• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.69-84
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• 1993

In order to determine the optimum operational paramsters in cow manure composting, 4 laboratory scale composters were established. The cow manure was mixed with certain amount of saw dust to adjust the initial C/N ratio to 24, initial pH to 6.9 and composting was performed with varying operational conditions. It was found that the optimum aeration rate was 1000 ml/min kg. VS, the optimum moisture content 50% and no significant difference was found with different initial pH condition. Microorganisms were counted under the optimum conditions determined in this study. At the end of the experimental period, the number of bacteria, actinomycetes and fungi was $1.5{\times}10^9$ cells, $1.1{\times}10^8$ cells and $3.0{\times}10^8$ cells/g dry compost, respectively. At day 0, the number of coliforms, fecal coliforms and fecal streptococci was $3.1{\times}10^3$ cells, $7.5{\times}10^2$ cells and $5.6{\times}103$ cells/g dry composting material, respectively. Their population was decreased with time lapse, However, their survival time was longer than those reported by other researchers. Microorganisms were identified at the end of the experiment. Genus Bacillus was the most dominant comprising 89.3% of the total population. Among the Genus Bacillus, B. circulans compoex was the most abundant, followed by B. Stearothermophilus, B. Sphericus, B. licheniformis and B, brevis.

• Journal of the Korea Organic Resources Recycling Association
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• v.5 no.1
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• pp.15-23
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• 1997

Commercial inocula and mature compost were added separately to food wastes in order to compare the inoculating effect on garbage decomposition. Among commercial inocula available in the market, GM (Green Microorganisms) and EM (Effective Microorganisms) were selected as test inocula. Garbage decompostion were evaluated in Volatile Solid (VS) reduction and FDA (Fluorescein DiAcetate) hydrolysis activity. VS reduction with mature compost experiment was higher than that with GM-added one. VS reduction rates were about 32% with mature compost and 27% with GM. When food wastes were treated with GM and EM based on the manufacturer's specifications, GM-added and EM-added food wastes showed only 8% and 9% of VS reduction respectively, which are much lower than those with the mature compost. FDA hydrolysis activity increased during the first 10 days of active composting periods for the composting experiments, while it decreased continuously for the experiments based on manufacturer's specifications.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.89-96
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• 2000

Waste oyster shell was used to study the applicability on anaerobic composting of garbage. Experiment was conducted with five anaerobic reactors. After garbage and compost for inoculation were mixed, waste oyster shell was added into mixed waste in mesophillic temperature for 60 days with 30%, 60% respectively. The amount of produced methane gas, gas composition, organic removal efficiency and pH were measured. Result showed that the amounts of produced gas were 0.62 l /g-VS in R-1, 0.63 l /g-VS in R-2, 0.16 l /g-VS in R-3, 0.75 l /g-VS in R-4, 0.21 l /g-VS in R-5 and the amounts of produced methane gas were 0.32 l /g-VS in R-1, 0.37 l /g-VS in R-2, 0.04 l /g-VS in R-3, 0.42 l /g-VS in R-4, 0.05 l /g-VS in R-5. Proportion of mathane gas which determines the efficiency of anaerobic composting was over 55%. pH were 6.0~8.0 in R-2 and R-4 which contained 30% of waste oyster shell and pH were increased over 8.5 in R-3 and R-5 which contained 60% of waste oyster shell. Since pH were so high and it had a negative effect on microbial growth, anaerobic reaction were not well operated in R-3 and R-5.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.1
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• pp.43-52
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• 1999

This study was carried out to investigate how much coal fly ash could be substituted for sawdust as a bulking agent for livestock waste composting. The mixtures of coal fly ash and sawdust in the weight ratio of 8 to 2, 7 to 3, 6 to 4, 5 to 5, 4 to 6, 3 to 7 and 2 to 8 were added to livestock waste as the bulking agent. The same amount of the bulking agents and livestock waste was mixed and composted during 21 days. Following effects were analyzed during composting experiment : the variation of temperature, pH and various compound contents. The results were summarized as follows: The more the sawdust was added, the higher the maximum temperature in slurry type livestock farm but faster it reached in scrapper type. Water content was maintained under good condition by adding the bulking agent mixed of the same amount of coal fly ash and sawdust. pH was in the range of 7~10 by adding the bulking agent mixed of the same amount of coal fly ash and sawdust. The more the sawdust was added, the higher organic matter content was measured. Nitrogen content with increasing the amount of sawdust added but it was higher did not showed any tendency Organic matter/Nitrogen ratio reduced during the composting period in scrapper type but it showed contrary tendency in slurry type with that of scrapper type.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.335-340
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• 2010

This study was conducted to select organic materials (OM) and nitrogen sources in composting of waste mushroom bed from Agaricus bisporus. We examined physio-chemical properties of the organic materials and the mixture ratio for preparing the wasted mushroom bed (M) compost. The carbon content of sawdust was higher than those of rice straw (R) as OM source and the nitrogen content was high in the order of fowl manure (F)>> pig manure (P)> cow manure (C). The compost was prepared to maintain the criteria of above 25% organic matter and then the change of their ingredients was estimated during the process of fermentation. The temperature of waste mushroom bed+pig manure+rice straw (MRP) treatment was varied fast throughout fermentation, on the other hand the temperature of waste mushroom bed+pig manure+sawdust (MSP) treatment was steadily elevated to the middle of composting. The pH of the compost was somewhat high to pH 8.5~9.0 at the early stage, but decreased to 7.5 at the end stage of composting. The content of OM after fermentation was decreased to the level of 19~21% in rice straw, but the sawdust treatment maintained 25~27% organic matter. The waste mushroom bed+fowl manure+rice straw (MRF) treatment, which contains 26.2% organic matter and 0.68% nitrogen, was the highest among them. The volume of compost was reduced to 50% by using rice straw as organic matter, but reduced to 30% by using the sawdust. The contents of heavy metal in the compost were suitable within the legal criteria. The number of microorganisms were higher in the rice straw than those in the sawdust. It was high in the order of fowl manure> pig manure> cow manure. The major groups consisted of aerobic bacteria, gram negative bacteria and Bacillus sp. and their populations after fermentation were increased to $1{\times}10^1{\sim}1{\times}10^2\;cfu\;g^{-1}$ rather than those before fermentation. Therefore we concluded that the waste mushroom bed+fowl manure+sawdust (MSF 3:9:1 v/v/v) treatment was suitable combination for high organic matter and nitrogen source, and the periods of composting were 50~60 days.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.472-481
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• 2000

This experiment used the enclosed bench-scale reactors was conducted to find out optimal aeration rate for reducing the emission of odors and producing the good-quality compost with the mixture of dairy manure and rice straw. The reactors with gas sampler were aerated at four different rates of 0.09, 0.18, 0.90 and $1.79l\;min^{-1}kg^{-1}$dry solids for 574 hours. The oxygen content within composting pile instantly decreased after aeration. Oxygen limitation(below 15%) in the treatments of $0.90l\;min^{-1}kg^{-1}$ and less was exponentially negative relationship with aeration rates and in the range of 35 to 300 hours after aeration. However, the treatment of $1.79l\;min^{-1}kg^{-1}$ didn't show the oxygen limitation. The oxygen consumption rate and the cumulative amount of oxygen consumed by different aeration rates was ranged in $0.80{\sim}1.57O_2g\;h^{-1}\;kg^{-1}VS^{-1}$, $460{\sim}900O_2g\;kg^{-1}VS^{-1}$, respectively, and they were high in the order of 0.90, 1.79, 0.18, $0.09l\;min^{-1}kg^{-1}$. The maximum oxygen consumption rate was estimated in the range of $1.2{\sim}1.3lmin^{-1}kg^{-1}$. The emission concentrations of sulfur compounds such as hydrogen sulfide, sulfur dioxide and methylmercaptan were remarkably high in the initial composting time. Then they were rapidly decreased with the passing of composting time and clearly with increasing aeration rates. Their average concentrations were in the range of 0.03~2.18, 0~0.50, $0.07{\sim}3.38mg\;kg^{-1}$, respectively and high in the order of methylmercaptan, hydrogen sulfide, and sulfur dioxide. Concentrations of sulfur compounds emitted from composting showed exponentially negative relationship at 1% statistically with the oxygen concentration. It was estimated that hydrogen sulfide and methylmercaptan suddenly increased in the level of 5% oxygen concentration and below, that they were little emitted in 15% and over but sulfur dioxide was emitted in the level of 20% oxygen.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.397-402
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• 2006

The treatment characteristics of leachate produced from pretreatment facilities like composting and feeding were investigated in a mesophilic anaerobic treatment. Experiments were performed in two phase which were acidification and methane fermentation. The acidification step was optimized for OLR from 1 to $4.5kg\;COD/kg\;VS{\cdot}day$ without adding NaOH. As experiment dates became longer, the solubilization ratio of particles increased up to 30% over 70 days. TVA was generated up to maximum 9,970mg HAc/L at OLR of $2kg\;COD/kg\;VS{\cdot}day$. But TVA was generated to minimum 6,519mg HAc/L at OLR of $4.5kg\;COD/kg\;VS{\cdot}day$. The acidification ratio was analyzed from 10.9% to 3.8% at OLR of $2kg\;COD/kg\;VS{\cdot}day$ and $4.5kg\;COD/kg\;VS{\cdot}day$ respectively. After 55 days, salt contents in the acid fermenter were accumulated and stabilized at the concentration of 3,150mg/L. Sodium ion($Na^+$) concentration was stabilized at 1,300mg/L. At methane fermentation step, biogas was generated up to 750ml and 937.5ml at the feeding volume of 20ml and 25ml respectively for acid fermented liquid during 25 days. About 80% of total biogas was generated during early 15 days and 95% were generated during 18 days respectively. After 25 days of the BMP test, acetic acid was removed approximately 97% and 98%, in case of those two experimental conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.5
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• pp.763-772
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• 2018

Objective: Swine manure in Korea is separated into solid and liquid phases which are composted separately and then applied on land. The nutrient accumulation in soil has been a big issue in Korea but the basic investigation about nutrient input on arable land has not been achieved in detail. Within the nutrient production from livestock at the national level, most values are calculated by multiplication of the number of animals with the excreta unit per animal. However, the actual amount of nutrients from swine manure may be totally different with the nutrients applied to soil since livestock breeding systems are not the same with each country. Methods: This study investigated 15 farms producing solid compost and 14 farms producing liquid compost. Composting for solid phase used the Turning+Aeration (TA) or Turning (T) only methods, while liquid phase aeration composting was achieved by continuous (CA), intermittent (IA), or no aeration (NA). Three scenarios were constructed for investigating solid compost: i) farm investigation, ii) reference study, and iii) theoretical P changes (${\Delta}P=0$), whereas an experiment for water evaporation was conducted for analyzing liquid compost. Results: In farm investigation, weight loss rates of 62% and 63% were obtained for TA and T, respectively, while evaporation rates for liquid compost were 8.75, 7.27, and $5.14L/m^2{\cdot}d$ for CA, IA, and NA, respectively. Farm investigation provided with the combined nutrient load (solid+liquid) of VS, N, and P of 117.6, 7.2, and $2.7kg/head{\cdot}yr$. Nutrient load calculated from farm investigation is about two times higher than the calculated with reference documents. Conclusion: The nutrient loading coefficients from one swine (solid+liquid) were (volatile solids, 0.79; nitrogen, 0.53; phosphorus, 0.71) with nutrient loss of 21%, 47%, and 29%, respectively. The nutrient count from livestock manure using the excretion unit has probably been overestimated without consideration of the nutrient loss.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.2
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• pp.227-235
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• 1993

This study was carried out to evaluate the possibility of composting for organic solid waste from restaurants and domestics. Small three vessels were prepared which were conditioned to semianaerobic, convectional and air-blowed type. During the experiment period for 4 months, the values of volatile solid(VS) %, moisture % and carbon/nitrogen (C/N) ratio of the wastes in the vessels were stabilized, 80 % to 40-50 %, 80 % to 48-55 % and 18 to 8-10, respectively. On the basis of VS % and C/N ratio, the reactions were more adaptable to 2nd order formula than to 1st order one, Reaction rate constant of the 3 vessels were estimated, $4.96{\times}10^{-5}(day^{-1})$ in the semianaerobic type, $5.82{\times}10^{-5}(day^{-1})$ in the convectional type and $8.42{\times}10^{-5}(day^{-1})$ in the air-blowed type on VS. Compared reaction rate constants(k), it can be said that composting period shorten if air is supplied artificially and that vessels simular to those of this study are useful for household organic waste at the backyards.

• Environmental Engineering Research
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• v.23 no.1
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• pp.46-53
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• 2018

This study explores the environmentally innovative and low-impact technology, a zero food waste system (ZFWS) that utilizes food waste and converts it into composts or biofuels and curtails carbon emissions. The ZFWS not just achieves food waste reductions but recycles food waste into fertilizer. Based on a fermentation-extinction technique using bio wood chips, the ZFWS was employed in a field experiment of the system installed in a large-scale apartment complex, and the performance of the system was examined. The on-site ZFWS consisted of three primary parts: 1) a food waste slot into which food waste was injected; 2) a fermentation-extinction reactor where food waste was mixed with bio wood chips made up of complex enzyme and aseptic wood chips; and 3) deodorization equipment in which an ultraviolet and ozone photolysis method was employed. The field experiment showed that food waste injected into the ZFWS was reduced by 94%. Overall microbial activity of the food waste in the fermentation-extinction reactor was measured using adenosine tri-phosphate (ATP), and the degradation rate of organic compounds, referred to as volatile solids, increased with ATP concentration. The by-products generated from ZFWS comply with the national standard for organic fertilizer.