• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.1
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• pp.97-102
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• 2000

This study was carried out to investigate the effects of operating temperatures on decomposition and physicho-chemical properties of household food wastes in a fermentation dryer, which was manufactured by Samwoo Co. Ltd. The household food wastes of 100 kg can be put and dried in this dryer at once. The experiments were performed at each temperature of $35^{\circ}C$, $45^{\circ}C$, $55^{\circ}C$ and $70^{\circ}C$ for two days respectively. The samples taken at the fixed time were dried at $105^{\circ}C$ and analyzed to find the decomposition rate and the concentration of each substance. The results obtained were as follows: The decomposition rate at 35 and $70^{\circ}C$ was the highest and showed the similar tendency during the experimental period. The higher the operating temperature was, the faster the water content of the composting material reduced. pH value increased at the operating temperature of 55 and $70^{\circ}C$ and was higher than at the other operating temperatures. Nitrogen content did not show any tendency during the experimental period. $P_2O_5$ and CaO content increased during the experimental period but MgO, $K_2O$ and NaCl were not accumulated. Cu content based on dry matter was in the range of ND~100.4 mg/kg and Cd, Pb and Cr were not detected.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.1
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• pp.77-82
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• 2000

Seven constructed and three natural tidal flats were compared to evaluate state-of- the-art of creation and restoration technology for tidal flats. parameters studied were physico-chemical and biological characteristics of soils and rate of respiration. The natural tidal flats had higher contents of silts, nitrogen and organic matter compared to the constructed ones. The natural ones had reductive Bone below 2 cm whereas the constructed ones had oxidative zone from the surface to below 20 cm. The bacterial population in the soil of the constructed tidal flats was one to two magnitudes lower than that in the natural ones. Biomass of macrobenthos and microbial respiration rate, however, were not different significantly between the natural and the constructed tidal flats. The purification capacity by diatom+bacterial+meiobenthos and macrobenthos in the constructed tidal flats was higher than that in the natural ones due to deeper permeable layer for purification in the constructed tidal flats. There was an exceptional constructed tidal flat with similar physico-chemical and biological characteristics to natural ones. Shearing stress to the surface of the tidal flat by the flow of seawater was as low as that of natural ones. These hydraulic conditions seemed to be a controlling factor on structures and functions of tidal flats. The control of hydraulic condition seemed to be one of the most important factors to create natural-like tidal flats.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.2
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• pp.39-51
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• 1994

When broiler litter was composted under the control of peak temperature of piles(uncontrolled, controled below $70^{\circ}C$ and below $60^{\circ}C$), changes of physical and chemical parameters were determined throughout the processing period. Broiler litter was composted in each of three $1.0{\times}1.0{\times}1.2m$ dimensional facilities for 8 weeks. After 5 to 6 weeks of composting, broiler litter was converted into the final compost with no ammonia odour, rice hull size of particle, and faint brown color. Central temperature of piles reached to the peak(about $69{\sim}70^{\circ}C$) within 3 to 4 days after composting and gradually decreased thereafter. The final product contained 26.5% of moisture, 9.0~9.1 of pH, and 14.0~14.3 of C/N ratio. The increase of C/N ratio with processing resulted from the considerable loss of N. The total wet weight of the final composts was an average of 38.3% of the initial weight, the dry weight of those 64.1%, and the organic matter weight of those 34.8%. Treatments of central temperature of composts did not affect changes of moisture, pH, C/N ratio, total wet weight, total dry weight, and total organic matter weight. In general, composted broiler litter was converted into the final product with little change in physical and chemical parameters after 5 to 6 weeks of processing. Nitrogen losses during the composting should be prevented for the improvement of the composting efficiency of broiler litter.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.1
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• pp.61-70
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• 2012

Feasibility of co-digestion was investigated by a series of anaerobic batch experiments using sewage sludge, swine waste, and food waste leachate as substrates. The organic solid wastes were collected from M city, where the daily productions of sewage sludge, swine waste, and food waste leachate were 178 ton/d, 150 ton/d, and 8 ton/d, respectively. Both swine waste and food waste leachate showed superior methane yields, methane productivities, and organic pollutant removal efficiencies compared to sewage sludge. Co-digestion of the total amounts of organic solid wastes would enhance methane production by 5.60 times $(530\;m^{3}\;CH_{4}/d\;{\rightarrow}\;2,968\;m^{3}\;CH_{4}/d)$. However, it also increase the amount of digestate by 1.88 times with 3.79 to 4.92 times higher pollutants (chemical oxygen demands total nitrogen, and total phosphorus) loading rates. Co-digestion of organic solid wastes is a valid strategy to enhance the performance of an anaerobic sludge digester and the energy independence of a wastewater treatment plant. Anyhow,the increment of digestate with higher pollutant loading would need a careful counterplan in the operation of the main stream of the treatment plant.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.2
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• pp.63-70
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• 2013

Experiments in a pilot-scale hybrid multi-stage unit system (HMUS) combination of ATAD and EGSB followed by SBR process for pig slurry treatment were conducted to demonstrate the feasibility of using autothermal thermophilic aerobic digestion (ATAD) and expended granular sludge bed (EGSB) followed by sequencing batch reactor (SBR) system. Contaminants in pig slurry with high organic matter, nitrogen (N) and phosphorus (P) content were completely removed in the combined process. The highest removal rate for CODcr among contaminants in the feed pig slurry was attained by about 43.3% in ATAD unit process. Also TS removal rate of 96.5% was attained and the highest in the next coagulation unit process. The highest removal rate of CODcr under operating parameter conditions of OLR(organic loading rate), 3-6Kg $COD/m^3{\cdot}day$ and line velocity, 1.5-4m/h was earned at 3days of HRT. The disinfection of pathogens was effective at 50,000mg/L of TS in ATAD unit process. Biogas production per organic removal was $2.3{\sim}8.5m^3/kgTS{\cdot}d$ (average $5.2m^3/kgTS{\cdot}d$) in EGSB unit process. The average removal rates of CODcr 71.7%, TS 64.1%, TN 45.9%, and TP 50.4% were earned in the intermittent aeration SBR unit process.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.91-99
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• 2016

The objective of this study was to investigate characteristics of inorganic components contained in liquid fertilizer produced using fish meal under different condition. Addition of dry yeast to liquid fertilizer resulted in considerable change in pH and electrical conductivity(EC) value compared to other liquid fertilizers which have microorganisms additives. In addition, it was appeared that the dry yeast-added treatment had higher $NH_4-N$ concentration than other treatments. Addition of molasses resulted in low pH compared to the control which has no additives. The EC, concentration $NH_4-N$ and $P_2O_5$ were not significant difference according to addition of molasses. The pH and $NH_4-N$ concentration in liquid fertilizer containing 20% of fish meal was highest after fermentation process, and EC value increased as the content of fish meal increase. When Cucumber was cultivated using liquid fertilizer, there was no difference in growth between fish meal liquid fertilizer treatment and chemical fertilizers treatment. However, there was a difference in yield according to the supply amount of nitrogen during the growing season.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.2
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• pp.92-99
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• 2002

The study was conducted to investigate the changes of soil properties and evaluation of plant utilization according to the application of compost used with phyllite. At this experiment, the plant cultivation test(lettuce and radish plant) was carried out to know about physico-chemical properties of compost, humus degradarion and stabilization degree, and some effects among rhe treatments were best at 20Mg/ha in PSPC 10(Phyllite, Saw dust, Pig manure Compost) plots and ar 10Mg/ha in PSPC 20 treatments, respectively. The EC value was high in the compost. Therefore the EC was appeared more than 2ds/m at the applied 40Mg/ha with compost. And in case of lettuce, Avail.-$P_2O_5$ and EC were more increased than in the radish plots, highly. In contrast, in case of radish, Toral-N, Total-C, and EC contents were decreased after plant cultivation. That is, it could know that radish was fond of absorprion of nitrogen. Also, BD values of soil physical properties were decreased according to increasing of phyllite addition ratio, however water holding capacity(WHC) was increased. The plant test had not been darnaged through the application of compost used with phyllite in soil and there had not been worse on changing of soil physico-chemical properties. Consequently, phyllite composts have been thought on agricultural utilized possibility.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.75-86
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• 1994

Garbage composting was studied in a controlled batch reactor with the addition of cooked rice as a biodegradable carbon source to find the effect of C/N ratio control on composting. And composting of bulking agents such as sawdust and wheat straw were tested with the addition of ammonium sulfate as a nitrogen source. As expected, biodegradation of the garbage having low C/N ratio was improved to some extent when foreign carbon was added. But bulking agents used in this study exerted slightly biodegradable carbon potential, indicating that the estimation of the dose of additional carbon considering desirable C/N ratio was not reasonable when lignocellulosic bulking material was added to garbage. It was found that the optimum moisture content increased with sawdust addition meaning the C/N ratio increment. Considering the above results, it was suggested that 78g sawdust per 100g garbage should be mixed to make C/N ratio to 25 and moisture content to 56% for effective composting of the garbage studied in this paper.

• Resources Recycling
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• v.29 no.5
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• pp.64-72
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• 2020

When the multi-stage combustion process is applied to the cement kiln to reduce nitrogen oxide emissions in the cement industry, oxidation/reduction section that can increase combustion efficiency by reducing NO_x to NO and completely burning unburned materials is essential In this study, when applied the oxidation/reduction system of the cement kiln preheater and calciner, the optimal oxidation/reduction calcination crisis that can secure the quality stability of the final product, cement clinker, was to be observed macroscopically, and the mass change of raw materials according to the burning conditions, decarbonation rate, and calcination rate were investigated. The results showed that the thermal decomposition of raw materials tends to be promoted in the oxidation condition rather than in the reduction condition, and that the thermal decomposition of limestone, which has a relatively high CaO content, is carried out later than that of cement raw meal, which is thought to be caused by the CO₂ fractionation in the kiln. The thermal decomposition properties of raw materials according to oxidation/reducing burning condition showed a relatively large difference in temperature range lower than normal limestone themal decomposition temperature, which is thought to be expected to improve the thermal efficiency of raw materials according to the formation of oxidation condition in the section 750℃ of burning temperature. However, for this study, lab scale. Because there is a difference from the field process as a scale study, it is deemed necessary to verify the actual test results of the pilot scale.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.64-78
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• 2011

Surface of hydrophobic polyethylene membrane was modified to become hydrophilic by ion beam irradiation. Submerged membrane filtration reactors contained pristine membrane or surface-modified membrane and the influent to reactors was pickled radish wastewater. The objectives of this study was to investigate the variation of flux and pressure and the characteristics of pollutant removal such as organics, suspended solids and nutrients with time. The result of experiments using intermittent pristine membrane showed the occurrence of severe fouling by increasing permeate pressure rapidly in case of pickled radish wastewater but in synthetic wastewater, this phenomenon was not occurred. In experiments of variation flux after chemical cleaning and water cleaning in pristine membrane, chemical cleaning must be necessary for renewals of pollutant membrane. Performance of intermittent operation is higher than that of continuous operation. Reaching fouling time in the case of surface-modified membrane is 6 times as long as pristine membrane. According this reason, replacement expense of surface-modified membrane could be 1/6 of that of pristine membrane. Effluent from this process was relatively good water quality and performance in the removal efficiency of SS, nitrogen and phosphorus was particularly higher.