Effect of inoculating flower stalks and vegetable waste with ligno-cellulolytic microorganisms on the composting process

A lab-scale composting experiment was carried out using vegetable and flower stalks waste to study the effectiveness of ligno-cellulolytic microorganisms (LCMs) obtained from the previous isolation on composting process, especially on enhancement of biodegradation rate of these organic materials. The addition of LCMs to compost showed promised to be a valuable asset by rendering timely benefits in efficiency, maturity, and quality of the composting. This was evidenced by a significant increase of temperature, O2 consumption and CO2 emission, and population density of LCMs in compost mass compared with that of biotic (addition of culture of horse feces) and abiotic (1% molasses amendment) treatments, as well as control trial. The phytotoxicity assay showed that the substrate became mature after 60 days' composting. The LCMs inoculation enhanced the biodegradation of the composting materials as evidenced by an increasing screening ratio (1.2 cm sieve pore) of 34.5% in the treated trail, compared with that of control, which elucidated that big advantage of adding selected inoculants over other treatment, and screening ratio is a reasonable index to compare the quality of different compost. However, the inoculation seemed to have no significant effect on the moisture content, pH, and the final organic carbon of the composting materials.     

The addition of modified attapulgite reduces the emission of nitrous oxide and ammonia from aerobically composted chicken manure

The acceleration of the composting process and the improvement of compost quality have been explored by evaluating the efficacy of various additives, inoculating with specific microorganisms and the application of various biosurfactants. The magnesium-aluminum silicate attapulgite is a low-cost potential composting additive, but its effects on aerobic composting are unknown. This study investigated the effects of attapulgite application on compost production and quality during the aerobic composting of chicken manure. Addition of attapulgite significantly increased the temperature (p < 0.05) while it reduced compost total organic carbon (TOC) and seed germination indices (GIs) throughout the process. Its addition enhanced nitrate concentrations, promoted organic matter degradation, increased seed germination indices, and accelerated the composting process. Interestingly, attapulgite addition did not increase the population of ammonia-oxidizing bacteria. These results suggest that attapulgite is a good additive for the composting industry.

Implications: We investigated the addition of two forms of attapulgite during aerobic composting of chicken manure to determine their effects under strict composting environmental parameter control. Our results provides primary evidence that attapulgite may have potential for application in the composting industry.

All treatments showed no increase within the first 15 days. However, emissions increased for all treatments within 15–45 days, reaching approximately 6300, 2000, and 4000 mg/m² from the control, artifactitious attapulgite, and raw attapulgite treatments, respectively.     

Evaluation of microbially enhanced composting of sophora flavescens residues

The effects of inoculants on the composting of Sophora flavescens residues were evaluated based on several physical, chemical and biological parameters, as well as the infrared spectra. Compared to the control compost without inoculants, the treatment compost with inoculants (Bacillus subtilis strain G-13 and Chaetomium thermophilum strain GF-1) had a significantly longer thermophilic duration, higher cellulase activity and a higher degradation rate of cellulose, hemicellulose and lignin (P < 0.05). Thus, a higher maturity degree of compost with apparently lower C:N ratio (15.88 vs. 17.77) and NH₄-N:NO₃-N ratio (0.16 vs. 0.20) was obtained with the inoculation comparing with the control (P < 0.05). Besides, the inoculants could markedly accelerate the composting process and increase the maturity degree of compost as indicated by the germination index (GI) in which the treatment reached the highest GI of 133.2% at day 15 while the control achieved the highest GI of 125.7% at day 30 of the composting. Inoculation with B. subtilis and C. thermophilum is a useful method to enhance the S. flavescens residues composting according to this study.     

添加氮损失抑制剂对蓝藻泥堆肥质量的影响

对脱水蓝藻进行大型生产性堆肥实验。研究堆肥过程中,氮损失抑制剂过磷酸钙的添加对堆肥物料各类理化性质的影响。研究结果表明,过磷酸钙加入的处理组与未加过磷酸钙的对照组堆制37 d后堆肥物料均可腐熟,且堆肥肥效均符合NY525-2002的相关要求。添加过磷酸钙处理组有机质含量为490 g/kg,全N、全P和全K含量分别为20.75、10.02和11.32 g/kg,总养分含量达到9.77%,堆肥品质明显优于对照处理。同时,在微生物的作用下,对照组中微囊藻毒素MC-RR与微囊藻毒素MC-LR去除率分别达到89.8%与78.3%。值得一提的是,添加过磷酸钙后,MC-RR和MC-LR的去除率得到进一步提高,分别达到了92.96%和100%,较好地保证了蓝藻堆肥农用的安全性,为脱水蓝藻好氧堆肥化提供了可行性依据。     

Development of functional composts using spent coffee grounds,poultry manure and biochar through microbial bioaugmentation

Spent coffee grounds (SCG), poultry manure, and agricultural waste-derived biochar were used to manufacture functional composts through microbial bioaugmentation. The highest yield of tomato stalk-based biochar (40.7%) was obtained at 450°C with a surface area of 2.35 m² g^?1. Four pilot-scale composting reactors were established to perform composting for 45 days. The ratios of NH₄⁺–N/NO₃^?–N, which served as an indicator of compost maturity, indicate rapid, and successful composting via microbial bioaugmentation and biochar amendment. Moreover, germination indices for radish also increased by 14–34% through augmentation and biochar amendment. Microbial diversity was also enhanced in the augmented and biochar-amended composts by 7.1–8.9%, where two species of Sphingobacteriaceae were dominant (29–43%). The scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) were enhanced by 14.1% and 8.6% in the fruits of pepper plants grown in the presence of the TR-2 (augmentation applied only) and TR-3 (both augmentation and biochar amendment applied) composts, respectively. Total phenolic content was also enhanced by 68% in the fruits of the crops grown in TR-3. Moreover, the other compost, TR-L (augmentation applied only), boosted DPPH scavenging activity by 111% in leeks compared with commercial organic fertilizer, while TR-3 increased the phenolic content by 44.8%. Composting facilitated by microbial augmentation and biochar amendment shortened the composting time and enhanced the quality of the functional compost. These results indicate that functional compost has great potential to compete with commercially available organic fertilizers and that the novel composting technology could significantly contribute to the eco-friendly recycling of organic wastes such as spent coffee grounds, poultry manure, and agricultural wastes.     

An Investigation of Odors and Volatile Organic Compounds Released during Composting

ABSTRACT

The emissions of odors and volatile organic compounds produced from a commercial composting operation have been studied using a laboratory-scale composting system. The composting activity of a typical commercial compost feed was followed by monitoring the composting temperature, as well as the respiratory rate. Using a controlled aeration system, the gaseous volatiles produced were tested for odors using the "dilution-to-threshold" method, as well as gas composition, as determined by gas chromatography-mass spectrometry.

The results indicated that while there may be a reasonable correlation between the release of volatile organic compounds (VOCs) and odors, care has to be taken when trying to identify offensive odors with specific chemical species. However, the data obtained suggests that offensive odors formed during commercial composting may be due to sulfurous and nitrogenous compounds, although their concentrations in the compost gases may not be very high.

The major release of VOCs occurred during the first two weeks of composting, after which the gaseous releases fell dramatically as the composting process proceeded and temperatures started to fall.     

Effect of inoculation methods on the composting efficiency of municipal solid wastes

Four types of inoculation methods were studied during the composting of municipal solid wastes and dry grass (MSWG). The methods included a control group as well as initial-stage, two-stage, and multi-stage inoculations. Fulvic acids were extracted from the composting materials and characterized by spectroscopic techniques. The results showed that inoculation of microbes in MSWG enhanced the biodegradation of aliphatics, proteins, and polysaccharides. The inoculation also increased the molecular weight, humic- and fulvic-like compound content, as well as humification degree of the composting products. The inoculation of microbes in MSWG significantly improved composting process and efficiency. The improvement efficiency was in the order of initial-stage < two-stage < multi-stage inoculations. Inoculation of microbes based on composting organic matter composition and temperature enhanced composting efficiency.     

Evaluating Environmental Parameters for Minimum Ammonium Losses during Composting of Trimming Residues

Abstract

A neural fuzzy system was used to investigate the influence of environmental variables (time, aeration, moisture, and particle size) on composting parameters (pH, organic matter [OM], nitrogen [N], ammonium nitrogen [NH₄ ⁺-N] and nitrate nitrogen [NO₃ ^--N]). This was to determine the best composting conditions to ensure the maximum quality on the composts obtained with the minimum ammonium losses. A central composite experimental design was used to obtain the neural fuzzy model for each dependent variable. These models, consisting of the four independent process variables, were found to accurately describe the composting process (the differences between the experimental values and those estimated by using the equations never exceeded 5–10% of the former). Results of the modeling showed that creating a product with acceptable chemical properties (pH, NH₄ ⁺-N and NO₃ ^--N) entails operating at medium moisture content (55%) and medium to high particle size (3–5 cm). Moderate to low aeration (0.2 L air/min · kg) would be the best compromise to compost this residue because of the scant statistical influence of this independent variable.     

Mitigation of odor causing emissions—Bench-scale investigation

Emissions of malodors are considered to be the greatest threat to the compost industry. In work presented here, several simple odor mitigation alternatives were investigated for their effectiveness in preventing the release of common odorants, such as terpenes, ammonia, and reduced sulfur compounds. The mitigation methods studied included the use of a blanket of finished compost, compost amendment mixed within the feedstock, odor neutralizing agents (ONAs), and oxygen release compounds (ORCs). Among the mitigation alternatives investigated in this study, the use of finished compost as a blanket and finished compost as an amendment yielded the most conclusive and significant results. Both of these alternatives yielded a substantial emission reduction for terpenes, ammonia, and reduced sulfur compounds. The application of finished compost blanket resulted in up to 95% reduction of terpene and 25% reduction of ammonia emissions. Blending the feedstock with finished compost also provided substantial reduction of terpene emissions ranging from 73.6 to 93.1% at the 24% blending ratio, and up to 85% ammonia reduction a the 35% blending ratio. Use of finished compost also provided 75% lower reduced sulfur compound emissions at the 12% blending ratio. Misting and application of odor neutralizing agents did not result in any consistent reduction in emissions for any of the odorous compounds tested.

Implications The odor emissions from composting are often considered to be the biggest threat to composting facilities. Because most facilities cannot afford enclosures and contained composting vessels, there is a need to inexpensively and effectively control the odor emissions from composting facilities. The findings of this research can lead the way for efforts to control odor easily and cost effectively. In fact, the application of a compost blanket for odor control is already gaining acceptance by the composting industry.     

Co-composting of Paper Mill Sludge and Hardwood Sawdust Under Two Types of In-Vessel Processes

Abstract

Recycling of organic residues by composting is becoming an acceptable practice in our society. Co-composting dewatered paper mill sludge (PMS) and hardwood sawdust, two readily available materials in Canada, was investigated using uncontrolled and controlled in-vessel processes. The composted materials were characterized for total C and N, water-soluble, acid-hydrolyzable, and non-hydrolyzable N, extractable lipids, and by Fourier Transform Infrared (FT-IR) spectrophotometry. In the controlled scale process, the loss of organic matter was approximately 65% higher than in the uncontrolled process. After undergoing initial fluctuations in N fractions during the first two days of composting, by the end of the process, concentrations of water-soluble N decreased while those of acid-hydrolyzable and nonhydrolyzable N increased in the controlled process, whereas in the uncontrolled process, water-soluble N increased, but N in the other two fractions decreased continuously, indicating that the biochemical transformations of organic matter were not completed. Data on extractable lipids and FT-IR spectra suggest that the compost produced from the controlled process was bio-stable after 14 days, while the uncontrolled process was not stabilized after 18 days. In addition, FT-IR data suggest the biological activity during composting centered mainly on the degradation of aliphatic structures while aromatic structures were preserved. The co-composting of the PMS and hardwood sawdust can be successfully achieved if aeration, moisture, and bio-available C/N ratios are optimized to reduce losses of N.     

接种外源微生物菌剂对香蕉茎秆堆肥的影响

为了研究接种外源微生物菌剂对香蕉茎秆堆肥的影响,本实验采用高温好氧堆肥技术,设计了对照（不接菌）、接种白腐菌及棱盖多孔菌3个处理,探讨了不同处理堆肥过程中堆体温度、水分、pH值、电导率、有机碳、C/N、发芽指数及堆肥质量的变化情况。结果表明,接种微生物菌剂处理的温度均高于对照,且高温期持续时间相对较长,以接种白腐菌处理的高温持续时间最长;接种外源微生物菌剂对堆肥含水率、pH、EC、全碳、C/N变化影响不大;与对照相比,接种白腐菌可增加全氮及全钾的含量,有利于提高堆肥产品质量;接种白腐菌处理在36 d（GI〉50%）就达到腐熟,比对照提前8 d腐熟,明显缩短堆肥腐熟时间;而接种棱盖多孔菌处理比对照推迟10 d腐熟,共需54 d不利于香蕉茎秆堆肥的进行。     

The Fate of the Recombinant DNA in Corn During Composting

Abstract

In order to make regulations that safeguard food and the environment, an understanding of the fate of transgenes from genetically modified (GM) plants is of crucial importance. A compost experiment including mature transgenic corn plants and seeds of event Bt 176 (Zea mays L.) was conducted to trace the fate of the transgene cryIA(b) during the period of composting. In bin 1, shredded corn plants including seeds were composted above a layer of cow manure and samples from the corn layer were collected at intervals during a 12-month period. The samples were tested for the transgene persistence and microbial counts and also the compost was monitored for temperature. In bin 2, piles of corn seeds, surrounded by sheep manure and straw, were composted for 12 months. A method combining nested polymerase chain reaction (PCR) and southern hybridization was developed for detection of the transgene in compost. The detection sensitivity was 200 copies of the transgene per gram of dry composted corn material. Composting commenced on day 0, and the transgene was detected in specimens from bin 1 on days 0 and 7 but not on day 14 or thereafter. The transgene in corn seeds was not detectable after 12 months of composting in bin 2. Temperatures in both bins rose to about 50°C within 2 weeks and remained above that temperature for about 3 months, even when the ambient temperature dropped below ?20°C. Extracts from compost were inoculated onto culture plates and then were incubated at 23 to 55°C. Within the first 2 weeks of composting in bin 1, the counts of bacteria incubated at 55°C increased from 3.5 to 7.5 log ₁₀, whereas those incubated at 23°C remained at about 7.5 log ₁₀. The counts of fungi incubated at 45°C increased slightly from 2.5 to 3.1 log₁₀, but those incubated at 23°C decreased from 6.3 to 3.0 log ₁₀. The rapid degradation of the transgene during composting of Bt corn plants suggested that the composting process could be used for safe disposal of transgenic plant wastes.     

The use of elemental sulphur as organic alternative to control pH during composting of olive mill wastes

High values of pH may represent a limitation for the agricultural use of the composts, not only when used as soil-less substrate but also as soil amendment in high pH soils. The addition of elemental S during the maturation phase of the composting process was evaluated as suitable method to reduce pH of the composts under the organic agriculture regulations. A compost prepared with two phase olive mill waste (OMW) and sheep litter (SL) was used to study the effect of elemental sulphur addition on the pH of the composting mixture. Initially, different bench scale experiments were designed in order to study the influence of moisture, sulphur concentration, and incubation temperature on the sulphur oxidation rate and thus on the pH of the compost. A concentration of 0.5% in sulphur (dry weight basis) and moisture of 40% were proposed as the optimum conditions to decrease the compost pH by 1.1 units without increasing in EC to levels that may suppose a limitation for its agricultural use. Finally, these optimum experimental conditions found at bench scale were tested at full scale in a commercial composting plant treating the same organic materials by windrowing. The pH values of the composting mixture were reduced by one unit after 2 weeks following the addition of elemental S causing no negative effects on the final compost quality.     

Influences of adding easily degradable organic waste on the minimization and humification of organic matter during straw composting

To find a better composting process with low greenhouse gas emission and high humus production, the effect of adding kitchen waste on reduction and humification of organic matter during straw composting was studied. Three processes were compared, consisting of different ratios of straw and kitchen waste (1:2, 1:1, and 2:1). At four time points over a 62-d incubation, the reduction and humification of compost was evaluated by measuring the total mass, carbon content, and humic material content of the compost. Treatment 1 (straw/kitchen waste ratio of 1:2) reduced the total mass of compost the most. Treatment 2 (straw/kitchen waste ratio of 1:1) reduced the total carbon content the most, reflecting the highest emission of greenhouse gas. Treatment 3 produced the most humic acid material and released the lowest amount of carbon. Hence, from the point of view of reducing greenhouse gas emissions and increasing stable organic matter such as humus and humic acid during composting, treatment #3 was optimal. The three treatments resulted in significant differences in microbial biomass and enzyme activity during composting. The highest amount of active microbial biomass was associated with the largest reduction in compost mass (treatment 1). Higher proportions of straw (treatments 2 and 3), which contains more lignin, were associated with greater β-glycosidase activity, which may generate more humus that can improve soil quality. Dehydrogenase activity seemed to be the most important microbial factor in organic carbon catabolism or humification.     

Thermophilic Toluene Biofiltration

ABSTRACT

Thermophilic biodégradation of toluene with active compost biofilters was studied. Thermophilic conditions were maintained either by daily substrate addition (semicontinuous composting) or with a heating system (batch thermophilic composting). The semicontinuous system was designed for the treatment of cool (less than approximately 35 °C) gases under thermophilic conditions, while the extended batch approach was developed for the treatment of warmer gases. When the semicontinuous system was operated at 50 °C (after a one-day start-up period) at an average inlet concentration of 5.5 g m^-3, toluene was degraded at a rate ranging from 73 to 110 g C m^-3 hr^-1. Batch thermophilic treatment was somewhat less effective at the same inlet concentration. Semicontinuous toluene biofiltration at 60 °C was also investigated, but biodegradation rates were significantly lower than at 50 °C. In all systems, toluene biodegradation was proportional to the inlet concentration. Rates of up to 289 g C m^-3 hr^-1 (at an inlet concentration of 14.7 g m^-3) were achieved for semicontinuous and batch operation and 251 g C m^-3 hr^-1 (at an inlet concentration of 18.4 g m^-3) for batch thermophilic at 50 °C. Semicontinuous thermophilic operation at 60 °C showed a maximum rate of 119 g C m^-3 hr^-1. Active compost ther-mophilic biofiltration was found to be very effective when concentrations are high. At lower concentrations, rates were similar to those obtained with mesophilic biofiltration. Mixing, humidity, and the presence of cosubstrate were important parameters in maintaining high degradation rates. Biofiltration in the batch thermophilic mode could be useful when conventional biofiltration is ineffective due to elevated gas temperatures. Biofiltration in the semicontinuous thermophilic could reduce the biofilter size necessary for treatment of cooler gases containing high concentrations of volatile organic compounds.     

Oxidative biodegradation of dissolved organic matter during composting

Dissolved organic matter (DOM) plays an important role in the microbial degradation of compost since it represents the most active organic fraction, both biologically and chemically. The detailed evaluation of the changes in the chemical and biochemical characteristics of DOM induced by oxidative biodegradation, presented in this work highlights the mechanisms involved in the degradation of soluble organic matter during composting. In fact, the results show that during the initial stages of composting, DOM is highly degradable under aerobic conditions, particularly due to the predominance of labile, hydrophilic compounds such as carbohydrates, amino acids and proteins. As such compounds are degraded more resistant aromatic moieties accumulate in solution resulting in a reduction in the degradability of DOM with composting time. This decrease in degradability was found to be highly correlated with microbial oxygen demand, and could have important implications in the evaluation of the composting process.     

Effects of different ratios of pig manure to fungus residue on physicochemical parameters during composting

This study examined physicochemical parameters to assess their effectiveness as stability and maturity indicators during the process of composting pig manure and fungus residue at different ratios. The results showed that composting mixtures with all ratios of pig manure to fungus residue maintained a temperature exceeding 50 °C for more than 10 days during composting and met the requirement for pathogen destruction. The treatment containing mainly pig manure showed higher nitrogen loss and a shorter thermophilic phase and maturity time than the treatment containing mainly fungus residue. The germination index (GI) values indicated that compost maturity was achieved in the final compost with initial ratios of pig manure to fungus residue of 9:1–7:3 (GIs of 101.4%, 91.2%, and 81.3%); the ratio of 6:4 did not reach compost maturity (GI of 63.8%) and had an inhibitory effect on seed germination. The results of this study suggest that a ratio of pig manure to fungus residue of approximately 8:2 can be considered suitable for the efficient and quality composting of pig manure and fungus residue.

Implications: Co-composting of pig manure and edible fungi residue with appropriate proportion can effectively reduce the risk of environmental pollution caused by agricultural wastes, as well as achieve a safer and high-quality organic fertilizer, which can be used to improve physical and chemical properties of the soil, increase crop yields, and promote agricultural sustainable development. Therefore, technique of co-composting of pig manure and edible fungi residue has a wide prospect of application in practical production all over the world.     

Co-composting of spent coffee ground with olive mill wastewater sludge and poultry manure and effect of Trametes versicolor inoculation on the compost maturity

The co-composting of spent coffee grounds, olive mill wastewater sludge and poultry manure was investigated on a semi-industrial scale. In order to reduce the toxicity of the phenolic fraction and to improve the degree of composting humification, composts were inoculated with the white-rot fungus Trametes versicolor in the early stages of the maturation phase.During composting, a range of physico-chemical parameters (temperature and both organic matter and C/N reduction), total organic carbon, total nitrogen, elemental composition, lignin degradation and spectroscopic characteristics of the humic acids (HAs) were determined; impacts of the composting process on germination index of Hordeum vulgare and Lactuca sativa were assessed. The coffee waste proved to be a highly compostable feedstock, resulting in mature final compost with a germination index of 120% in less than 5 months composting. In addition, inoculation with T. versicolor led to a greater degree of aromatization of HA than in the control pile. Moreover, in the inoculated mixture, lignin degradation was three times greater and HA increased by 30% (P < 0.05), compared to the control pile. In the T. versicolor inoculated mixture, the averages of C and N were significantly enhanced in the HA molecules (P < 0.05), by 26% and 22%, respectively. This improvement in the degree of humification was confirmed by the ratio of optical densities of HA solutions at 465 and 665 nm which was lower for HA from the treated mixture (4.5) than that from the control pile (5.4).     

Bioaerosol Generation at Large-Scale Green Waste Composting Plants

Abstract

Bioaerosol release from composting plants is a cause of concern because of the potential health impacts on site workers and local residents. A one-year monitoring was undertaken in a typical composting plant treating green wastes by windrowing in the open. Aspergillus fumigatus spores and mesophilic bacteria were used as monitoring parameters and were collected in a six-stage Andersen sampler impactor from the air at different locations and during different operational activities. Background concentrations of both microorganisms were generally below 1000 colony-forming units m^?3 when no vigorous activity was taking place. Shredding of fresh green wastes, pile turning, and screening of mature compost were identified as the activities generating the highest amounts of both bioaerosols 40 m downwind of the composting pad. These air concentrations were ～2 log units higher than background levels. Screening of mature compost generated lower amounts of A. fumigatus than the other two activities (an average of 1 log unit higher than background levels). Workers were identified as the main potential receptors of high bioaerosol concentrations in areas close to the composting pad, whereas no major risk for local residents was expected because the concentrations recorded at distances of 200 and 300 m downwind of the operational area were not significantly different from background levels.     

Influence of aeration rate and reactor shape on the composting of poultry manure and sawdust

To achieve successful composting, all the biological, chemical, and physical characteristics need to be considered. The investigation of our study was based on various physicochemical properties, i.e., temperature, ammonia concentration, carbon dioxide concentration, pH, electrical conductivity (EC), carbon/nitrogen (C/N) ratio, organic matter (OM) content, moisture content, bacterial population, and seed germination index (GI), during the composting of poultry manure and sawdust for different aeration rates and reactor shapes. Three cylindrical-shaped and three rectangular-shaped pilot-scale 60-L composting reactors were used in this study, with aeration rates of 0.3 (low), 0.6 (medium), and 0.9 (high) L min^?1 kg^?1 DM (dry matter). All parameters were monitored over 21 days of composting. Results showed that the low aeration rate (0.3 L min^?1 kg^?1 DM) corresponded to a higher and longer thermophilic phase than did the high aeration rate (0.9 L min^?1 kg^?1 DM). Ammonia and carbon dioxide volatilization were directly related to the temperature profile of the substrate, with significant differences between the low and high aeration rates during weeks 2 and 3 of composting but no significant difference observed during week 1. At the end of our study, the final values of pH, EC, moisture content, C/N ratio, and organic matter in all compost reactors were lower than those at the start. The growth rates of mesophilic and thermophilic bacteria were directly correlated with mesophilic and thermophilic conditions of the compost. The final GI of the cylindrical reactor with an airflow rate of 0.3 L min^?1 kg^?1 DM was 82.3%, whereas the GIs of the other compost reactors were below 80%. In this study, compost of a cylindrical reactor with a low aeration rate (0.3 L min^?1 kg^?1 DM) was more stable and mature than the other reactors.

Implications: The poultry industry is growing in South Korea, but there are problems associated with the management of poultry manure, and composting is one solution that could be valuable for crops and forage if managed properly. For high-quality composting, the aeration rate in different reactor shapes must be considered. The objective of this study was to investigate various physicochemical properties with different aeration rates and rector shapes. Results showed that aeration rate of 0.3 L min^?1 kg^?1 DM in a cylindrical reactor provides better condition for maturation of compost.