Rapid Composting Research Articles

Formulation of Novel Microbial Consortia for Rapid Composting of Biodegradable Municipal Solid Waste: An Approach in the Circular Economy

Urbanization and rapid industrialization have led to the escalation of municipal solid waste generation and accumulation. Composting is widely recognized as a sustainable solution for solid waste management. However, its long-term investment is considered a disadvantage. The present research study discusses the rapid biotransformation of solid waste into valorized compost. Bacteria were isolated from soil, solid waste, and leachate samples from open dump sites. From the 18 different bacterial consortia created using potential isolates, the five most promising consortia were selected based on concurrent different enzyme production. These selected consortia were incorporated into typical compost bins with Municipal Solid Waste (MSW). Daily monitoring of enzymatic activity, pH, conductivity, bulk density, moisture, and temperature, along with other composting parameters, was conducted. The study’s results demonstrated that consortium No. 5, comprising Bacillus haynesii, Bacillus amyloliquefaciens, and Bacillus safensis, exhibited significant (p<0.05) enzyme activity of cellulase, amylase, lipase and proteinase enzymes during composting compared to the control and other treatment setups. Consortium No. 5 also facilitated rapid and successful composting, as evidenced by significant alterations of composting parameters by exhibiting a shorter average composting time, reducing it from 110±10 days to 20±3 days, showcasing the potential applicability of formulated bacterial consortium as a sustainable and greener approach to the global solid waste problem. The novelty of this study lies in the isolation of local bacterial strains from open dump sites soil, MSW, and MSW leachate samples, which were then utilized in the composting organic fraction of MSW, enhancing the potential for effective waste management.

Isolation, screening and characterization of efficient cellulose-degrading fungal and bacterial strains and preparation of their consortium under in vitro studies.

In this investigation, cellulose-degrading fungi and bacteria were isolated from different partially decomposed cellulose-rich substrates, such as groundnut residues, rice straw, and rotten wood, following dilution plating techniques on carboxymethyl cellulose agar media and screening for potential cellulose degradation ability. The development of a clear halo zone surrounding the microbial colonies during the initial screening process using the Congo red test (20 isolates) suggested cellulose hydrolysis, and the highest cellulase production activity was implied by the isolates with the largest clear zone ratio (9 isolates). Using both macroscopic and microscopic examinations, as well as standard biochemical tests outlined in Bergey's Manual of Determinative Bacteriology, the genus-level identification of fungi and bacteria was accomplished. In order to molecularly identify the 4 isolatedfungal and bacterial strains at the species level after being ultimately selected for cellulase production potential under in vitro studies, fungal and bacterial DNA was extracted and amplified by PCR using the universal primers ITS1 and ITS4 for fungi (ITS rRNA, 5.8S rRNA) and 8F and 1492R for bacterial isolates (16S rRNA). After sequencing, the PCR results were compared to other comparable sequences in GenBank (NCBI). Based on the available NCBI data, phylogenetic analysis of their ribosomal gene partial sequences revealed that DAJ2 (PP086700) shares 100% homology with Aspergillus foetidus, DTJ4 (PP086699) shares 99.74% similarity with Trichoderma atrobrunnium, DBJ6 (PP082584) shares 100% identity with Priestia megaterium, and DMB9 (PP082585) shares 99.88% homology with Micrococcus yunnanensis. The cellulolytic potential of Phanerochaete chrysosporium is well established. Therefore, it was considered a standard culture for comparison and was collected from the MTCC, Chandigarh, India. Overall, all 4 selected isolates and the check organism were mutually compatible or synergistic with each other, and their consortium is useful for the accelerated decomposition of organic constituents during rapid composting.

Effect of fermentation materials reflux on gaseous emissions during perishable waste composting

Aiming at the problems of low bioconversion efficiency and serious secondary pollution of urban perishable waste (PW), fermentation materials reflux was applied in PW composting to investigate the effects of reflux modes on emission of ammonia (NH3), methane (CH4) and nitrous oxide (N2O) in this study. Before that, 20% was determined to be the optimal ratio of reflux in terms of the indicators of gaseous emissions and used in the current experiment. Five treatments including CK (no-reflux), T1 (reflux mature compost (MC), completely mixed with the initial material), T2 (reflux MC, 15% for initial mixing, 5% for surface covering), T3 (reflux MC, 10% for initial mixing, 10% for surface covering) and T4 (reflux thermophilic compost (TC) and MC, 15% TC for initial mixing, and 5% MC for surface covering). T2 reduced NH3 and CH4 emission by 52.9% and 40.11%, as a result of high temperature and inhibition of methanogens in the former stage. While T4 reduced the most N2O emission by 56.85% through the restraint of denitrification. In conclusion, the introduction of fermentation materials can accelerate the composting process, improve maturity, and mitigate greenhouse gas (GHG) emissions ranging from 27.61% to 58.05%, which can provide theoretical and technical support for rapid composting of urban PW in the future.

Rapid composting of groundnut residues through novel microbial consortium: Evaluating maturity, stability, and microbial activity

A laboratory pot experiment (Experiment 1) was conducted to determine the optimal ratio of groundnut haulm and shell as composting substrates. The aim was to identify the most effective combination for rapid decomposition under in vivo conditions. The experiment was carried out in 2022, from May to July, using a completely randomized design (CRD) with 6 treatments that were replicated 4 times. The treatment combinations in the pot experiment were as follows: T1: haulm + shell (1:1), T2: haulm + shell (2:1), T3: haulm + shell (3:1), T4: T1 + Cn, T5: T2 + Cn, and T6: T3 + Cn. Here, Cn refers to the cellulose-degrading efficient microbial consortium containing bacterial strains Priestia megaterium DBJ6, Micrococcus yunnanensis DMB9, and fungal strains Aspergillus foetidus DAJ2, Trichoderma atrobrunnium DTJ4, and Phanerochaete chrysosporium CBS129.27. Based on the results (results of chemical and biological properties) of the pot experiment, treatment T6 was considered the best treatment (the C/N ratio was 14.36 ± 0.444 after three months of decomposition) for further study under in vivo conditions. The in vivo experiment (Experiment 2) was conducted at the Jaguli Instructional Farm of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India, during the months of August to October in both 2022 and 2023 with two treatments: the normal composting treatment (NC) and the rapid composting treatment (RC). The findings of Experiment 2 showed that organic substrates degraded more quickly (within 90 days) during rapid composting, as evidenced by a decrease in the C/N ratio to below 15 (14.32 and 13.97 on day 90 in 2022 and 2023, respectively). Whereas, normal composting required more than 90 days to achieve a C/N ratio below 20 (23.80 and 23.15 on day 90 in 2022 and 2023, respectively). The RC treatment also showed a higher microbial population and enzyme activity compared to the NC treatment. Therefore, according to the results of this experiment, it can be concluded that the inoculation of the microbial consortium was more beneficial for accelerating the composting process under the same composting circumstances and substrate ratio.

Isolation and screening of potential lignocellulolytic microbes from Phra Nakhon Si Ayutthaya Province

Phra Nakhon Si Ayutthaya Province is an important area for rice cultivation in Thailand. However, large amounts of rice straw generated at harvest time are often burnt in the fields, causing environmental degradation and air pollution. To address this, rice straw composting by degrading microorganisms has been identified as an effective alternative for sustainable waste management, with potential applications in environmental biotechnology. For this study, 28 microorganism samples were collected from various sources in Phra Nakhon Si Ayutthaya Province, including a corrugated paper manufacturer, plant-cultivated soil, compost from dung, black soldier flies, and vermicompost. Lignocellulolytic microorganisms were screened for cellulase, xylanase, and manganese peroxidase production on agar plates and broth media using commercial and rice straw substrates. The lignocellulolytic activities were compared among the isolated and non-pathogenic microorganisms. A microbial consortium with high potential to degrade rice straw was identified, consisting of two thermophilic bacteria, Bacillus licheniformis BKT1 and BOT4, two mesophilic actinomycetes, Streptomyces ardesiacus AQ4 and An6, two thermophilic actinomycetes, Streptomyces thermoalcalitolerans APT3 and Streptomyces thermoviolaceus subsp. thermoviolaceus AQT2, and two fungi, Penicillium sp. Fh11 and Aspergillus sp. Fj6. This microbial consortium induced rapid composting of rice straw, thereby supporting sustainable agricultural waste management and reducing PM25 air pollution.

Exploitation of Cellulase Producing Bacterial Strains from Mangrove Soils for Rapid Composting of Leaf Litter

Exploitation of Cellulase Producing Bacterial Strains from Mangrove Soils for Rapid Composting of Leaf Litter

Characterization of Cellulose-Degrading Bacteria Isolated from Silkworm Excrement and Optimization of Its Cellulase Production.

An abundance of refractory cellulose is the key limiting factor restricting the resource utilization efficiency of silkworm (Bombyx mori) excrement via composting. Screening for cellulose-degrading bacteria is likely to provide high-quality strains for the safe and rapid decomposition of silkworm excrement. In this study, bacteria capable of degrading cellulose with a high efficiency were isolated from silkworm excrement and the conditions for cellulase production were optimized. The strains were preliminarily screened via sodium carboxymethyl cellulose culture and staining with Congo red, rescreened via a filter paper enzyme activity test, and identified via morphological observation, physiological and biochemical tests, and phylogenetic analysis of the 16S rDNA sequence. Enzyme activity assay was performed using the 3,5-dinitrosalicylic acid method. DC-11, a highly cellulolytic strain, was identified as Bacillus subtilis. The optimum temperature and pH of this strain were 55 °C and 6, respectively, and the filter paper enzyme activity (FPase), endoglucanase activity (CMCase), and exoglucanase activity (CXase) reached 15.40 U/mL, 11.91 U/mL, and 20.61 U/mL. In addition, the cellulose degradation rate of the treatment group treated with DC-11 was 39.57% in the bioaugmentation test, which was significantly higher than that of the control group without DC-11 (10.01%). Strain DC-11 was shown to be an acid-resistant and heat-resistant cellulose-degrading strain, with high cellulase activity. This strain can exert a bioaugmentation effect on cellulose degradation and has the potential for use in preparing microbial inocula that can be applied for the safe and rapid composting of silkworm excrement.

Isolation and Screening of Lignocellulolytic Microbes from Cow Dung for Rapid Composting of Rice Straw

The present work aimed to isolate and screen the lignocellulolytic microbes from cow dung, partially decomposed straw, forest soil. A total of 60 isolates from which 41 bacterial, 15 fungal and 4 actinomycetes distinct isolates were obtained were further subjected to lignocellulolytic screening. The 60 isolates when screened for their ability to produce cellulase enzyme 21 bacterial isolates showed positive. Highest halo zone was shown with greater hydrolysis capacity ranging from 1.04 to 2.58. The 60 isolates were then subjected to screening for lignolytic activity by using methylene blue, azure B as indicator for bacteria and tannic acid as indicator for fungi. Out of them 11 bacterial isolates showed decolourisation of methylene blue and azure B and 4 fungal isolates were found to exhibit positive for tannic acid assay which is indication for lignolytic activity. Among these 60 isolates 3 bacterial isolates CD-5, PDS-3, and PDS-6 showed both cellulolytic and lignolytic activity.

Effect of moisture content, aeration rate, and C/N on maturity and gaseous emissions during kitchen waste rapid composting

To determine factors affecting compost maturity and gaseous emissions during the rapid composting of kitchen waste, an orthogonal test was conducted with three factors: moisture content (MC) (55%, 60%, 65%), aeration rate (AR) (0.3,0.6 and 0.9 L·kg−1DM·min−1) and C/N ratio (21, 24, 27). The results showed that the importance of factors affecting compost maturity was: C/N > AR > MC, optimal conditions were: C/N of 24, AR of 0.3 L·kg−1DM·min−1and MC of 65%. For gaseous emissions, the sequence of essential factors affecting NH3 emissions was: C/N > MC > AR, and the optimal parameters for NH3 reduction were: C/N of 27, MC of 65%, and AR of L·kg−1DM·min−1. The important factors affecting N2O and H2S emissions are both: MC > C/N > AR, while their best parameters were different. The optimal parameters for N2O emission reduction were MC of 60%, AR of 0.3 L·kg−1DM·min−1 and C/N of 24, while these for H2S were MC of 55%, AR of 0.3 L·kg−1DM·min−1 and C/N of 21. The C/N mainly affected the compost maturity and AR further affected the maturity and pollutant gas emissions by influencing the temperature and O2 content. Considering comprehensively the maturity and gaseous reduction, the optimal control parameters were: MC of 60%–65%, AR of L·kg−1DM·min−1, and C/N of 24–27.

Development and Fabrication of A Portable Shredding Machine for Rapid Composting of Organic Waste

Solid waste management is found to be a matter of great concern all over the world. As the population grows, the volume of food waste also increases. Vegetable waste discarded from markets, waste discarded from slaughterhouses, and food waste left out after large social gatherings are becoming unmanageable heaps of organic waste. Composting is an effective process that can be used for the biodegradation of solid waste. Researchers have studied the influence of many parameters to accelerate the composting process such as adjusting the C/N ratio, pH, temperature, and moisture content. Reducing the size of larger pieces into small particles is found to accelerate the microbial activity and hence composting. This paper discusses the development and fabrication of a shredding machine used for cutting large volumes of vegetable waste. As per the studies conducted, the shredding machine can cut down 360 kg of vegetable waste into shredded waste within one hour. The quantity of petrol required for operating the engine for one hour was observed as one liter. Hence the fabricated shredding machine is found as cost-effective. The portable unit can be taken to various locations where solid organic waste has to be shredded and hence there is no need to transport waste which is a cumbersome task that consumes more energy.

Enhanced Composting Efficiency and Removal of Heavy Metals and Antibiotics Via Rapid Composting

Enhanced Composting Efficiency and Removal of Heavy Metals and Antibiotics Via Rapid Composting

Effects of Moisture Content, Aeration Rate, and C/N on Maturity and Gaseous Emissions During Kitchen Waste Rapid Composting

Effects of Moisture Content, Aeration Rate, and C/N on Maturity and Gaseous Emissions During Kitchen Waste Rapid Composting

Food waste composting based on patented compost bins: Carbon dioxide and nitrous oxide emissions and the denitrifying community analysis

Mature compost and rice bran were used as bulking agents to perform Food Waste Rapid Composting (FWRC) in a patented composting bin. The characteristics of CO2 and N2O emission and the denitrifying community were investigated. The release of CO2 and N2O concentrated in the early composting stage and reduced greatly after 28 h, and the N2O emission peak of the treatment with mature compost was 8.5 times higher than that of rice bran. The high N2O generation resulted from massive denitrifying bacteria and NOx--N in the composting material. The relative abundances of denitrifiers, correspondingly genes of narG and nirK were much higher in the treatment with mature compost, which contributed to the N2O emission. Moreover, the correlation matrices revealed that N2O fluxes correlated well with moisture, pH, temperature, and the abundances of nirK and nosZ genes during FWRC.

Rapid composting of food waste and yard waste with effective microorganisms (EM)

Rapid composting is an alternative method to reduce highly generated food waste and yard waste discarded to the landfill. This study aims to determine the effect of effective microorganisms (EM) application on the chemical and physical properties and to determine the performance and factors affecting the rapid composting process. The chemical and physical properties such as pH, temperature, moisture content, carbon-to-nitrogen (C/N) ratio and Nitrogen (N), phosphorus (P) and Potassium (K) nutrient are examined over rapid composting period in order to assess the performance of compost and effectiveness of EM in enhancing the degradation process of organic waste. There are three compost prepared which are A, B and C that received different ratio of EM which 1 L, 2 L and 3 L respectively. Based on the result obtained from the 54 days of composting conducted, compost A, B and C show no significance differences on parameters tested. The temperature obtained mostly within the range 35-38 °C, pH values are 5-9, moisture content are 20-60 % and for NPK nutrient, Total Nitrogen content are 1.3 % to 1.4 %, Total Phosphorus are within 0.10 ppm to 0.45 ppm and Potassium are within 0.8 ppm to 6.7 ppm.

Fate of antibiotic resistance genes in industrial-scale rapid composting of pharmaceutical fermentation residue: The role implications of microbial community structure and mobile genetic elements

Composting is an effective technology to recycle organic solid waste as a green resource. However, pharmaceutical fermentation residue (PFR) contains a variety of pollutants, such as residual drug and antibiotic resistance genes (ARGs), which limits the green cycle of using PFR as a resource. To promote the green recycling of PFR, this study evaluated the characteristics of abundance and the response relationship of ARGs during the process of rapid composting. Different rapid composting samples were collected, and DNA was extracted from each sample. The absolute abundance of ARGs was quantified using quantitative PCR, and the microbial community structure was identified using high-throughput sequencing. The results showed that ermB, ermF, tetM and tetQ were reduced by 89.55%, 15.10%, 89.55%, and 82.30% respectively, and only sul2 increased by approximately 5-fold. Mobile genetic elements (MGEs) directly affected the changes in abundance of ARGs. As typical MGEs, intl1 and intl2 decreased by 3.40% and 54.32%, respectively. Potential host microorganisms important factors that affected ARGs and MGEs. A network analysis indicated that the potential host microorganisms were primarily distributed in Firmicutes and Proteobacteria at the phylum level. The pH and content of water-extractable sulfur were physicochemical parameters that substantially affected the abundance of potential host microorganisms through redundancy analysis. Industrial-scale rapid composting could reduce the number of ARGs and shorten the composting cycle, which merits its popularization and application.

Effect of Alkaline Pre-Treatment of Some Straws as a Rapid Composting Process on Soil Properties and Crop Productivity

Effect of Alkaline Pre-Treatment of Some Straws as a Rapid Composting Process on Soil Properties and Crop Productivity

Dynamics of maturity and stability indices during decomposition of biodegradable city waste using rapo-compost technology

Expeditious growth of population and urbanization has led the global challenge for Municipal Solid Waste (MSW) management. An investigation on rapid composting of biodegradable city waste was carried out with three treatments, two on a rapo-composter with and without consortia of thermophilic ligno-cellulolytic microbes and third is the common practice of compost producer. The quality of compost i.e. the maturity and stability index was tested at four different stages of decomposition. After 30 days of decomposition it was elucidated that rapo-composter with consortia (Bacillus sps., Streptomyces sps., Rhizomucor pusillus and Aspergillus flavus) fasten the decomposition time. This paper finds uniqueness in deriving 10 maturity parameters, 6 stability parameters with one parameter as confirmatory test of compost toxicity. It was concluded from the study that the Water Soluble Carbon (WSC) and Organic Nitrogen (Org. N) ratio is the key regulator of maturity parameter and the dehydrogenase (DHA) activity is important factor for compost stability.

Production of cost affordable organic manure using institutional waste by rapid composting method

This project is an initiative to convert the solid waste (easily available inside Bannari Amman Institute of Technology campus, Sathyamangalam, Erode District.) to compost within a short duration of 14 to 18 days by rapid composting. The wastes included in the composting comprises materials such as vegetable cuttings, dry and wet leaf twigs, grass clippings, tree trimmings etc. That’s where composting steps in; organic waste can be recycled through composting and the resulting product can be used to improve soil quality and help plants grow. The size of the composting bin was 3 feet × 3 feet × 3 feet. Alternate layers of wet waste and dry waste were added to the composting bin. Saw dust and cow dung were used as the accelerators. Quantity of waste added was: Wet waste − 169 kg, Dry waste – 66 kg, saw dust − 24 kg which was in the ratio 7:2.75:1. Wastes were chopped to 0.5 to 1.5 in. for better composting. The dry leaves are used only for burning (which causes air pollution and causes health hazards), as an alternative we made compost with dry leaves combining with wet waste. This can be readily adopted in colonies, schools and colleges where dry and wet wastes are easily available. The resultant product of compost obtained is used as manure for plants inside the institution campus.

Collegial effect of maggots larvae and garbage enzyme in rapid composting of food waste with wheat straw or biomass waste

The high moisture content, low carbon/nitrogen ratio and higher oil & fat contents in the post-consumer food waste make it unfavourable for its application to the composting process. The present study is an attempt to develop favourable conditions for rapid composting of post-consumer food wastes through a novel combination of garbage enzyme and maggots’ larvae (0.04 g of maggots per gram of waste) in different combination of food waste with wheat straw and biomass waste, respectively. The in-vessel composting experiments were conducted in three polystyrene vessels out of which the Vessel 1 contained only food waste, Vessels 2 and 3 contained food waste with wheat straw and biomass wastes in the ratio 3:2, respectively. Indigenously prepared garbage enzyme and the isolated maggots’ larvae were introduced in the same amount in all the vessels to observe its effect on the composting process. The co-composting of these combinations was carried out and its comparative analysis was also performed. The maximum organic matter degradation of 77.72 ± 0.11% was found in Vessel 2 with a ‘k’ value of 0.15 d−1, while, the organic matter degradation of 76.98 ± 0.01% and 76.21 ± 0.07% with a ‘k’ value of 0.12 d−1 and 0.1 d−1 was observed in Vessels 1 and 3, respectively. A significant reduction in heavy metals along with high bioaccumulation factors was detected in maggots’ larvae. It is comprehended that applying the requisite combination of maggots’ larvae and garbage enzyme can prove to be a feasible solution for rapid and efficient composting of post-consumer food wastes with a different combination of agricultural and biomass wastes.

Combined Addition of Bovine Bone and Cow Manure: Rapid Composting of Chestnut Burrs and Production of a High-quality Chestnut Seedling Substrate

In China, chestnut burrs (CB) are produced at a rate of a million tons per year as the major byproduct of chestnut orchards. It is necessary to utilize the chestnut forest green waste and convert it into a valuable seedling media for the sustainable cultivation of chestnut seedlings. In this study, we composted CB with two waste products of cattle farming, namely cow manure (CM) and bovine bone (BM). We also evaluated the potential of CB compost application in chestnut forest sustainability. Results indicated that the best combination was the addition of 15% BM and 55% CM. This combination significantly improved the composting environment by increasing pH, enhancing phosphorus concentration and mineral elements such as Ca, Na, Mg and Zn, and shortened the composting period to 38 days. This combination also resulted in the highest content of citric acid-P (109.20 times than the control treatment) and the lowest content of NH4+–N (0.28 times than control treatment) indicating a better N and P structure of the final compost product. This combination achieved a greater degradation rate of CB cellulose (61.45%), hemicellulose (37.87%), and a more significant degradation of outer epidermis structure. When CB compost was used as a growing media, a significant decrease in photosynthesis stress of chestnut seedlings was observed, which was mainly manifested as a decrease in photochemical quenching (qP) and an increase of the maximum efficiency of PSII photochemistry under dark-adaption (Fv/Fm). Addition of 10% CB compost (in volume basis) is suggested, which resulted in the tallest chestnut seedlings (59.83 cm) with a stem diameter of 0.91 cm after six months of growth. In summary, this research provides an environmentally friendly strategy for chestnut orchard sustainability: rapid composting of CB, then immediate application as a high-quality substrate for chestnut seedlings.