Rotary Drum Composter Research Articles

Performance Analysis of a Solar-Powered Rotary Drum Composter for Optimized Food Waste Management

The annual value of food waste generated worldwide has already reached a staggering $1 trillion. This amounts to 1.3-1.4 billion tons, or one-third of the food produced for human consumption, that goes to waste each year. The Food Center at Don Honorio Ventura State University faces a similar issue, with a weekly production of 21.5 kg of food waste. To address this increasingly concerning issue, a solar-powered rotary drum composter driven by a DC motor was developed. This composter is designed to accommodate up to 20 kg of food waste. Analysis of the composter’s motor performance reveals significant relationships between voltage, current, speed, torque, efficiency, and load. The voltage exhibits an inversely proportional relationship with the load, steadily decreasing from 24.8 V to 23.3 V as the load increases, while the current shows a directly proportional relationship, consistently rising from 4.1 A to 9.84 A with the increased load. Further examination of torque and speed in relation to load indicates a directly proportional and inversely proportional relationship, respectively. Torque increases from 6.68 Nm to 27.23 Nm with increasing load, while speed decreases from 72.74 rpm to 55.16 rpm. As for efficiency, it was found that the composter operates most efficiently when the drum is loaded with 12 kg, beyond which efficiency gradually declines with increasing load up to 20 kg. This decline signifies the diminishing returns associated with higher loads, highlighting the importance of load optimization for sustained efficiency in composter operation.

Rotary Drum Composting of Organic School Wastes and Compost Valorization

Inappropriate waste disposal imposes significant health risks in densely populated urban environments and schools, necessitating sustainable waste management. Therefore, a study was carried out at Al-Jazaer School, Kuwait, to evaluate rotary drum composting (RDC) of organic school waste comprising used paper, dry leaves, and vegetable food wastes in a 1:4:20 ratio. Feedstock comprising 42% organic school wastes, 42% horse manure, and 16% sawdust produced mature compost with a C:N ratio of 20.55 on the 43rd day of composting. Distinct mesophilic, thermophilic, cooling, and curing phases were observed during composting. Mature compost recorded a moisture content of 54.3%, pH 8.56, EC of 2.71 mS/cm, total nitrogen of 0.77%, total organic carbon of 18.25%, carbon content of 15.86%, and sulfur content of 0.14%. Soilless growing media comprising peat moss, perlite, and rotary drum compost in three proportions (1:1:1, 1:1:2, and 1:1:3), and peat moss, perlite, and commercial organic compost in a 1:1:3 ratio were evaluated for greenhouse vegetable production. The performance of cucumbers (Cucumis sativus cv. Ramos) raised in the lowest proportion of in-house prepared rotary drum compost (1:1:1 ratio) was comparable with that raised in the highest proportion of commercial compost (1:1:3). The study revealed the potential of RDC for decentralized sustainable waste management at the small-community scale and the suitability of compost from school wastes for soilless culture.

Bioconversion of Lantana camara into an agricultural bioproduct through rotary drum composter

Bioconversion of Lantana camara into an agricultural bioproduct through rotary drum composter

Evaluating the potential of biodegradation of swine manure through rotary drum composting utilizing different bulking agents

The rapid expansion of the pig industry and the concurrent increase in pig units have posed a significant waste management challenge, particularly in the form of piggery waste. In this study, the potential of three different bulking agents (sawdust, dry leaves, and rice straw) for the biodegradation of piggery waste was evaluated through rotary drum composting (RDC). Following the composting time of 20 days, evaluations of macro and micronutrient concentrations and the C/N ratio revealed stable, matured compost that could be used in farming. However, the saw dust amended RDC (RDC1) outperformed among the studied trails; the total nitrogen content of 1.54%, total phosphorus of 7.68 g kg-1, and total potassium of 23.45 g kg-1 demonstrated the bioproduct produced through RDC1 resulted in superior-quality end product achieved in only 20 days in comparison with other bulking agents studied. Further, the outcomes of the study can serve the swine livestock sector through effective bioconversion of the waste.

Bioconversion of Eichhornia crassipes into vermicompost on a large scale through improving operational aspects of in-vessel biodegradation process: Microbial dynamics

Eichhornia crassipes is a common, abundant aquatic weed biomass found globally. The present study examined optimum biodegradation procedures through batch studies (550 L rotating drum composter) and the resulting best combination on a large scale (5000 L rotary drum composter). The pilot scale rotary drum reactor was commenced with cow manure and then treated for 3 months with 250 kg/day of homogenously mixed E. crassipes and dry leaves. The rotary drum's inlet and outlet temperatures were 60 °C and 39 °C, respectively, suggesting thermophilic conditions with a 7-day waste retention duration. Eisenia fetida was used for vermicomposting the outlet material for 20 days, raising the nitrogen content to 3.2%. Bacterial diversity (16S-rRNA) sequencing revealed that Proteobacteria and Euryarchaeota are the most predominant. After 27 days, the volume dropped by 71%, and the product was stable and soil-safe. Large-scale optimised biodegradation may be a better way to handle aquatic weed biomass.

Thermophilic-mesophilic biodegradation: An optimized dual-stage biodegradation technique for expeditious stabilization of sewage sludge

The present study investigated the stabilization of fresh sewage sludge through a dual-stage biodegradation process; rotary drum composting in series with vermicomposting. After thermophilic exposure in a rotary drum composter, the partially degraded feedstock was separated into S1 without vermiculture, S2 and S3 with Eudrilus eugeniae and Eisenia fetida vermi-monocultures, respectively. The S3-derived vermicompost exhibited an 80% and 88% reduction in CO2 and ammonium-nitrogen evolution rates, respectively, demonstrating the expedient stabilization of sludge. The robust, more than 85% seed germination index supported S2 and S3 derived vermicompost viability. A significant decrease in heavy metals was evinced with S2 and S3-derived vermicompost; the S1-derived end product exhibited higher Zn, Cr, and Pb levels in the absence of vermicomposting. Furthermore, soil amended with 20% vermicompost from S3 displayed 50% more plant growth than S1. Thus, the optimized thermophilic-mesophilic dual-biodegradation technique stabilizes sewage sludge quickly, has a lot of potential in sludge management facilities around the world, and produces a marketable end product.

Performance assessment of in-vessel composter through heavy metal immobilization and humification of Parthenium hysterophorus

The bioconversion of Parthenium hysterophorus was performed through rotary drum composter and examined the mechanism of humification and heavy metals immobilization in the process. The 20th day compost contains a significant increase in humic substances of 28.7% compared to the initial day mix. The bioavailable fractions of heavy metals have reduced by 30 to 55% in the 20th day compost compared to the initial day mix. The leaching potential of cadmium has been reduced by 69% in the 20th day compost. The immobile fractions (F5) of Cd, Ni and Pb have been increased to 100, 99 and 78% in the 20th day compost. The mitotic index was increased by 1.7 and 51.6% in 25% dosed compost extract compared to the control and P. hysterophorus extract respectively. The transition of heavy metals to immobile fraction indicated the biodegradation capability of P. hysterophorus through rotary drum composting.

Biodegradation of an intrusive weed Parthenium hysterophorus through in-vessel composting technique: toxicity assessment and spectroscopic study.

Parthenium hysterophorus is a toxic terrestrial weed with its erratic behavior brought on by the presence of toxic compounds. A numerous works have been conducted on the complete eradication of this weed, but due to the residuals exists in soil, the weed re-grows. Current study therefore aims at examining the transformation of this weed by an in-vessel composting approach (rotary drum composter) and the evaluation of toxicity characteristics using Vigna radiata and Allium cepa as bioindicators. The nutritional content such as total Kjeldahl nitrogen (TKN), total phosphorus (TP), and total potassium were increased by 38.8, 39.1, and 49.5%, respectively, and the reactor was effective in reducing the biochemical content such as lignin, hemicellulose, and cellulose by 43.5, 50.7, and 57.3%, respectively, in the final compost. The thermophilic degradation phase in the reactor existed up to the 8th day of the composting process, which exhibits the highest degradation phase. Meanwhile, the degradation of phenolic, aliphatic, and lignocellulose was investigated and validated using Fourier transform infrared spectroscopy (FTIR) and powdered X-ray diffraction (PXRD) analysis. Although P. hysterophorus exhibited phytotoxic and cyto-genotoxic effects in plant models at the beginning of the composting process, the toxicity potential appeared to be reduced after 20days of composting. Therefore, the study's findings proved that the in-vessel composting of P. hysterophorus can produce a nontoxic, nutrient-rich compost product that could be used as a soil conditioner in agricultural farmlands. The insights of the study are not limited to the nutritional, stability, and quality characteristics but also the toxicity characteristics during the composting process.

Performance evaluation of a novel two-stage biodegradation technique through management of toxic lignocellulosic terrestrial weeds

The present study investigates the biodegradation of two potentially toxic terrestrial weeds Parthenium hysterophorus and Lantana camara, implementing a novel two-stage biodegradation technique; Rotary drum composting followed by vermicomposting (RV). The RV approach was refined for a 7-day thermophilic degradation in an in-vessel rotary drum composter, followed by a 20-day mesophilic degradation utilizing Eisenia fetida and Eudrilus eugeniae vermi-monocultures. However, rotary drum composting (RDC) was performed for both the weeds (for 27 days), facilitating only initial thermophilic degradation to compare the efficacy of the RV technique. Lignocelluloses analysis revealed that cellulose degradation doubled during RV technique, indicating efficient biodegradation in reactors administered with E. fetida vermiculture compared to RDC (19.60 to 42.80% and 26.80 to 66.50% in P. hysterophorus and L. camara feedstocks). Further, these results also correlated with the X-Ray diffractograms of all trials showing the degradation of crystalline cellulose at 2θ: 20–50° for RV. Moreover, to ensure product safety, the analyzed total heavy metals content also unveiled the advantage of RV over RDC as validated by the accumulation of higher concentrations of zinc (45% and 33% in P. hysterophorus and L. camara feedstocks) and lead (55% and 45% in P. hysterophorus and L. camara feedstocks) in reactors with E. fetida. The material’s seed germination index increased to 80% in the final product of all trials in the RV technique, indicating the diminishing of the phytotoxic nature. Subsequently, pot studies also indicated that the RV technique was coherent in managing noxious weeds.

Organic waste management by two-stage composting process to decrease the time required for vermicomposting

A fully matured product from a traditional vermicomposting method takes 45–60 days, which is 25–30 days longer than a rotary drum composting technique. Therefore, the use of rotary drum compost would minimize the vermicomposting period by 15–20 days. Very limited studies were available on combined technologies used for the biodegradation of invasive weeds. In this research, in-vessel composting and vermicomposting technologies are proven to be best in time reduction and produce mature, stable, and nutrient-rich compost that is more superior quality than conventional rotary drum compost. Esenia fetida, Eudrilus eugeniae, and Perionyx Ceylanesis were used to choose the best earthworm species for surviving with a low death rate and producing high-quality compost. For vermicomposting of pre-degraded waste, four separate reactors were set up: one with E. fetida (VrEF), one with E. euginae (VrEE), one with P. ceylanesis (VrPC), and one sans earthworm species (VrC). Vermicompost made from waste by all earthworm species exhibited a better nutritious value than control. Furthermore, E. fetida produced vermicompost with total Kjeldahl nitrogen (TKN) content of 3.24%, 12.87 g/kg total phosphorus (TP), and 22.08 g/kg potassium. The breakdown of complicated chemicals into simpler forms is confirmed by FTIR spectra. To confirm the vermicompost product, a germination assay was conducted on Vigna radiata. As a result, vermicomposting is the most effective nutrient recovery method. Weed management and the usage of two-stage compost products in the agro-industry could benefit from the current research.

Biowaste composting process - comparison of a rotary drum composter and open container

Composting is recognized as a sustainable waste management approach in which microorganisms treat and stabilize biodegradable waste under aerobic conditions to obtain compost as a final product. In this paper, composting of biowaste in a rotary drum composter (closed system) and an open container (open system) was compared. Temperature, pH, electrical conductivity, a carbon-to-nitrogen mass ratio (C/N ratio) and contents of moisture, carbon and dry and volatile matter, were measured during composting. Results showed decreasing profiles for moisture, volatile matter, and carbon contents, as well as for the C/N ratio, while increasing profiles for the dry matter content and electrical conductivity during composting in both systems. Leachates were formed only during the first three days of composting and were characterized with high organic loads, high ammonia concentrations, low pH, and high conductivity and turbidity. The organic matter content data during the composting process were analysed according to the first order kinetic model. Results suggested that there was a difference in the rate of organic matter decomposition, which was higher when composting in the open vessel than in the rotary drum composter.

Process optimization by combining in-vessel composting and vermicomposting of vegetable waste

The process parameters of in-vessel rotary drum composting (RDC) with vermicomposting (VC) were investigated for the conversion of vegetable waste into vermicompost. After 7-day initial thermophilic exposure (maximal 51.5 °C in 24 h), the partially degraded RDC waste was divided into R1 (no vermiculture), R2, R3, and R4 (with Eudrilus eugeniae; Eisenia fetida; and Perionyx excavates monocultures, respectively). R3 derived vermicompost displayed maximum optimal process parameters and desirable compost qualities. Against the constant 2.2% nitrogen content of R1, an increase from 1.4 to 4.15% was seen in R3, with a 52.5% reduction in total organic carbon (TOC). A clear testimony to the enhanced nutritional content and fitness of the novel combination of RDC thermophilic biodegradation and E. fetida based vermicomposting. In an environmentally compatible mode, the faster organic deconstruction in 27 days could substantially alter organic waste treatment in the immediate future.

Assessing mobility and chemical speciation of heavy metals during rotary drum composting of Ageratum conyzoides

Ageratum conyzoides, a goat weed that has invaded the world with its disparate behaviour through the inherence of heavy metal against the cultivated crops. The present study enrapt on composting of this disparate weed by assessing the heavy metal virulent throughout the composting process. A 550 L rotary drum composter (an In-vessel composting technique) was used for managing Ageratum conyzoides biologically by blending with inoculum and sawdust. It was evident that the substrate’s volatile solids and biological parameters were high and decreased in the final compost product. The first-order decay model was used for biological parameters and volatile solids through adjusted R2 ksBOD (R2=0.975), ksCOD (R2=0.974 and kV S (R2=0.941) respectively. The mass balance concept was utilised to evaluate the dynamics of the rotary drum composting process. The heavy metal virulent was assessed through bioavailable forms, and leachable heavy metals with chemical speciation fractions were carried out in the composting process. Ni and Cd were found predominantly in residual fractions with 99.7% and 99.5% in final day compost. Pb, Cr, Mn, Fe, Cu and Zn were moderately leached in mobile fractions throughout the composting process. The study stipulates the dynamics of heavy metals in the rotary drum composting process and indicates the compositions of every metal in various distinguished chemical fractions.

Effect of Microbial Inoculum and Leachate Circulation on the Performance of Rotary Drum Composter Used for Household Wet Biodegradable Waste

To reduce transportation costs and harmful environmental impacts, the household wet biodegradable waste (HWBW) should be segregated and processed at the source of generation. In the present study, the performance of a decentralized rotary drum composter (capacity = 160 L) was evaluated for the stabilization of HWBW. The system was divided into four compartments and approximately 2.5 kg of HWBW was added in each compartment for 10 days. Two sets of experimental runs were conducted to examine the effect of inoculum addition along with the leachate circulation on the biodegradation process and compost quality. The composting process was assumed to be over in ~ 40 days after the temperature reduced to the ambient level. The inoculum addition slightly improved the degradation rate while reducing the composting period though no considerable effect could be observed by leachate circulation. The compost yield (< 4 mm fraction) during both sets of studies was 15–18% and its quality satisfied the prescribed Indian standards. To ensure production of the good quality compost, germination and self-heating tests were also performed. The results revealed that mixing of compost (20%) with soil enhanced the growth of cress plants. Apart from this, the waste decomposition rate was also predicted using various kinetic models available in the literature.

On-farm screw press and rotary drum treatment of dairy manure-associated antibiotic residues and resistance.

An on-farm solid-liquid separator (SLS) and rotary drum composter (RD) manure treatment system was monitored for its impact on antibiotic residues and antibiotic resistance genes (ARGs). Administered antibiotics were tracked, and treatment system mass flows were quantified. Total amounts of antibiotic residues and ARGs were calculated from measured concentrations and mass flows. Only oxytetracycline (OTC) and sulfadimethoxine (SDM) were detected in the manure treatment system influent. No β-lactams were measured despite comprising ∼25% of the antibiotics administered. Nearly 80% of OTC and>90% of SDM partitioned into SLS liquid effluent (SL). The RD reduced the mass of OTC remaining in the SLS solid effluent (SS) significantly by 50%, whereas the mass of SDM appeared to increase after RD treatment. All four ARGs tested were detected in influent, with>70% of the sul1, blaOXA-1 , and intI1 genes (normalized by the 16S ribosomal RNA gene) partitioning into the SL. In contrast, about eight times more normalized tetO gene copies partitioned into the SS than in the SL. All ARGs remaining in the SS were significantly reduced by the RD treatment, with a noteworthy 98% reduction in normalized tetO gene copies. This study provides insight into on-farm levels of antibiotic residues and ARGs in dairy manure, their partitioning during SLS treatment, and their fate after a high-temperature RD treatment reaching 72.2 ± 0.18 °C near the outlet. It also notes the importance of mass-flow standardization of data, and the need to work towards standardization of manure system sampling protocols for antibiotic residues and ARGs.

Effects of Recirculation of Exhaust Air in Rotary Drum Composter on Composting Properties and Energy Consumption

Rotary drum composting appears to be a good option for decentralized composting. While aiming to transform the feedstock organic matter into stable humic compounds, composting should also take into account energy conservation. This experimental study quantified the impacts of exhaust air of a 0.38 m3 fully-automatic rotary drum composter on output parameters, decomposition rates, and energy consumption per loss of organic matter. Decomposition rates of labile and recalcitrant parts were evaluated using a multi-component kinetic model. The recirculation processes of exhaust air in the rotary drum composting enhanced the decomposition rates and maintained a better heat retention. In particular, the rotary drum composter with the dynamic gas recirculation system led to more matured material according to final C/N and $${\mathrm{NH}}_{4}^{+}-\mathrm{N}/{\mathrm{NO}}_{3}^{-}-\mathrm{N}$$ ratios, and germination index as well as to less energy consumption per loss of organic matter in reaching the stabile humus compounds in the final material as fast as possible.

Evaluation of rotary drum composting for the management of invasive weed Mikania micrantha Kunth and its toxicity assessment

Mikania micrantha Kunth is an abhorrent weed that destroys agricultural output. It contains toxic compounds that are detrimental to the natural ecosystem and have negative impacts on the economic and aesthetic aspects of the environment. This study depicts the treatment and management of this plant by in-vessel composting using a 550 L rotary drum composter. Six different mix proportions of biomass, cow dung, and sawdust were used for the study. Rotary drum (RD2) with 2.71% has the highest Total Kjeldahl Nitrogen (TKN). Total Organic Carbon (TOC) decreased to 19.72% at the end of the 20th day. Final C/N ratio falls between 7 and 14 in all the reactors. The phytotoxicity test of Mikania was evaluated using Vigna radiata and Allium cepa. The findings of the study suggest that Mikania can be efficiently utilised to produce mature and stable compost that might be recommended for field application as the process can reduce toxicity.

Kinetics and physics during composting of various organic wastes: Statistical approach to interpret compost application feasibility

Surge in the demand for compost applicability in enhancing the overall soil health has prioritized the need to evaluate and interpret the engineering aspect of composting and quality product. Although studies on various facets of biological and chemical properties are plenty, its interplay with waste degradation rate, and physical properties were barely investigated in terms of compost applicability. Rate of degradation varies for different wastes that dramatically affects the transformation of organics. Present research on composting of optimized mix proportions from earlier literatures for 5 different organics namely, water thyme (Drum A), water hyacinth (Drum B), vegetable waste (Drum C), sewage sludge (Drum D) and industrial sludge (Drum E) were done in 550 L rotary drum composter for 20 d in batch-mode. Compost applicability was interpreted on factors like degradation kinetics, physical (BD, FAS, etc.) and nutritional (K, Na, P, etc.) properties along with their interdependency via the statistical route (scatterplot matrix and principal component analysis). High organic matter loss (64%) in Drum B and improved bulk density (756 kg m−3) in Drum A inferred better suitability for soil application. Compost for all the drums (except Drum D) were observed to be well-graded in nature (coefficient of uniformity > 3 and coefficient of curvature ≥ 1) and could be utilized as an “artificial soil” in foundations or embankments to improve the physical characteristics of the soil. Present investigation through multivariate (statistical) approach are imperative to truly master the production of desired compost for both agro and engineering applications.

Recalcitrant carbon for composting of fibrous aquatic waste: Degradation kinetics, spectroscopic study and effect on physico-chemical and nutritional properties

Biochar, a recalcitrant carbon, is known to enhance organic matter degradation and improve physical properties. The objective of the study is to examine the probable effect of biochar addition during composting of a fibrous aquatic waste, i.e., water hyacinth though degradation kinetics and spectroscopic (FTIR and PXRD) analysis. Four dosages of biochar (0, 2.5, 5, and 10% w/w) were mixed to a mixture of water hyacinth, cow-dung and saw-dust comprising a total weight of 150 kg and composted using rotary drum composter for 20 days in batch mode. The study outcomes indicated that the amendment of biochar prolonged the duration of the thermophilic temperatures, reduced salinity, and promoted nutritional quality of compost. Moreover, biochar amendment enhanced the organic matter degradation with a rate constant of 0.029 day−1 and increased the total Kjeldahl nitrogen content up to 1.75% from an initial value of 1.10% in the reactor with 2.5% biochar amendment. Concurrently, biochar amendment aided in reducing Cu and Cr in the final product inferring 2.5% biochar is best suited for composting of water hyacinth. However, future studies are encouraged to decipher the microbial shifts and bioavailability of metals due to biochar dosage during composting for mitigating and managing the menace of such fibrous waste like water hyacinth by converting it to a soil conditioner.

Interplay of physical and chemical properties during in-vessel degradation of sewage sludge

Sewage sludge produced is either applied to land or used as fertilizer for crops or disposed of in landfills, causing several environmental problems. Recent studies revealed that composting is a proven technology in reducing organic content, heavy metals, and harmful pathogens, improving the nutritional value of sewage sludge, which is useful for crops. But studies on variation in physical properties are rare. Composting physics or physical properties during composting plays a vital role from handling, management, and utilization of end product, i.e., compost. This study mainly deals with the detailed information on physics involved during the degradation process, which is crucial for land and geotechnical applications. In the present study, sewage sludge was used as a composting substrate in 550 L in-vessel rotary drum composter. Emphasis was given in deciphering the changes in physical parameters such as bulk density, porosity, and air-filled porosity and few chemical parameters during the composting process. Besides, a relationship between different physical properties during rotary drum composting was investigated statistically. Bulk density was observed to have increased from 643 to 707 kg m−3 as a result of volume reduction of compost matrix. Moreover, the gravimetric moisture content was found to be less than 45% in the end product, which is recommended for compost.