Agro-industrial Solid Waste Research Articles

New approach to agro-industrial solid and liquid waste management: Performance of an EGSB reactor at different hydraulic retention times for methane production

This study investigated the removal of agro-industrial wastes (5 g COD L⁻1 from coffee and 0.5 g COD L⁻1 from brewery wastewater, plus 1 g L⁻1 of coffee pulp and husk) in a continuous Expanded Granular Sludge Bed (EGSB) reactor at 35 °C. The effect of Hydraulic Retention Times (HRTs) of 72h, 48h, and 24h on CH₄ yield was examined using a mixed culture of cattle manure and granular sludge. Methane yields were 201, 124.5, and 113.8 mL CH₄ g⁻1 COD for the 1st, 2nd, and 3rd phases, respectively. Volatile fatty acids, particularly acetic acid, increased at lower HRTs. Sequencing of the 16S rRNA gene on the Illumina HiSeq platform revealed a syntrophic relationship between Syntrophorhabdus, Syntrophobacter, and Pseudomonas with methanogens Methanomassiliicoccus, Methanospirillum, and Methanobacterium, aiding in the removal of phenolic compounds. The study suggests that an HRT of 72h is optimal for maximizing CH₄ production in the EGSB reactor.

Application of Agro-industrial Solid Waste as Biochar for Iron (II) Removal from Aqueous Solution

In recent years, various industrial activities have introduced a high concentration of iron in the waterbody which causes serious problem to environment. This paper proposed the application of Exhausted Coffee Husk (ECH) as the biosorbent (BS) for removing iron (Fe) (II) in the aqueous solution. The ECH was carbonized into biochar before performing biosorption of the heavy metal ion. The effect of carbonization temperature, time and rate on the performance of the ECH biochar for removing Fe (II) were evaluated. The percentage of removal efficiency (RE) and the capacity of biosorption (mg/g) were considered as the determining parameters. The pyrolysis temperature was varied in a range of 200-600 °C with 50 °C of interval, while the time was in between 1h – 3h with a n interval of 0.5 h, and the temperature gradient of 5 – 25°C/min. The results showed that the temperature had a significant effect on the properties of the ECH biochar as BS for Fe (II). The temperature of 550 °C, at 1.5 h of time and 25 °C/min was chosen as the suggested carbonization temperature of biochar from ECH for biosorption of Fe (II). Keywords: Agro-industrial solid waste, Biosorption, Carbonization, Exhausted coffee husk (ECH), Heavy metal.

Reactivation of used bentonite (Spent Bleaching Earth) and its reuse as adsorbent for CPO (Crude Palm Oil) bleaching process

Used bentonite or spent bleaching earth (SBE) is one of agro-industrial solid wastes in palm oil bleaching process. SBE has potential to be reactivated and reuse as adsorbent of crude palm oil (CPO). Reusing reactivated SBE is an effort to utilize waste so that it can increase added value while also preventing environmental damage due to waste accumulation. This study aimed to determine the effect of repeated use of reactivated SBE as adsorbent in the CPO bleaching process. The research methods consisted of 4 stages: characterization, reactivation of SBE and CPO bleaching process, then analysis of bleached oil, and cost analysis of the process. This study used two different types of SBE whose oil content had previously been recovered. Repetitive use of both SBE samples affected the quality of bleached oil. Maximum repetitive use that could be received by using SBE samples A was at fourth level and B was at the second level. Costs analysis of reactivation and two times repeated use of SBE was higher than fresh bleaching earth (FBE) purchase with equivalent amount for bleaching process. However, reactivation and reuse of SBE could increase the added value of the waste and prevent negative impacts on the environment.

Microbial Astaxanthin Production from Agro-Industrial Wastes—Raw Materials, Processes, and Quality

The antioxidant and food pigment astaxanthin (AX) can be produced by several microorganisms, in auto- or heterotrophic conditions. Regardless of the organism, AX concentrations in culture media are low, typically about 10–40 mg/L. Therefore, large amounts of nutrients and water are necessary to prepare culture media. Using low-cost substrates such as agro-industrial solid and liquid wastes is desirable for cost reduction. This opens up the opportunity of coupling AX production to other existing processes, taking advantage of available residues or co-products in a biorefinery approach. Indeed, the scientific literature shows that many attempts are being made to produce AX from residues. However, this brings challenges regarding raw material variability, process conditions, product titers, and downstream processing. This text overviews nutritional requirements and suitable culture media for producing AX-rich biomass: production and productivity ranges, residue pretreatment, and how the selected microorganism and culture media combinations affect further biomass production and quality. State-of-the-art technology indicates that, while H. pluvialis will remain an important source of AX, X. dendrorhous may be used in novel processes using residues.

Fungal biopesticide production: Process scale-up and sequential batch mode operation with Trichoderma harzianum using agro-industrial solid wastes of different biodegradability

This work presents a sequential batch operational strategy (SBR) for fungal conidia production in solid-state fermentation (SSF) to improve the traditional batch operation, while also aiming to present a robust and scalable process. Trichoderma harzianum was fermented using two substrates with different biodegradability (rice husk and beer draff), scaling from 1.5 L to 22 L bioreactors. Before the SBR operation, the optimum time to get inoculum from each SBR batch was determined as 4 days. While single batch process scale-up was successful with both substrates, SBR strategy was only feasible using beer draff as substrate: conidia production was sustained during 3 consecutive batches in 1.5 L bioreactors and for 5 batches at 22 L. At both scales conidia production was around 2.0x109 conidia g-1dm, achieving maximum specific oxygen consumption rate (sOUR) values close to 4 g O2 kg-1dm h-1 in most reactors. Air filled porosity was found as a key parameter regarding process scale-up, with a minimum value of 80% as necessary to proper scaling up to 22 L. Process robustness was statistically demonstrated as no significant differences in conidia production, moisture and pH were found at different reactor heights using both substrates in most 22 L reactors tests. Consequently, SBR operation has been presented as a reproducible method to overcome traditional packed-bed drawbacks while also improving SSF performance in comparison to traditional industrial SSF processes.

Application of helium-neon red laser for increasing biohydrogen production from anaerobic digestion of biowastes

Biohydrogen has significant feasibility since biological processes are much less energy intensive compared with electrolysis and thermo-chemical processes. It is widely recognized that considerable amounts of hydrogen (H2) can be produced from renewable resources without using energy from fossil fuels. Biological processes and bacterial fermentation are considered as the most environmentally friendly alternatives for satisfying future hydrogen demand. Biohydrogen production from agricultural and agro-industrial solid waste and wastewater is considered as highly advantageous as materials of this kind are abundant, cheap and biodegradable. The combustion of H2 with oxygen produces water as its only product: Unlike other fuels, the combustion of H2 does not produce carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), hydrocarbons or particulate matter (PM). Therefore, hydrogen is an environmentally friendly fuel where endeavors focus on producing specially designed internal combustion engines that can use H2 as fuel. The results showed that laser irradiated inoculum increased biohydrogen production by 1.2 times of the control. Therefore, in this research, it was hypothesized that exposing purple non-sulfur bacterial (PNSB) mix consortium to Helium-Neon red laser for 2 hours increased cell activity and consequently the biohydrogen production from food wastes through photo-fermentation process.

Silica-based adsorbent material with grape bagasse encapsulated by the sol-gel method for the adsorption of Basic Blue 41 dye

Grape bagasse is an agro-industrial solid waste produced in large quantities representing an environmental issue for wineries. An organic-inorganic hybrid material was obtained by the acid catalyzed sol-gel route in the presence of grape bagasse for application as dye adsorbent. Analysis by FT-IR has shown the main bands related to cellulose, hemicellulose and lignin of the grape bagasse structure and the peaks related to the silica fingerprint region. Zeta potential measurements demonstrated that the hybrid material based on grape bagasse is anionic in a wide range of pH value (2.0–12.0) that favors the adsorption of cationic contaminants. XRD pattern shown amorphous structure that is adequate for adsorption of large molecules as dyes. Then, the effect of pH (3.0–12.0), adsorbent concentration (0.5–5.0 g L−1), and the kinetic of Basic Blue 41 (cationic azo-dye) adsorption onto the hybrid material based on grape bagasse were investigated at various temperatures. The optimal conditions for the dye adsorption were established at pH 6.0 and adsorbent concentration of 5.0 g L−1. The kinetic data were best fitted to the pseudo-second order kinetic model. The maximum monolayer adsorption capacity achieved was 268.1 mg g−1 at 313 K.

Macro-TGA steam-assisted gasification of lignocellulosic wastes

The kinetics of the steam-assisted gasification for three different agro-industrial solid wastes (sawdust, olive and plum pits) was studied by macro thermo-gravimetric analysis (macro-TGA) at different heating rates (5, 10 and 15 K/min). The progressive CO release was moreover monitored to fully identify each step of the global gasification process. A single-step kinetics modelling was applied by using the Coats-Redfern method, with both a first order model for pyrolysis and a Ginstling - Brounstein 3D-diffusion model for the gasification stages, respectively. A comparison between macro-TGA and previous TGA results for the same bio-wastes was performed. Results indicated that the reaction proceeds in three well-defined and subsequent stages, involving water evaporation [298–473 K], biomass de-volatilization [473–648 K] with the highest production of CO, and char gasification as final step. Reaction rate parameters of the Arrhenius equation were determined for both the pyrolysis and gasification steps.

Effects of Various Agroindustrial Wastes on Nutrition Yield and Quality of Canola (Brassica napus L.)

Introduction:Canola is an important agricultural crop generally grown for oil and biofuel generation.Materials and Methods:The agroindustrial solid wastes of oregano and cumin wastes were used in a vegetation experiment to determine their effect on the nutrition, yield and quality of the canola plant (Brassica napusL.) The experiment was performed on 12 plots of 6 m2and was conducted with four treatments of composted oregano and cumin wastes, mineral fertilization and control in three replications. Physical and chemical properties and macro-micro nutrients were determined in the soils at the beginning and the end of the experiment.Results and Discussion:The leaves showed sufficient levels of N, P, K, Ca, Mg and low sufficient levels of Na, Fe, Cu, Zn and Mn. The boron content of the leaves was insufficient. Manganese and B were affected significantly by the applications. The applications did not affect plant height, shoot and carob number per plant, and seed numbers per carob significantly. Statistically, the highest number of plants per m2was observed in the plots to which cumin wastes were applied, and these plots also showed the maximum yield.Conclusion:Seed yield, protein and oil percentages were not affected significantly by the applications.

Evaluation of Croatian agricultural solid biomass energy potential

Agricultural solid biomass has been widely recognized as an important source of renewable energy with huge production potential. The utilisation of agricultural solid biomass as feedstock for energy production is continuously growing all over Europe. As shown in the current country's balance of energy production and consumption, Croatia is highly dependent on imported fossil fuels. The aim of this paper is to determine the available agricultural solid biomass and its energy potential in Croatia. The quantity and energy potential of solid biomass refer to post-harvest residues, pruning residues, agro-industrial solid waste and biomass from Miscanthus energy crop. In relation to potentially available agricultural biomass, three scenarios have been developed (progressive – S1, optimistic - S2, and conservative – S3) of introducing solid biomass in the renewable energy production sector. On the basis of these scenarios, it can be concluded that in Croatia the following quantities of agricultural biomass are available: 3050.3 t (S1); 1441.8 t (S2); and 733.68 t (S3). These quantities give energy potential of 51.14 PJ (S1), 24.06 PJ (S2), and 12.18 PJ (S3) respectively.

Effect of ultrasound pre-treatment on the physicochemical composition of Agave durangensis leaves and potential enzyme production

Approximately 1 million tons of agave plants are processed annually by the Mexican tequila and mezcal industry, generating vast amounts of agroindustrial solid waste. This type of lignocellulosic biomass is considered to be agroindustrial residue, which can be used to produce enzymes, giving it added value. However, the structure of lignocellulosic biomass makes it highly recalcitrant, and results in relatively low yield when used in its native form. The aim of this study was to investigate an effective pre-treatment method for the production of commercially important hydrolytic enzymes. In this work, the physical and chemical modification of Agave durangensis leaves was analysed using ultrasound and high temperature as pre-treatments, and production of enzymes was evaluated. The pre-treatments resulted in modification of the lignocellulosic structure and composition; the ultrasound pre-treatment improved the production of inulinase by 4 U/mg and cellulase by 0.297 U/mg, and thermal pre-treatment improved β-fructofuranosidase by 30 U/mg.

Isolation of organic compounds with high added values from agro-industrial solid wastes

Phenols are organic compounds with high antioxidant activity. Occurring mainly in plants, where they act as pigments or even as part of defense mechanisms against insects and herbivores. Given the positive impact on on human health, their isolation and purification from agricultural products is of particular interest for the production of nutritional, pharmaceutical and cosmetics supplements. In our study different materials rich in phenolic compounds were used, in order to separate the phenolic content and maximum condensation using physicochemical methods such as solvent extraction, filtration through membranes, adsorption/desorption on resins and vacuum distillation. The materials tested were solid wastes from winery, cocoa residuals, olive leaves, etc. The first step for the treatment was the extraction of phenolic content using water-ethanol solutions which was initially optimized. Then, sequential membrane filtration of the extracts by Ultrafiltration membranes, Nanofiltration and Reverse Osmosis was performed to separate the contained compounds, based on their molecular weight. To remove non-polar compounds, with similar molecular weights with phenols, methods of adsorption/desorption on specific resins were developed, in order final ethanolic solutions rich in phenolic compounds to be obtained. Finally, the ethanol was removed by vacuum evaporation at low temperatures. The purification of olive leaf phenols is illustrated in details in the present work. The final obtained concentrate, was a rich phenolic concentrate and contained 98 g/L phenols in gallic acid equivalents. This technique, after modification, can be applied to a variety of phenol-rich byproducts, allowing the operation of phenol separation plant adjustable to local agricultural activities.

Composting as a cleaner strategy to broiler agro-industrial wastes: Selecting carbon source to optimize the process and improve the quality of the final compost

The growth of broiler meat production chain in Brazil has resulted in a strong increase in the wastes produced either at the pre-finishing stages (reproductive poultry litter and hatchery waste) or during finishing and meat processing (floatation sludge, sausage casings, and charcoal waste). These wastes are produced in high amount, mainly the floatation sludge which presents a low C:N ratio. Composting is the primary available stabilization process for broiler agro-industrial solid wastes in Brazil, but these high-nitrogen wastes must be combined with a compatible carbon source to accelerate the process and to produce high quality compost. In this study, five regional materials—cotton fiber waste, urban tree trimmings, sawdust, milled sugarcane bagasse and ground Napier grass—were assessed as potential carbon sources to improve composting of broiler agro-industrial solid wastes. Analyzed variables associated with composting area optimization included composting time and the reduction in dry matter weight and volume. Analyzed variables that reflected the quality of the final compost included electrical conductivity, germination index, concentrations of N, P and K, C:N and humic to fulvic acid ratios. Multivariate analysis, including cluster and principal component analyses, indicated that cotton fiber waste, as a carbon source, optimized composting area utilization and resulted in finished compost with high agronomic value. However, due to its high level of nutrients, cotton fiber waste showed the highest EC, which limits its use as seedling substrate.

Sawdust waste as a low-cost support-substrate for laccases production and adsorbent for azo dyes decolorization.

BackgroundLaccases are multicopper oxidases with high potential for environmental and industrial applications. Low-cost laccase production could be achieved by solid state fermentation on agro-industrial by-products.MethodsA number of agro-industrial solid wastes were tested as support-substrate for laccase production by Coriolopsis gallica under solid-state fermentation (SSF) conditions. Response surface methodology (RSM) was used to optimize the medium composition for laccase production. Initial screening by Plackett-Burman design was performed to select the major variables out of 20 tow medium components fellowing this Central composite design (CCD) was employed to optimize the level of the selected variables.ResultsSawdust waste was shown to be the best support-substrate for laccase production by the C. gallica. Peptone as source of organic nitrogen, Cd2+ as laccase inducer and liquid/solid (L/S) ratio were found to have significant effects on laccase production. Operating at optimum concentrations of the most significant variables (peptone, 4.5 g L−1, L/S ratio, 5.0 and Cd+2 1.0 mM) extracellular laccase activity was enhanced from 1480 U L−1 (60.5 U g−1), to 4880 U L−1 (200 U g−1) which meant a 3.2-fold increase in laccase activity. On the other hand, sawdust waste was studied as a low cost adsorbent to remove the azo dyes Reactive Black 5 (RB5) and Acid Orange 51 (AO51). Decolorization percentages around 67 and 75 % were obtained in 24 h for RB5 and AO51, respectively.ConclusionWhen used as a support substrate, sawdust yielded the highest laccase production which was increased 3.2 times using RMS optimization.

Tree or Shrub Jatropha curcas L.: Biofuel and Potential Herb

An attempt was made to update on review available literature on unique and potential herb of Jatropha curcas L. (Jatropha) for augmenting renewable energy source, genetic improvement and production of biodiesel from seed oil. Jatropha. curcas has spread beyond its original distribution because of its low moisture demands, pure hardiness, easy propagation, drought endurance, high oil content, low seed cost, short gestation period, rapid growth, adoption to wide agro-climatic condition, bushy/shrubby nature, tangible and intangible benefits of ecology and environment and it also used as a multifunctional plant for traditional medicine, bio-pesticide, land erosion control, live hedge, oil for lighting and soap making as well as alternative energy sources because it is non-toxic and biodegradable. Due to the concern on the availability of recoverable fossil fuel reserves and the environmental problems caused by the use those fossilfuels, considerableattention has been given to biodiesel production as an alternative to petrodiesel. Indeed, various important roles of Jatropha such as its application, extension, agroforestry systems, carbon sequestration, medicinal properties, agro-industrial solid waste, bio-fuels and by products, income and risks, which needs to be exploited well for its beneficial role in tropical environment. These issues are dealt herewith to observe its future scope to mitigate energy crisis, environmental management and sustainable productions.

Recycling of agroindustrial solid wastes as additives in brick manufacturing for development of sustainable construction materials

Accumulation of unmanaged agroindustrial solid wastes especially in developing countries has resulted in an increased environmental concern. Recycling of such wastes as a sustainable construction material appears to be a viable solution not only to the pollution problem but also an economical option to design green buildings. This paper studies the application of several agroindustrial wastes in brick manufacturing, which include cocoa shell, sawdust, rice husk and sugarcane. First, the mineralogical and chemical composition of the wastes and clayey soil were determined. Next, bricks were fabricated with different quantities of waste (5%, 10% and 20%). The effect of adding these wastes on the technological behavior of the brick was assessed by compressive strength, flexural strength and durability tests. Based on the results obtained, the optimum amounts of agroindustrial waste to obtain bricks were mixing 10% of cocoa shell and 90% of clayey soil. These percentages produced bricks whose mechanical properties were suitable for use as secondary raw materials in the brick production.

Structural properties of beds packed with agro-industrial solid by-products applicable for solid-state fermentation: Experimental data and effects on process performance

Abstract The knowledge of structural properties of beds packed with particles from agro-industrial solid wastes is important for modeling and simulation of heat and mass transfer in solid-state fermentation (SSF) in packed-bed bioreactors. This paper addresses the experimental determination of particle and bulk densities (ρpart and ρbulk) and porosities (e) of beds packed with sugar cane bagasse (SCB), wheat bran (WB) and orange pulp and peel (OPP) and with mixtures of them. The effects of moisture content (MC) and packing technique on structural properties were evaluated. Microscopic analysis of cell-size was performed and the porosity along the fermentation was determined, as well as the endoglucanase yields for different proportions of a medium composed by SCB/WB. Results showed that MC affects significantly ρpart, ρbulk and e. For OPP and WB, e ranged from 0.4 to 0.7, depending on MC, and for SCB from 0.7 to 0.9, depending on MC and packing technique. For the composed media SCB:OPP:WB (1:2:2, weight) and SCB:WB (7:3), e values were similar to the ones obtained for SCB. The growth of the fungi Myceliophthora thermophila I-1D3b and Trichoderma reesei QM9414 did not affect e of the medium composed by SCB:WB. A comprehensive discussion on how the structural properties of solid matrices affect the performance of SSF processes was done, considering both operational aspects and bioproducts yields.

A route from olive oil production to natural dyeing: valorisation of prina (crude olive cake) as a novel dye source

An attempt has been made to valorise an agroindustrial solid waste in natural textile dyeing as a novel dye source. The dyeing and fastness properties of prina (crude olive cake/pomace) extract were evaluated to fill the gap in this field. This very cheap biomass was utilised (80 g/l) by applying chemical solvent‐free aqueous extraction to dye wool fabric with only small amounts (0.2, 0.4, 0.8, and 1.6 g/l) of metallic mordants, namely alum, iron(II) sulfate, copper(II) sulfate, stannous chloride, and potassium dichromate, and avoiding the use of alkali, acid, chemicals, and auxiliaries in dyeing and washing processes. Colour shades of beige, cream, sandy, apricot, straw, cumin, mustard, olive, and khaki were obtained. Significant differences in colour strength and CIELab coordinates were observed, depending on mordant type and mordanting method. Copper(II) sulfate and iron(II) sulfate ensured the most significant colour changes and nuances, the darkest colours, and the best light fastness values. Prina extract itself (without mordant) has a light fastness of 3 (fair) and excellent wash fastness of 4–5, both for colour change and bleeding. Irrespective of the concentration and mordanting method, alum, stannous chloride, and potassium dichromate did not generate a light fastness improvement compared with the control sample. Although good light and wash fastness values have been achieved without mordants, it is necessary to use them to widen the colour gamut and to obtain increased colour strength.

Zinc chloride-activated jatropha husk carbon for removal of phenol from water by adsorption: equilibrium and kinetic studies

Jatropha curcas is an important plant for production of bio-diesel. Jatropha husk, an agro-industrial solid waste, is used for the production of carbon activated by treatment with zinc chloride (ZnCl2-activated jatropha husk carbon, ZAJHC); the obtained material is applied to adsorb phenol from wastewater. Adsorption kinetics are of second order. Adsorption equilibrium data are analyzed using Langmuir, Freundlich, and D–R isotherm models for phenol concentrations of 20–100 mg L−1. Langmuir adsorption capacity was found to be 49 mg g−1. X-ray diffraction and scanning electron microscopy analyses provide essential details about the surface of ZAJHC.

Optimization and characterization of a new lipopeptide biosurfactant produced by marine Brevibacterium aureum MSA13 in solid state culture

The biosurfactant production of a marine actinobacterium Brevibacterium aureum MSA13 was optimized using industrial and agro-industrial solid waste residues as substrates in solid state culture (SSC). Based on the optimization experiments, the biosurfactant production by MSA13 was increased to threefold over the original isolate under SSC conditions with pre-treated molasses as substrate and olive oil, acrylamide, FeCl 3 and inoculums size as critical control factors. The strain B. aureum MSA13 produced a new lipopeptide biosurfactant with a hydrophobic moiety of octadecanoic acid methyl ester and a peptide part predicted as a short sequence of four amino acids including pro-leu-gly-gly. The biosurfactant produced by the marine actinobacterium MSA13 can be used for the microbially enhanced oil recovery processes in the marine environments.