Mature Compost Research Articles

Biodiversity and core microbiota of key-stone ecological clusters regulate compost maturity during cow-dung-driven composting

The primary objectives of this study were to explore the community-level succession of bacteria, fungi, and protists during cow-dung-driven composting and to elucidate the contribution of the biodiversity and core microbiota of key-stone microbial clusters on compost maturity. Herein, we used high-throughput sequencing, polytrophic ecological networks, and statistical models to visualize our hypothesis. The results showed significant differences in the richness, phylogenetic diversity, and community composition of bacteria, fungi, and eukaryotes at different composting stages. The ASV191 (Sphingobacterium), ASV2243 (Galibacter), ASV206 (Galibacter), and ASV62 (Firmicutes) were the core microbiota of key-stone bacterial clusters relating to compost maturity; And the ASV356 (Chytridiomycota), ASV470 (Basidiomycota), and ASV299 (Ciliophora) were the core microbiota of key-stone eukaryotic clusters relating to compost maturity based on the data of this study. Compared with the fungal taxa, the biodiversity and core microbiota of key-stone bacterial and eukaryotic clusters contributed more to compost maturity and could largely predict the change in the compost maturity. Structural equation modeling revealed that the biodiversity of total microbial communities and the biodiversity and core microbiota of the key-stone microbial clusters in the compost directly and indirectly regulated compost maturity by influencing nutrient availability (e.g., NH4+-N and NO3−-N), hemicellulose, humic acid content, and fulvic acid content, respectively. These results contribute to our understanding of the biodiversity and core microbiota of key-stone microbial clusters in compost to improve the performance and efficiency of cow-dung-driven composting.

Evolution of microbiome composition, antibiotic resistance gene loads, and nitrification during the on-farm composting of the solid fraction of pig slurry using two bulking agents

Composting is a nature-based method used to stabilize organic matter and to transform nitrogen from animal farm manure or solid fraction of slurry (SFS). The use of composted material as source of nutrients for agriculture is limited by its potential to facilitate the propagation of biological hazards like pathogens and antibiotic-resistant bacteria and their associated antibiotic-resistance genes (ARG). We show here an experimental on-farm composting (one single batch) of pig SFS, performed under realistic conditions (under dry continental Mediterranean climate) for 280 days, and using two different bulking agents (maize straw and tree pruning residues) for the initial mixtures. The observed reduction in potentially pathogenic bacteria (80–90%) and of ARG loads (60–100%) appeared to be linked to variations in the microbiome composition occurring during the first 4 months of composting, and concurrent with the reduction of water-soluble ammonium and organic matter loads. Nitrification during the composting has also been observed for both composting piles. Similar patterns have been demonstrated at small scale and the present study stresses the fact that the removal can also occur at full scale. The results suggest that adequate composition of the starting material may accelerate the composting process and improve its global performance. While the results confirm the sanitization potential of composting, they also issue a warning to limit ARG loads in soils and in animal and human gut microbiomes, as the only way to limit their presence in foodstuffs and, therefore, to reduce consumers' exposure.

Egg-laying habitat selection of the invasive slug Krynickillus melanocephalus Kaleniczenko, 1851 (Gastropoda: Eupulmonata: Agriolimacidae)

Invasive slugs cause damage to biodiversity as well as to horticultural and agricultural crops. To develop methods to mitigate problems with recently emerging invasive species, basic ecological knowledge about them in their new environment is crucial. We investigated the egg-laying substrate preference of Krynickillus melanocephalus in a laboratory experiment in which the slugs could choose between four different substrates. Slugs were mainly observed in contact with birch leaf compost, and less so with gravel, potting soil and sphagnum moss. Almost 90% of the eggs were found buried in birch leaves, although eggs were found also in the other substrates. In addition, we tested the winter survival of the eggs by examining their susceptibility to low temperatures. Eggs subjected to freezing temperatures did not survive, and at 8 °C, 60–70% of the eggs hatched after three months (640 degree days). In areas where K. melanocephalus is present, transporting any soil, gravel or compost material could potentially contribute to spreading the species. Particularly, leaf composts may warrant attention in this areas.

Changes in Nitrogen and Humus During Aerobic Composting Under Antibiotic Composite Pollution

Antibiotic residues have significantly effects on aerobic composting process. This study was targeted at antibiotic composite pollutants (e.g., sulfanilamides, tetracyclines, and quinolones) and probed into the effects of pollution levels on aerobic composting. With higher initial antibiotic concentrations, the NH4+ –N and NO3− –N concentrations at the end of composting were higher, but TN content decreased, which may be due to the inhibition effects of antibiotics on nitrogen-fixing bacteria and thus were unfavorable for nitrogen accumulation. Antibiotic pollution obviously delayed composting maturity, and the antibiotics at initial concentration above 306.12 mg/kg were significantly toxic to seeds. Analysis of structural changes in dissolved organic matter (DOM) showed the humification after treatments CK and AT100 mainly occurred at the high-temperature stage (day 2–14) and later lower-temperature maturity stage (day 21–36). Humification after treatment AT300 mainly happened at the high-temperature stage (day 2–14), and that in AT600 mainly occurred at the early temperature rise and high-temperature stage (day 2–7). This study comprehensively evaluated the effect of antibiotic composite pollution on the maturity of aerobic compost, and provided a theoretical basis for the treatment of antibiotic composite pollution materials in practical production.

CHEMICAL INNOVATIONS IN PRODUCING COMPOSTABLE CELLOPHANE MATERIALS

This article explores the chemical innovations driving the production of compostable cellophane materials. It discusses the advancements in polymer chemistry that have enabled the development of cellophane materials with enhanced compostability. The focus is on the synthesis of biodegradable polymers, the incorporation of environmentally friendly additives, and the overall impact of these innovations on the sustainability of cellophane. The article also examines the challenges in balancing compostability with material performance and the implications for the packaging industry.

Enhancing humification and microbial interactions during co-composting of pig manure and wine grape pomace: The role of biochar and Fe2O3

Phenol-rich wine grape pomace (WGP) improves the conversion of pig manure (PM) into humic acid (HA) during composting. However, the impact of using combinations of Fe2O3 and biochar known to promote compost maturation remains uncertain. This research explored the individual and combined influence of biochar and Fe2O3 during the co-composting of PM and WGP. The findings revealed that Fe2O3 boosts microbial network symbiosis (3233 links), augments the HA yield to 3.38 by promoting polysaccharide C–O stretching, and improves the germination index to 124.82 %. Limited microbial interactions, increased by biochar, resulted in a lower HA yield (2.50). However, the combination weakened the stretching of aromatics and quinones, which contribute to the formation of HA, resulting in reduced the humification to 2.73. In addition, Bacillus and Actinomadura were identified as pivotal factors affecting HA content. This study highlights Fe2O3 and biochar's roles in phenol-rich compost humification, but combined use reduces efficacy.

Morphological diversity of actinobacteria isolated from oil palm compost (Elaeis guineensis).

Composting is a natural process of decomposition of organic matter that occurs by the action of microorganisms such as fungi, bacteria, and actinobacteria. The actinobacteria are present throughout the process due to their resistance to different environmental conditions. They are Gram-positive, filamentous bacteria with a high capacity for producing secondary metabolites of biotechnological importance. Thus, the objective of this work was to isolate and characterize actinobacteria from industrial composting soil of oil palm (Elaeis guineensis) in the municipality of Igarapé-Açu, Pará. Ten samples of the material were collected and seeded on soy tryptone agar, Reasoner's 2A agar, and Columbia agar, using the serial dilution technique. For morphological characterization of the strains, Gram staining and microculture were performed, and for biochemical characterization, the motility, triple sugar iron, Simmons citrate, maltose, phenylalanine, catalase, and DNAse tests were performed. It was observed that compost actinobacteria have a great diversity in morphological and metabolic production, which may be associated with the substrate and cultivation conditions. Therefore, palm oil compost material represents a rich source of bacterial biodiversity, bringing new perspectives for the bioprospecting of actinobacteria of biotechnological importance in little explored environments.

Effectiveness of Composter with Magic Compos System Forward Reverse Design Through Temperature and Humidity Control on Composing Quality

Household waste management is an important concern in an effort to reduce the potential negative impact on public health due to organic waste generation. This study aims to analyze differences in compost maturation rates based on variations in the time interval of the turning process in Magic Compost, differences in compost maturation rates based on the type of organic waste, differences in C/N ratio, carbon content, and moisture content in compost, differences in nitrogen, phosphorus, and potassium levels in compost, and differences in temperature, pH, and color in compost based on household organic waste criteria. This research uses an experimental approach with a posttest without a control group design and applies a randomized complete group design (RAKL). The tool used is Magic Compost, which is equipped with a temperature and humidity controller. The results showed a significant difference in the rate of compost maturation based on the time interval variation of the turning process on Magic Compost (p value = 0.000). The best turning time interval is 12 hours. There was a difference in the rate of compost maturation based on the type of organic waste generated by households, with mixed waste compost maturing the fastest and rice/starch waste maturing the slowest (p value = 0.001). While there was no difference in the C/N ratio (p value = 0.202), there were significant differences in the carbon content and moisture content of the compost based on the type of organic waste (p values = 0.042 and 0.000). However, there was no difference in the nitrogen and phosphorus content of the compost (p value = 0.144 and p value = 0.663). There was a difference in potassium levels in the compost based on the type of organic waste (p value = 0.000). The temperature of the resulting compost showed no significant difference (p value = 0.000), but there were differences in the pH and color of the compost based on household organic waste criteria (p values = 0.048 and 0.007). This study provides important insights into organic waste management through composting with Magic Compost, which can be an effective solution for reducing the negative public health and environmental impacts caused by organic waste generation.

The Effect of Compost Type, Application Rate, and Maturity on Nutrient Leaching and Soil Nutrient Levels

ABSTRACT The application of compost to agricultural soils can increase nutrient leaching, causing several environmental problems. Conversely, proper management of compost application can reduce environmental risks. Agronomical trials were conducted in greenhouses in Morocco to compare the effects of varying compost application rates, types, and maturity, as well as the number of growing days, on nutrient availability and nitrate leaching in a loamy sandy soil. Additionally, the study examined the impacts of these factors on soil physical and chemical characteristics. The compost used in this study was derived from a combination of two cost-effective materials, municipal waste, and poultry manure. Tomato plants were cultivated in pots amended with compost over a period of 65 days. The soils were treated with eight composts (plus a control) obtained from municipal solid waste (MSW) mixed with poultry manure (PM) at two ratios, 3:2 and 2:3 weight weight−1 (ww−1) (C1 and C2, respectively), used at two different ages (105 days and 173 days) and at two doses (32.5 g pot−1 and 65 g pot−1, equivalent to 40 Mg ha−1 and 80 Mg ha−1). Two simulated leaching events (the first after planting and the second at harvest) were performed. The concentration of chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) in leachate varied with the number of growing days and increased in the leachate of the non-amended soil after planting. At both sampling times, compost C1, aged 173 days (d), significantly decreased COD in the leachate compared to compost C1 aged 105 d. Compost increased nitrate leaching compared with the non-amended soil. Nitrogen leaching was primarily in the form of nitrate, ranging from 61% to 78% over the whole experimental period. Compost also decreased leachate concentrations of iron (Fe) and chromium (Cr), for other metals, such as cobalt (Co) and nickel (Ni), values were very low. Moreover, compost increased total organic carbon by up to twofold at both sampling times, with the most substantial increase observed with a dose of 65 g pot−1 of compost C2 (aged 105 days). Most compost treatments also increased available phosphorus (P), inorganic nitrogen (N), total nitrogen (TNK), cation exchange capacity (CEC), and electrical conductivity (EC) at both sampling times but had no effect on pH. The metal content in the soil exhibited a decrease compared to the control soil. Overall, our study suggests that nitrogen leaching can be reduced by optimizing compost rates, properties, and stability to synchronize with crop needs.

Contact parameters calibration of mixtures in different aerobic composting period: Focusing on establishment of particle model and its flow properties

In order to calibrate the contact parameters, particle models for mixtures of each period were established by simulation of repose angle using combined models in EDEM software, and then the flow properties of mixtures in different aerobic composting periods were clarified. Results showed that compared with the six-sphere model, the use of the double-sphere model to represent the compost mixtures of each period was not only closer to the ellipsoid of the actual particles but also simplified the calculation process. The contact parameters that mostly affected the repose angle were Poisson's ratio and shear modulus of mixture in the mesophilic period and JKR surface energy in thermophilic and cooling periods. The relative errors between the simulated repose angle using the optimal parameter combination and the actual measured value were less than 2.5% indicating the reliability of the regression models at each period representing the relationship among the repose angle and significant contact parameters. In addition, the flow properties of mixtures at the mesophilic period were better than those at the thermophilic and the cooling period of its smaller repose angle, the larger mass transformation, and the smaller Ek max value. Meanwhile, mixtures in thermophilic and cooling periods had similar flow properties. Hence, these could provide information for the further application of simulation to optimize the composting process (e.g., stirring frequency and ventilation time) to promote compost maturity.

Humification and fungal community succession during pig manure composting: Membrane covering and mature compost addition

The objective of this study was to elucidate the combined effect of a semi-permeable membrane (M) and mature compost (MC) on humification and fungal community succession in pig manure composting. Compared with the control, the concentrations of humic substances (HSs) increased by 44.54 % (M + 15 % MC) and 43.90 % (M). During the thermophilic phase, Aspergillus (67.26 %) was the dominant genus in the M + 15 % MC treatment. Membrane covering increased the relative abundance (RA) of other phyla (except for Ascomycetes and Basidiomycetes) on the 14th day and Basidiomycetes on the 80th day in M treatment. Humic acid, HSs were positively correlated with the RA of genera Myceliophthora, Kernia, and Mycothermus. Myceliophthora was the key genus in the M + 15 % MC treatment on the 80th day. The results showed that 15 % MC addition under membrane covering optimizes the quality of composting products.

Mathematical modeling of biochar's role in elevating co-composted poultry carcass temperatures

Previous studies reported that incorporating biochar into composting systems leads to an increase in compost temperatures. Although potential reasons, such as improved microbial activity or increased insulation, were suggested, no study has quantitatively determined the contribution of either aspect. In this study, we developed a heat transfer model for a biochar-amended co-composting system based on the measurements from our two previously published studies conducted to co-compost poultry carcasses with woodchips and wood-based (WBC), distillers grain (DGBC), and cow manure (CMB) biochar. The two composting studies were conducted over three heating cycles, with two turnings separating each cycle. The simulation for the second heating cycle, during which the compost materials began to degrade and were well-mixed, showed an average R2 value of 0.86 and was selected for further analyses. Results from the model suggested that incorporating biochar into the composting mixture increases thermal conductive losses. For example, at a biochar addition rate of 13 % (v/v), the predicted longitudinal conductive resistance of the compost pile was reduced by 24.9 %. However, the total heat unit still increased by 11.2 ± 3.17 % due to the enhancement of microbial activity as supported by elevated oxygen consumption (38.1–61.1 %). When biochar was applied in layers on the surface of the composting bins, its impact on microbial activity was minimal, primarily functioning as an insulator. Under these conditions, the total heat unit was 8.7 % higher than the control. These findings suggest that biochar's primary effect on temperature development was through promoting microbial activity.

Structural Analyses of DP-1, a Protein with the Ability To Bind Gold Nanoparticles, by Using Nuclear Magnetic Resonance Spectroscopy.

Gold nanoparticles (AuNPs), consisting of metallic gold, are applied in various fields owing to their characteristic physical properties. Collimonas sp. D-25 (D-25) is a Gram-negative bacterium obtained from soil, compost, and other environmental materials in the Akita Prefecture. DP-1 is a water-soluble protein found in D-25 that binds specifically to AuNPs and retains them with high stability. This study aimed to identify the part of DP-1 that interacts with AuNPs and determine its 3D structure in solution using nuclear magnetic resonance spectroscopy. Peptide fragments obtained by trypsin digestion were examined for their AuNP-binding capacity to determine the key Au-binding domain of DP-1. A fragment consisting of 16 amino acid residues (GHAATPEQYGVVTANK) was identified as the peptide with the highest binding activity. Structural analyses of this peptide indicated that the main chain was elongated, and negatively charged residues in the side chain were exposed on the surface by incorporating AuNPs. These results suggest that DP-1 interacts with AuNPs through negatively charged residues and extended hydrophobic residues for protein-protein interactions. The structural data also provide new insights into biomimetic technologies.

Practical application of circularity micro-indicators to automotive plastic parts in an industrial context

The increasing amount of plastics in new vehicles, and the consequent growth of plastics in the automotive shredder residue, makes it imperative and urgent to improve reuse and/or recovery of plastics at the vehicle's end-of-life. Circularity micro-indicators can identify improvement guidelines and monitor the transition to a more circular economic model; however, the complexity, variety of scope and approach, and scarcity of information on most of the circularity micro-indicators hamper their practical adoption by companies.In this paper, we identify relevant micro-indicators for the automotive sector, focusing on key aspects for automotive plastic parts. Further, to showcase the application of these micro-indicators in a real industrial context, a case-study plastic automotive component was identified in collaboration with a tier II supplier and five complementary circularity micro-indicators were evaluated.We found 23 circularity micro-indicators (at the product level) that are highly relevant for automotive parts and we discuss individually how each can provide useful information. Results indicate an enormous improvement opportunity to improve circularity of plastic automotive parts, namely in the use of more sustainable material sources (recycled, bio-based, or compostable materials) and promotion of end-of-life recovery approaches (reuse or refurbish, and take-back systems).We concluded that practices adopted by industry to optimize production, in terms of design for manufacturing and design for assembly, as well as in the composition of plastic automotive parts, namely integral design, multi-material parts, or welding components made from different materials, severely limit the implementation of circular economy approaches, a situation that needs to be reverted by legislators and companies.

Development of modified compost unit for domestic biodegradable waste

As the human population grows, so does the amount of organic solid waste generated in cities. In India, waste generation has surged dramatically during the last decade, reaching 62 million tonnes per year. By 2030, garbage generation is expected to reach 165 million tonnes, necessitating the construction of a landfill the size of Bengaluru. Organic waste, on the other hand, can be diverted from landfills and composted, which is a more sustainable technique. The study was conducted to evaluate the performance of the rotary drum. The objective is to decrease informal refill, separate waste and increment the nature of fertilizer or excrement. This effort aims to turn solid waste to compost in as little as 4–8 weeks. The goal of this study was to see how well a composting barrel with a covering mechanism could reduce the release of foul odours during the composting of common household bio-waste. It is a promising idea to turn the substrates inside the barrel, however, the impact of turning frequency needs to be discussed more. For 30 days, physio-chemical parameters were assessed. Composts made from various organic wastes vary in quality and stability, which is also dependent on the composition of the raw material utilised in the composting process. The stability and maturity of compost are directly proportional to its quality. Finally, pH, temperature, and moisture content were analysed in the compost made with cow dung as a beginning pack. Physio-chemical changes were tracked for 4 to 8 weeks. Moisture content, temperature, odour and pH were all taken into consideration. It was found that temperature remained above 55 °C for a period of two days in the middle of composting duration. The pH drops to 7 in first 5 days, but eventually managed to stay neutral in the end. The moisture content reduced from 60 % to 54 % during the total composting period of 30 days.

Mitigation of ammonia emissions during food waste composting through acetic acid addition: A promising strategy for sustainable waste management

This research investigates using acetic acid to reduce ammonia emissions during composting while also evaluating its impact on microbial activity, compost quality, and nitrogen content. Composting is essential for recycling food waste and achieving renewable resource targets, but ammonia emissions pose environmental and health concerns. Addressing these issues is crucial for advancing composting technology and promoting sustainable waste management practices. The study reveals that adjusting the pH of compost piles to pH5, pH6, and pH7 reduced ammonia odor production by 65%, 40%, and 20%, respectively, compared to the control pile without acetic acid. The dominant bacteria, including Lactobacillus, Bacillus, and Aneurinibacillus species, played a crucial role in nitrification, leading to significant ammonia reduction during thermophilic and mesophilic phases. Additionally, nitrogen assimilation during composting enriches the nutrient content of the mature compost, as evidenced by seed germination indexes more significant than 80% in the treated piles. These findings contribute to optimizing composting processes and promoting sustainable agricultural circular economies.

Insight in molecular degradation patterns and co-metabolism during rose waste co-composting

Composting is recognized as a sustainable waste management strategy. However, little is known about green waste, and specifically rose waste, degradation patterns during composting. This study aimed (1) to gain insight in the underlying decomposition patterns during rose waste composting and (2) to identify co-metabolisms of ligneous material. Five different compost mixtures were tested ranging from pure rose waste to mixtures with tomato waste, kalanchoe waste or mature compost added. Samples were taken during a six-month experiment and analyzed by pyrolysis-GC/MS. The temporal trends in the relative abundance of 10 different compound groups were measured. Lignin and aliphatic compounds together accounted for ≥ 50% of the quantified pyrolysis products, but with changing contributions during composting. The relative abundance of polysaccharides and terpenes strongly decreased with more than 60% in the first 2 months. The simultaneous decrease in relative abundance of lignin and polysaccharides during initial composting phase indicated co-metabolism of lignin. The results from this study showed that while the presence of lignin is commonly regarded as a challenge in composting, it actually undergoes degradation through distinct mechanisms at the various composting stages.

Process Parameters and Conditions of Intensified Composting of Kitchen Biowaste

Abstract Composting is one of the efficient and effective methods of disposal and recovery of biodegradable waste. A favorable and intensified course of the composting process can be achieved by optimal composition of the composted material (moisture, content of organic substances and nutrients, C:N ratio, etc.), and also by optimizing the conditions under which composting takes place (temperature, pH, structure and aeration of the material, etc.). The paper contains a methodology for calculating the composition of composted material and also a methodology for solving the forced aeration process of composted material. More specifically, some process parameters of the intensified composting of a defined amount of kitchen biowaste, taking place in closed composting reactors, are presented and analyzed. Using the material balance of the composting process, the connections between the desired composition of the matured compost, the composition of the composted material and the conditions under which the composting takes place are pointed out. The specified connections enable the composting process to be optimized appropriately.

EFFECT OF PULP SLUDGE COMPOST VS. MANURE FERTILIZER APPLICATION TO THE GROWTH OF GERONGGANG (Cratoxylum arborescens) SEEDLINGS IN PEAT SOIL

The pulp industry is crucial for Indonesia, but the waste produced should be managed. Pulp sludge contains organic matter suitable for compost material. This study examines the response of geronggang (Cratoxylum arborescens) seedlings' growth to the application of pulp sludge compost compared to commercial manure fertilizer and non-fertilized soil for six months. A fifteen kg of pulp sludge (water content of 60-70%) mixed with decomposers (Penicillium citrinum and Penicillium oxalicum (107 spores/mL)) was incubated for a month. The compost or fertilizer at a dosage of 0, 2, 4, 6, 8, 10, 12, 14, and 16 (tons/ha) was added to peat soil for the seedlings' growing media. The manure fertilizer contained higher macronutrients than the sludge compost, while the peat was considered poor soil. Seedlings with sludge compost or manure fertilizer addition at a dosage equal to 2 (tons/ha) showed the highest survival rate after six months. The sludge compost addition raised the seedling's height, diameter, and dry weight more than another treatment. The sludge compost at a dosage equal to 16 and 12 (tons/ha) significantly increased the height and diameter of the seedlings, respectively. The sludge compost has shrink-swell characteristics that are potent water retention in dry soil.

Thermophilic compost inoculating promoted the maturity and mature compost inoculating reduced the gaseous emissions during co-composting of kitchen waste and pig manure

This study investigated the effects of inoculating thermophilic and mature composts on maturity, gaseous emissions, and bacterial communities during the co-composting of kitchen waste and pig manure. Results showed that the temperature peaked on day 4 of the inoculation compost amendment, which was earlier than the control treatment on day 8. In particular, the GI of the inoculated thermophilic compost was higher (88.65%) than that of other treatments (GI ≤ 61%) on day 35. The addition of the thermophilic compost promoted the enrichment of Bacillus and Planifilum, accelerated organic matter degradation, and enhanced maturity. Inoculation with mature compost reduced CH4 emissions by 50.66%, owing to the enrichment of methane-oxidizing bacteria (norank_f_Methylococcaceae). Furthermore, the mature compost decreased NH3 emissions by 36.16% through physical absorption and microbial activity (reducing NH4+ production). Inoculation with compost amendment increased N2O emissions owing to the enhanced denitrification of the nitrate reduction function. Overall, thermophilic compost addition enhanced the composting process and improved maturity, whereas mature compost addition was more effective in reducing gaseous emissions during the co-composting of kitchen waste and pig manure.