Organic Solid Waste Research Articles

Carbon fixation mechanism of fungal community bypass strategy in rice straw composting combined with functional microbes: inhibition from cellobiose to glucose pathway

Composting offers an eco-friendly approach, converting organic solid waste into valuable soil enhancer products. Three experimental treatments were designed to explore the microbial mechanisms influencing lignocellulose loss in rice straw composting: CK (the control), B4 (inoculated with Bacillus subtilis), and Z1 (inoculated with Aspergillus fumigatus). The results showed significant increases in carboxymethyl cellulase, cellobiohydrolase, laccase, and xylanase activities during B4 and Z1composting. However, lignin peroxidase and manganese peroxidase were not significantly affected, and β-glucosidase was inhibited. Additionally, microbial inoculation stimulated lignin loss, with B4 and Z1 composting increasing degradation by 14.42% and 16.29%, respectively, compared to the CK. Simultaneously, humic substance content increased as microbial inoculation inhibited β-glucosidase, causing cellobiose to accumulate and divert into a pathway that forms humic substances. The random forest model showed that Symmetrospora and Phaeosphaeria significantly boosted lignocellulose loss in B4 and Z1 composting by promoting fungi functional aggregation, thus accelerating the degradation and transformation process. This study explored the microbial mechanism of lignocellulose loss and provided new insights into lignocellulose conversion and carbon fixation.

Growth Response of Cucumber in Different Solid Organic Waste Materials

The study aims to investigate the effect of various organic waste materials on the growth of cucumber plants. The study is motivated by the increasing need for sustainable agricultural practices and the potential use of organic waste as a source of nutrients for plant growth. The experiment will be conducted using a randomized complete block design with three treatments: food scraps, animal manure, yard waste. Cucumber seeds will be sown in pots filled with soil mixed with the respective organic waste material. The growth parameters such as plant height and length of leaves will be measured at regular intervals. It is hypothesized that cucumber plants grown in soil amended with organic waste materials will exhibit better growth compared to those with no fertilizer. This hypothesis is based on previous studies that have shown the positive impact of organic waste on plant growth due to its nutrient content. The results obtained from this research will contribute to our understanding of the potential use of different organic waste materials as a sustainable alternative to synthetic fertilizers in agriculture. It may also provide insights into effective methods for recycling and managing organic waste for agricultural purposes.

A Review on Composting of Organic Solid Waste

A Review on Composting of Organic Solid Waste

Solar-Driven Biomass Reforming for Hydrogen Generation: Principles, Advances, and Challenges.

Hydrogen (H2) has emerged as a clean and versatile energy carrier to power a carbon-neutral economy for the post-fossil era. Hydrogen generation from low-cost and renewable biomass by virtually inexhaustible solar energy presents an innovative strategy to process organic solid waste, combat the energy crisis, and achieve carbon neutrality. Herein, the progress and breakthroughs in solar-powered H2 production from biomass are reviewed. The basic principles of solar-driven H2 generation from biomass are first introduced for a better understanding of the reaction mechanism. Next, the merits and shortcomings of various semiconductors and cocatalysts are summarized, and the strategies for addressing the related issues are also elaborated. Then, various bio-based feedstocks for solar-driven H2 production are reviewed with an emphasis on the effect of photocatalysts and catalytic systems on performance. Of note, the concurrent generation of value-added chemicals from biomass reforming is emphasized as well. Meanwhile, the emerging photo-thermal coupling strategy that shows a grand prospect for maximally utilizing the entire solar energy spectrum is also discussed. Further, the direct utilization of hydrogen from biomass as a green reductant for producing value-added chemicals via organic reactions is also highlighted. Finally, the challenges and perspectives of photoreforming biomass toward hydrogen are envisioned.

Generation and persistency of combustion-derived environmentally persistent free radicals from phenolic compounds over a Fe2O3/SiO2 surface

Combustion of organic solid wastes releases phenolic compounds which can act as precursors in the formation of environmentally persistent free radicals (EPFRs) in the post-flame, cooling zone of waste combustion. The study investigated the generation mechanism of EPFRs from phenolic compounds catalyzed by transition metals in air atmosphere under simulated combustion conditions. Representative combustion-derived phenolic compounds were used, and SiO2 particulates containing different mass ratio of Fe2O3 were synthesized as carriers. EPFRs formed had g-factors between 1.9998 and 2.0066, indicating phenoxyl-, cyclopentadienyl-, and semiquinone-type radicals, along with paramagnetic F-centers. The promotion effect of phenolic compounds on EPFR formation during heating decreased as catechol > hydroquinone > phenol > p-cresol. This trend is related to hydroxyl groups and activation energy. In particular, catechol chemically adsorbed on Fe2O3 at 600 K led to the formation of EPFRs with relatively high spin concentrations (up to 1.28 × 1017 spin/g). Higher Fe2O3 concentrations promoted the transformation of phenoxyl-type radicals into cyclopentadienyl-type and paramagnetic F-centers. However, as the Fe2O3 loading increased from 1.25% to 5%, the density of EPFRs decreased. The findings related to the influence of various precursors and Fe2O3 concentration on EPFR formation provide valuable insights for estimating EPFR generation and associated risk during combustion processes.

PEMANFAATAN TERATAI PUTIH SEBAGAI BAHAN BAKU PEMBUATAN SELULOSA MIKROKRISTALIN MENGGUNAKAN HIDROLISIS ENZIMATIK DARI RAYAP Coptotermes sp.

Microcrystalline cellulose is still imported by the Pharmaceutical Industry in Indonesia even though Indonesia has large natural resources but they have not been utilized optimally. Microcrystalline cellulose can be obtained from residue (extraction dregs) in the lotus plant extraction process, namely in the form of simplicia powder which will not be used again (organic solid waste). This research aims to obtain microcrystalline cellulose from several parts of the white lotus plant (Nymphaea nouchali Burm. F.) using the enzymatic hydrolysis method using cellulase from the termite Coptotermes sp., then the quality of the powder will be tested and compared with Avicel PH 101. Each part The white lotus is extracted, then the residue is delignified to obtain α-cellulose, then hydrolyzed with crude extract from Coptotermes sp termite cellulase. so that microcrystalline cellulose is obtained which will then be characterized and compared with the commercial version, namely Avicel® PH 101. The highest yield of microcrystalline cellulose is found in leaves with a yield of 95.3%, followed by leaf stalks 89.3%, flower stalks 75.7%, and the yield lowest in interest with a percentage of 74%. The physical characteristics in the form of color reaction, organoleptics, solubility and pH of white lotus microcrystalline cellulose powder show similarities with the comparison standard. It can be concluded that microcrystalline cellulose powder from several parts of the white lotus plant can be an alternative in obtaining cellulose raw materials from natural sources.

Análise da eficiência de compostagem e vermicompostagem para resíduos sólidos orgânicos com inserção de material biodegradável

Improper disposal of solid waste leads to environmental and socioeconomic damages. In Brazil, approximately 45.3% of urban solid waste destined for landfills and "dumpsites" consists of organic waste, resulting in a reduced lifespan of sanitary landfills. This study aimed to analyze the efficiency of composting and vermicomposting processes for organic waste with the addition of biodegradable material. Composters were monitored for 100 days, analyzing physicochemical parameters such as temperature, pH, moisture, and organic matter. Microbial activity was also monitored through analysis of compost basal respiration, microbial biomass carbon, and metabolic quotient. Throughout the research, it was observed that temperature exhibited similar behavior during composting and vermicomposting. At the end of the process, composting pH showed better results; however, vermicomposting yielded more satisfactory results in terms of moisture and organic matter content. Microbial activity remained active, showing expected results, with a decrease in basal respiration rates and microbial biomass carbon, along with an increase in the metabolic quotient. After the study, it was concluded that the addition of biodegradable material did not interfere with the processes, demonstrating compostability potential. Thus, it was possible to ascertain that composting and vermicomposting techniques for organic solid waste, combined with the use of biodegradable material, contribute to the valorization of the circular economy, providing improvements for urban environmental sustainability.

Anaerobic digestion or composting? Small-scale plants design and holistic evaluations in a Sub-Saharan African context

In small developing settings, is it worth building anaerobic digestion (AD) or composting plants? This study explores the economic, management, and environmental dimensions of two small-scale alternatives for organic fraction municipal solid waste (OFMSW) treatment within the context of Lacor Hospital (Uganda): aerated static pile composting (S1) and AD with digestate composting (S2), both designed to manage approximately 347.5 tOFMSW annually. In the optimistic scenario, S1 achieves a cost savings of about −2.9 USD tOFMSW−1, while S2 incurs costs of 2.1 USD tOFMSW−1. In the pessimistic scenario, S1's costs rise to 3.9 USD tOFMSW−1, while S2 becomes more expensive at 9.5 USD tOFMSW−1. Management analysis underlines S2's complexity due to AD operations and digestate drying. Total normalized environmental impacts of S1 can be quantified with about 0.125 mPt tOFMSW−1, whereas S2 is equal to about −6.163 mPt tOFMSW−1. However, in an optimistic scenario, climate change endpoint category results are similar. On balance, the LCA analysis indicates that AD can be better than standalone composting. However, in developing settings serving approximately 3000 inhabitants, it is crucial to prioritize economic and management sustainability that can be obtained only by small-scale composting plants. These findings provide definite insights for small-scale waste management projects in low-income regions, offering valuable data and references for plant design and their replicability. The study sets the ultimate definition of the most feasible option to treat OFMSW in low-income settings: community composting. Unfortunately, economic barriers remain the main challenge: citizens should pay for the service and landfill management fees should be set by local governments.

Production and characterization of compost derived from municipal organic solid wastes

Perú generó 8.215.355 t de residuos sólidos municipales en el 2021; de este, 57,64 % corresponde a residuos orgánicos (RO) y 61,28 % son dispuestos en rellenos sanitarios con múltiples deficiencias de gestión, lo que exige buscar alternativas para tratar de manera segura los RO. Frente a esta situación, el compostaje permite la biotransformación, la reducción y la obtención de biofertilizantes, que se pueden aplicar como sustrato o enmienda. El objetivo de la investigación fue evaluar indicadores de procesamiento y calidad de compost derivado de residuos sólidos orgánicos urbanos, en Leoncio Prado, región Huánuco, Perú. Se evaluaron los tipos de residuos, basados en la normativa peruana para caracterización de residuos, los indicadores del proceso (temperatura y pH), la caracterización fisicoquímica y calidad en base a las normas internacionales. Los resultados muestran diferencia significativa para pH, nitrógeno, calcio, potasio, cobre y zinc; contrariamente, la materia orgánica, el % de cenizas, la conductividad eléctrica, el sodio y el fósforo no mostraron diferencias, siendo lo más destacado los altos niveles de pH, además, la calidad del compost es de “Clase B”, según la norma chilena 2880. Los compost producidos son de calidad media y se recomienda su uso como sustrato o enmienda en la agricultura, previo tratamiento para corregir los altos niveles de pH.

A novel bio-based film-forming helper derived from Leuconostoc mesenteroides: A promising alternative to chemicals for the preparation of biomass film

Some microorganisms produce biopolymers with adhesive, film-forming, and plant-promoting properties in their fermentation broths. These biopolymers hold significant potential as substitutes for chemical film-forming helpers in liquid mulch. The present study involved the preparation of a novel bio-based film-forming helper (BFH-L) through the process of bio-fermentation utilizing Leuconostoc mesenteroides. The successful preparation of BFH-L was confirmed through the assessment of adhesive properties and plant growth-promoting efficacy exhibited by L. mesenteroides and BFH-L. The comprehensive genomic analysis of L. mesenteroides provided compelling evidence supporting the effectiveness of BFH-L, which can be attributed to the functional contribution of genes encoding extracellular glycoside polymers from L. mesenteroides. Through the evaluation and comparison of a triangle model, BFH-L can effectively replace chemical film-forming helpers in the preparation of biomass film (BF). The optimal performance of BF was achieved when 3.0 g/600 mL of BFH-L and 30 g/600 mL of cow dung were added. BF exhibited exceptional water retention ability (water loss: 38.00 ± 3.46 %), superior plant growth promotion effect (germination rate: 100.00 ± 0 %, plant growth: 0.34 ± 0.03 g), and minimal environmental impact (pH value = 8.7). This research provides a new strategy for reducing plastic film pollution while achieving green recycling of organic solid waste from agriculture and animal husbandry.

Techno-economic and environmental analysis of organic municipal solid waste for energy production

Addressing the critical conundrum of escalating municipal solid waste (MSW) and shrinking landfill spaces in urban areas, this research pioneers a sustainable approach for Bangladesh by exploring the potential of biogas production from MSW. Distinctly, it fills the research gap by providing a detailed techno-economic and environmental analysis of decentralized fixed-dome anaerobic digestion facilities in the urban context of Chittagong, Bangladesh, a domain previously underexplored. Our findings demonstrate the feasibility of converting MSW into a renewable energy source, offering an innovative solution that simultaneously tackles waste management and energy generation challenges. Each proposed plant showcases the capability to generate 536 m³ of biogas daily, sufficient to power a 50 kW gas engine and supply 44 households, thereby contributing significantly to urban waste reduction and CO2 emissions mitigation by approximately 500 tons monthly. The economic analysis reveals an attractive investment payback period of two years, underscoring the model's viability and its potential as a replicable framework for similar urban settings grappling with waste management crises. This study not only bridges a critical knowledge gap but also introduces a novel, sustainable waste-to-energy model, marking a pivotal step towards achieving energy security and environmental sustainability in developing nations.

Recycling crayfish shell and waste activated sludge as biochar to in-situ enhance antibiotics removal from wastewater: Linking structure properties and reaction kinetics

Aquaculture water represents a substantial source of antibiotics in the environment, thereby implicating potential hazards to human health and ecological stability. Additionally, the cultivation of crayfish in such water exacerbates concerns regarding the management of shell waste. In this investigation, crayfish shells and waste activated sludge were repurposed as biochar for the in-situ mitigation of antibiotics elimination from aquaculture wastewater. Compared to crayfish biochar (C-BC) solely from crayfish shell, crayfish sludge biochar (CS-BC) significantly enhances the adsorption of typical antibiotics like tetracycline and ciprofloxacin by 50.3–77.1 %. Findings from kinetic and isotherm experiments suggest that antibiotics adsorption mainly involves physical pore filling, but sludge introduction shifts CS-BC towards chemical adsorption. Further analysis reveals that sludge introduction reduces biochar pore size, boosts specific surface area, and offers more active adsorption sites. Additionally, hydrogen bonding on hydroxyl groups and increased oxygen-containing functional groups enhanced antibiotic adsorption onto CS-BC surfaces. This research presents a promising strategy for addressing antibiotic pollution in aquatic environments while also improving the utilization of organic solid waste resources.

Knowledge graph and development hotspots of biochar as an emerging aquatic antibiotic remediator: A scientometric exploration based on VOSviewer and CiteSpace

As an emerging material in the field of environmental remediation, biochar produced by carbonisation of organic solid waste has been widely used in the remediation of antibiotic wastewater due to its environmental friendliness and excellent adsorption properties. This study analyses the current literature in the field in a comprehensive and scientific manner using CiteSpace and VOSviewer technologies. Between 2011 and 2023, a total of 1162 papers were published in this domain, spanning three distinct stages: applied methods, mechanism investigation, and enhanced improvement. The results of keyword clustering indicate that the remediation of antibiotics complexed with multiple pollutants by biochar is the main research topic, followed by the remediation of antibiotics by biochar in combination with other technologies. Furthermore, drawing from current research hotspots in antibiotic remediation using biochar, this study identified the pivotal mechanisms involved: (1) The primary mechanisms by which raw biochar remediates antibiotics include π-π electron donor-acceptor interactions, hydrophobic interactions, electrostatic interactions, hydrogen-bonding, and pore filling. (2) Steam activation, acid/base, metal salt/metal oxide, and clay mineral modification can improve the physical/chemical properties of biochar, enhancing its adsorptive removal of antibiotics. (3) Biochar activated persulfate and degraded antibiotics via free radical pathways (SO4−•, •OH and O2−•) as well as non-free radical pathways (1O2 and electron transfer). In addition, the challenge and prospect of biochar engineering applications for antibiotic remediation lies in improving the main mechanism of antibiotic remediation by biochar. The prospective utilization of biochar in enhancing the remediation of antibiotic-related pollutants holds tremendous value for the future.

Characteristics of rice husk biochar briquettes with municipal solid waste cassava, sweet potato and matooke peelings as binders

Rice husks are not readily biodegradable making their disposal challenging due to the common disposal method of open burning which has negative environmental effects. Additionally, banana, sweet potato and cassava peelings form a large percentage of organic municipal solid waste. Therefore, this study developed rice husk biochar briquettes with organic municipal peelings waste as binders. Rice husks biochar was formed via carbonization processes in a step-down kiln at temperatures ranging between 400 and 500 °C. Organic binders were mixed with the rice husk biochar at different ratios of 10% and 15% before being compacted at a pressure ≤ 7 MPa into briquettes. Thermogravimetric results showed that the developed briquettes had high ash contents ranging from 44% to 47%. Rice husk biochar briquettes with the highest particle density were observed for briquettes with 15% cassava peel binder at 427.1 kg/m3. The highest HHV and maximum attainable flame temperature of 21.75 MJ/kg and 828.7 °C were obtained for rice husk biochar briquettes with 15% matooke peeling organic binder. For all rice husk biochar briquettes, increasing the organic peeling binder had a positive impact of reducing the ash content, while at the same time increasing the peak temperatures, thus contributing to their enhanced thermal stability.

Design and optimization of a novel intestinal reactor to efficiently improve organic waste uniformity and solid content in high solid organic waste anaerobic digestion

High solid anaerobic digestion (HSAD) technology, a major treatment method for solid organic waste. Existing HSAD reactors comprise primarily vertical and horizontal reactors. Vertical reactors use high-pressure pneumatic stirring, which has high energy consumption and poor stirring performance. Horizontal reactors use long-uniaxial mechanical stirring, which occupies large land areas and has high strength requirements for stirring shaft material. In addition, during the operation of the two reactor types, the continuous liquefaction of the solid waste produces solid-liquid stratification, thus affecting mixing effects and decreasing the reactor volume rate. To solve the above problems, we designed a new simulated intestinal anaerobic digestion reactor with a natural solid-liquid separation system, short-axis mechanical stirring, and a stirring blade optimized through CFD. Use of the solid-liquid separation system increased the solid content in the reactor by 44%–55%. The operation results indicated that the homogenization of the solid waste with the optimal stirring blade was more than 50% greater than that of a conventional vertical reactor. The intestinal reactor solves the problems of poor uniformity and solid content decrease during anaerobic digestion in traditional HSAD, decreases the strength requirements for stirring shaft material, and has potential to increase urban waste treatment capacity.

Enhancing biomethanation performance through co-digestion of diverse organic wastes: a comprehensive study on substrate optimization, inoculum selection, and microbial community analysis.

A blend of organic municipal solid waste, slaughterhouse waste, fecal sludge, and landfill leachate was selected in different mixing ratios to formulate the best substrate mixture for biomethanation. Individual substrates were characterized, and the mixing ratio was optimized with the help of a response surface methodology tool to a value of 1:1:1:1 (with a C/N ratio of 28±0.769 and total volatile fatty acid (VFA) concentration of 2500±10.53 mg/L) to improve the overall biomethanation. The optimized blend (C/N ratio: 28.6, VFA: 2538 mg/L) was characterized for physicochemical, biological, and microbial properties and subjected to anaerobic digestion in lab-scale reactors of 1000 mL capacity with and without the addition of inoculum. The biogas yield of individual substrates and blends was ascertained separately. The observed cumulative biogas yield over 21 days from the non-inoculated substrates varied between 142±1.95 mL (24.6±0.3 ml/gVS) and 1974.5±21.72 mL (270.4±3.1 ml/gVS). In comparison, the addition of external inoculation at a 5% rate (w/w) of the substrate uplifted the minimum and maximum cumulative gas yield values to 203±9.9 mL (35.0±1.6 mL/gVS) and 3394±13.4 mL (315.3±1.2 mL/gVS), respectively. The inoculum procured from the Defence Research and Development Organisation (DRDO) was screened in advance, considering factors such as maximizing VFA production and consumption rate, biogas yield, and digestate quality. A similar outcome regarding biogas yield and digestate quality was observed for the equivalent blend. The cumulative gas yield increased from 2673±14.5 mL (373.7±2.2 mL/gVS) to 4284±111.02 mL (391.47±20.02 mL/gVS) over 21 days post-application of a similar dosage of DRDO inoculum. The 16S rRNA genomic analysis revealed that the predominant bacterial population belonged to the phylum Firmicutes, with the majority falling within the orders Clostridiales and Lactobacillales. Ultimately, the study advocates the potential of the blend mentioned above for biomethanation and concomitant enrichment of both biogas yield and digestate quality.

Anaerobic digestion of winery solid waste in a two-stage membrane process: Effect of loading rate on biomethane production

The wine industry causes a high amount of solid waste with high organic content at different parts of the production line. One of the best strategies to overcome organic solid waste management problem is anaerobic digestion, as It allows renewable energy production and waste reduction together. The OLR is considered one of the most important operating parameters in continuous or semi-continuous anaerobic operations, as it affects the overall performance of anaerobic digestion systems. Therefore, appropriate OLR determination plays a crucial role in anaerobic digestion. This study investigated the effect of OLR on the performance of a TAnMBR treating (winery solid waste) WSW in terms of biogas and biomethane production. To this end, the production of biogas and biomethane from WSW via a TAnMBR at four different OLRs (0.5 0.75 1.0 1.5 gVS/Lreac d) was investigated. Biogas production rates were 677, 850, 1265, and 566 ml/gVS and biomethane production rates were 352, 450, 679, and 251 ml/gVS respectively, during 0.5 0.75 1.0 1.5 gVS/Lreac d OLR operating conditions. Results revealed that proper biogas and biomethane production can continue until the OLR is 1.5. VFA accumulation can be considered as the main inhibition reason, at 1.5 OLR VFA/Alk ratio increased up to 1.6 with 1864 mgHAc/L VFA concentration. Additionally, phenol and sulfate concentrations were below 45 and 48 mg/L during operation, respectively, therefore it is considered that no inhibition occurred due to these parameters.

A novel approach to assessing the anaerobic bio-accessibility of straw using fractal dimension

Traditional methods for evaluating the bioconversion capacity of organic solid waste are known for time-consuming property and often exhibit low prediction accuracy. However, leveraging fractal dimensions offers a more precise characterization of the complexity, irregularity, and spatial structure of organic solid waste. In this study, a novel and efficient method for evaluating the bio-accessibility of straw's anaerobic transformation, based on fractal dimensions, was introduced. To comprehensively compare the structural differences, this research encompasses the measurement of nine different varieties of straw under ten distinct pretreatment conditions. The regression sum of squares for these correlations consistently exceeds 0.83, highlighting the robustness of our findings. The results unequivocally demonstrate the close relationship between the fractal dimension and the structural characteristics of straw. This relationship underscores the utility of fractal dimension analysis as a reliable tool for evaluating the anaerobic bio-accessibility of organic solid waste.

Recent advancements in harnessing biodiesel from microalgae through attached growth systems

Conventional microalgal cultivation method relied on suspended growth or attached growth that uses inert solid surfaces, requiring the addition of external carbon sources to promote microalgal growth. The inert solid substrates for attached microalgae pose constraints on the maximal capabilities of these microorganisms as it does not possess the ability to provide the necessary nutritional support required for optimal microalgal growth. As a result, microalgae are obliged to only rely on the solid substrate as a means of attachment, without any further nutritional provisions. Slower growth rates, larger resource requirements, and exorbitant operating expenses had prompted the exploration of an alternative strategy, i.e; the innovative use of solid organic waste as nutritional source cum attachment platform. The findings of this review unveil key insights into microalgae cultivation system, offering a solution to economic challenges in the production phase. This innovation not only promotes economic feasibility and sustainability, but also contributes to economically viable and environmentally sustainable biofuel production.

Design of experiments to evaluate pH and temperature parameters with different inoculums in domestic biodigester

The comprehensive management of organic urban solid waste is a concern due to its direct and indirect impact on the environment. Anaerobic Digestion (AD) has been recognized as an alternative and environmentally friendly technology for waste disposal, converting them into organic fertilizers and renewable energy. This research presents an experiment involving four reactors fed with household organic waste, three inoculated with canine, goat, and rabbit manure, and one without inoculum. The experiment was observed for 30 consecutive days to analyze the pH and temperature parameters involved in the AD process in domestic reactors. Statistical methodology, including one-way analysis of variance for assessing the effect of the type of inoculum, Tukey's simultaneous confidence intervals for mean differences, and 90 % confidence intervals for μ in temperature and manure, was utilized. Additionally, main effects analysis of the factors of average temperature and pH were conducted. The results of the one-factor experiment show that the type of inoculum does not significantly influence the variation in pH, while temperature remains relatively stable throughout the AD process. However, the analysis of main effects indicates that goat manure tends to stabilize the temperature with minimal variation, whereas variation is more heterogeneous in the other experiments.