate the release of phenolic compounds. The fermented extracts from various agro-residues showed good antioxidant activity against DPPH, ferric ion, and nitric oxide radicals. The highest antioxidant activity was observed in fermented extracts of sugarcane bagasse, followed by pea pod. Additionally, the total phenolic content in the fermented extracts positively correlated with antioxidant potential. This study highlights the significant potential of solid substrate fermentation using soil-isolated fungi and agro-residues to produce bioactive phenolic compounds with potent antioxidant properties. The utilization of SSF for the extraction of bioactive compounds from natural sources not only offers a clean and sustainable approach but also contributes to the valorization of agro-industrial residues.

Sustainable indigenous bio-mixture for restoration the soil point source pollution with special reference to chlorpyrifos

Improper pesticide handling is the main cause of contamination of the environment in agricultural systems. This could be caused by leakage of spraying liquid, leftovers, and inappropriate washing of spraying equipment. This study assessed the ability of suggested biomixture modules for remediate repetitive cycles of high chlorpyrifos doses. In three consecutive treatments, four tested modules were contaminated with 160 µg g−1 chlorpyrifos. Chlorpyrifos residues, dehydrogenase activity, and microbial respiration were continuously monitored for 22 weeks. Six bacterial consortia were isolated at the end of the experiment from four treated modules (B+3, BF+3, S+3, and SF+3) and two from untreated modules (B and S). The isolated consortium efficiency in degrading chlorpyrifos was studied. The results revealed that the best chlorpyrifos removal efficiency was achieved when using the stimulated biomixture module (BF) recorded 98%, 100%, and 89%, at the end of three chlorpyrifos treatments, respectively. Such removal efficiency was compatible with the biological activity results of the tested modules: dehydrogenase activity and microbial respiration. There was no difference in the efficiency among the S, B, and BF+3 consortia. The results presented here demonstrate that the combination of vermicompost, wheat straw, soil, and NPK (stimulated biomixture module) can successfully reduce the risk of a point source of pesticide pollution.

Crop‐ and weather‐dependent yield and wind erosion benefits from a conservation practices system

AbstractWind erosion and variable weather challenge crop production in the northern Great Plains. Management that increases residue cover might mitigate wind erosion during the cash crop growing season. We evaluated horizontal sediment flux (modified Wilson and Cooke samplers) and cash crop yield across a single rotation of corn (Zea mays L.)–soybean (Glycine max (L.) Merr.)–spring wheat (Triticum aestivum L.) in paired fields with contrasting management. One field included cover crops and retained spring wheat straw (aspirational), while the other excluded both conservation practices over the 3‐year rotation (business‐as‐usual). Horizontal sediment flux rapidly decreased with days after cash crop planting (increasing crop canopy), regardless of management treatment. In 2 years (2020 corn and 2022 spring wheat), there was greater horizontal sediment flux, lower cash crop grain yield, and lower cash crop aboveground biomass in the aspirational versus business‐as‐usual field. In 2021 soybean, there was lower horizontal sediment flux, greater cash crop yield, and greater cash crop aboveground biomass in the aspirational versus business‐as‐usual field. Higher yield and lower horizontal sediment flux responses corresponded with the management treatment that produced the higher cash crop aboveground biomass. Additionally, our short‐term study indicated that in drought years, cover crops worsened the adverse effects of abnormally low precipitation on yield and biomass of 2020 corn but not 2021 soybean.

A biotechnological approach to upgrade wheat straw into high-performance binderless boards

Wheat straw represents a highly promising source for the production of bio-based materials due to its fibrous composition, naturally optimized structure, and high availability as an agricultural by-product. The present study reports the conversion of wheat straw into high-performing fibreboards without the use of bonding agents. In a first step, straw was converted into fibres using a mild semi chemical pulping process. Subsequently, microbial aqueous retting of the fibres was performed for different periods. The fibres obtained were characterized and the microorganisms involved in the retting process were isolated and sequenced. Quantification of xylanase activity indicated substantial enzymatic hydrolysis of hemicellulose. This biotreatment improved both the drainability of the straw fibres and the mechanical properties of hot-pressed binderless fibreboards. Characterization of mechanical and physical properties revealed impressive flexural strengths of 64 MPa, flexural moduli of 6.8 GPa and internal bond of 1.1 MPa after 8 days of bio treatment. The results exceeded the standard requirements for hardboards and demonstrate the possibility of enhancing the performance of straw based binderless boards with natural biotreatment.

Evaluation of urea loaded nanoclay biopolymer composites with Zn and P solubilizing microbes for nitrogen uptake and use efficiency in maize (Zea mays)-wheat (Triticum aestivum) cropping system

A field experiment was conducted during rainy (kharif) 2022 (July 2022–October 2022) and winter (rabi) 2022–23 (November 2022–March 2023) seasons at ICAR-Indian Agricultural Research Institute, New Delhi to evaluate a series of Zn and P solubilizing microbial culture enriched nanoclay biopolymer composite (NCBPC) loaded with nitrogenous fertilizer (urea) and the efficiency of the products for maize (Zea mays L.) and wheat (Triticum aestivum L.). Experiment consisted of 10 treatments, viz. T1, Control; T2, 100% N though urea; T3; T5; T7; and T9, 75% N as urea loaded NCBPC-A (prepared using acrylic acid + acrylamide + mango kernel flour) alone or along with P or Zn or P + Zn solubilizers; T4; T6; T8 and T10, 75% N as urea loaded NCBPC-B (prepared using acrylic acid + acrylamide + maize flour) alone or along with P or Zn or P + Zn solubilizers in a randomized block design (RBD) and replicated thrice. In both maize and wheat crop, highest grain (5.09 and 5.32 t/ha) and straw yield (6.56 and 7.45 t/ha), apparent N recovery (51.26 and 47.26%) and agronomic efficiency (12 and 13.3 kg grain yield obtained/kg N application) were obtained in treatment T10 followed by T9. In addition, total N uptake significantly enhanced by 20.1–28.4% in maize and 22.1–30.8% in wheat (T9 and T10); apparent nitrogen recovery (ANR) improved by 12.9–18.2 and 15.2–21.1% and agronomic efficiency (AE) triggered by 19.5–21.2 and 15.4–20.8% in maize and wheat crops respectively, under T9 and T10 treatments over standard urea fertilization (T2). Thus, the study concludes that, 25% N requirement could be cut down through application of 75% N (urea) loaded NCBPCs in conjunction with Zn or P or Zn + P solubilizing microbial culture as compared to sole urea application under maize-wheat cropping system.

Valorization of kiwi waste through composting

ABSTRACT Kiwi waste from the calibration process is a major environmental problem of kiwi production due to landfill deposition. This work aims to contribute to the agronomic use of recycled kiwi waste through composting. With this objective, a composting experiment was carried out with kiwi fruit waste mixed with 5%, 10% and 20% (fresh weight) of wheat straw from bundles used to protect kiwifruit trunks from frost, as abulking agent to increase aeration, in the piles 5S, 10S and 20S, respectively. The highest temperatures for piles 5S and 10S were above 60°C, whereas the temperature did not reach 40°C in the pile with the highest straw content (20S) because the aeration increased heat loss in addition to increased C/N ratio of this pile. Also, the amount of organic matter mineralized decreased with increasing amount of straw because of the high C/N ratio of the straw. The highest total N (29.7 g kg−1) and the lowest C/N ratio (13) of the compost with 5% of straw is important from the agricultural point of view to promote N availability. In contrast, the high electrical conductivity (4.6 dS m−1) of this compost increases the risk of salt accumulation in the soil. Our results show that the compost with 10% straw, with high degree of maturation, absence of poor hygiene indicators as coliforms and pathogens as Salmonella sp., high organic matter content and rich in nutrients, together with the adequate compost pH and low electrical conductivity improves compost quality.

Recent Advances in the Application of Agricultural Waste in Construction

On a global scale, millions of tons of diverse agricultural residues are generated annually. Most of these wastes are burned or dumped in landfills, which causes environmental pollution. Addressing environmental issues arising from agricultural waste materials, in addition to mitigating heating and cooling expenses in the construction sector, is an interesting challenge for researchers. The utilization of agricultural wastes in different parts of construction is producing positive findings day by day, and investigating research in this field is a curiosity for researchers. This short study reviewed the most recent achievements in using agricultural wastes as a substitute or additive material for construction. Using these wastes as aggregate, ash (as a supplementary for cement), or fibers for foam concrete, insulation materials, etc. has been reviewed. This review has focused on very recent published papers. Several studies have demonstrated the effective influences of agro-waste materials in construction, like retaining the compressive strength (155 MPa) of concrete at standard levels and reducing heat losses in buildings (69% energy savings for brick insulated using wheat straw), as well as sound insulation. The use of agro-waste materials for insulation positively improved thermal conductivity, costs, and energy savings. However, some wastes did not provide a high added value, which shows that more investigations still need be performed to fill this gap in the research. Considering the global scale of agricultural waste generation and the potential benefits to both the environment and construction industry, continued research in this area is essential.

Effects of mild acid pre-treatment on the co-pyrolysis behaviour of biosolids and wheat straw

Co-pyrolysis of biosolids (BS) and wheat straw (WS), as well as their treated variants, was performed in a fluidised bed reactor at 500 ℃. Under mild acid pre-treatment conditions (3% H2SO4 and 25 ℃), demineralisation was the dominating effect of pre-treatment on BS, while it was hemicellulose hydrolysis for WS. Consequently, the co-pyrolysis of raw biosolids (RBS) or treated biosolids (TBS) with raw wheat straw (RWS) or treated wheat straw (TWS) had varying effects on product distribution and product compositions. The co-pyrolysis of RBS+RWS gave the lowest bio-oil yield (36.3 wt%) and highest gas yield (23.1 wt%). In contrast, the highest bio-oil yield (45.8 wt%) and lowest gas yield (14.4 wt%) occurred during the co-pyrolysis of TBS+TWS. The degree of synergy in product distribution was strongest in TBS+RWS followed by RBS+RWS and was weakest in TBS+TWS, demonstrating the catalytic effect of inherent minerals on organic matter devolatilisation and char cracking reactions during co-pyrolysis. Biosolids pre-treatment alone performed competitively with BS co-pyrolysis alone with respect to enhancement in biochar properties producing biochar having 15–18 MJ/kg calorific value, 43–51 wt% carbon content, 0.7–1.0 fuel ratio, ⁓30% organic matter retention, and 27–41 wt% ash content. However, combining BS co-pyrolysis and pre-treatment gave the lowest reduction in biochar total heavy metal concentration. Furthermore, bio-oil compositions were influenced by pre-treatment and/or co-pyrolysis, increasing the yield (area%) of phenols to 25.4%, furans to 24.8%, anhydrosugars to 7.8%, and aromatic hydrocarbons to 20.6%. Lastly, pre-treatment alone weakened gas production while co-pyrolysis combined with pre-treatment impacted the pyrolysis gas profile, switching between light hydrocarbons and carbon oxides (CO and CO2). Overall, co-pyrolysis and pre-treatment can each be a standalone strategy for enhancing BS pyrolysis; however, their combination produced greater synergy for generating high value products.