• Journal of the Korean Wood Science and Technology
• /
• v.2 no.3
• /
• pp.3-16
• /
• 1974

One of the disadvantages of. wood and wood products is their hydroscopicity or dimensional instability. This is responsible for the loss of green volume of lumber as seasoning degrade. Dimensional stabilization is needed to substantially reduce seasoning defects and degrades and for increasing the serviceability of wood products. Recently, considerable world-wide attention has been drawn to the so-called Wood-Plastic Composites by irradiation-and heat-catalyst-polymerization methods and many research and developmental works have been reported. Wood-Plastic Composites are the new products having the superior mechanical and physical properties and the combinated characteristics of wood and plastic. The purpose of this experiment was to obtain the basic data for the improvement of wooden materials by manufacturing WPC. The species examined were Mulpurae-Namoo (Fraxinus, rhynchophylla), Sea-Namoo (Carpinus laxiflora), Cheungcheung-Namoo (Cornus controversa), Gorosae-Namoo (Acermono), Karae-Namoo(Juglans mandshurica) and Sanbud-Namoo (Prunus sargentii), used as blocks of type A ($3{\times}3{\times}40cm$) and type B ($5{\times}5{\times}60cm$), and were conditioned to about 10~11% moisture content before impregnation in materials humidity control room. Methyl methacrylate (MMA) as monomer and benzoyl peroxide (BPO) as initiator are used. The monomer containing BPO was impregnated into wood pieces in the vacuum system. After impregnation, the treated samples were polymerized with heat-catalyst methods. The immersed weights of monomer in woods are directly proportionated to the impregnation times. Monomer impregnation properties of Cheungcheung-Namoo, Mulpurae-Namoo and Seo-Namoo are relatively good, but in Karae-Namoo, it is very difficult to impregnate the monomer MMA. Fig. 3 shows the linear relation between polymer retentions in wood and polymerization times; that is, the polymer loadings are increasing with polymerization times. Furthermore species, moisture content, specific gravity and anatomical or conductible structure of wood, bulking solvents and monomers etc have effects on both of impregnation of monomer and polymer retention. Physical properties of treated materials are shown in table 3. Increasing rates of specific gravity are ranged 3 to 24% and volume swelling 3 to 10%. ASE is 20 to 46%, AE 14 to 50% and RWA 18 to 40%. Especially, the ASE in relation to absorption of liquid water increases approximately with increase of polymer content, although the bulking effect of the polymerization of monomer may also be influential. WPCs from Mulpurae-Namoo and Cheungcheung-Namoo have high dimensional stability, while its of Karae-Namoo and Seo-Namoo are-very low. Table 4 shows the mechanical properties of WPCs from 6 species. With its specific gravity and polymer loading increase, all mechanical properties are on the increase. Increasing rate of bending strength is 10 to 40%, compression strength 25 to 70%, ;impact bending absorbed energy 4 to 74% and tensile strength 18 to 56%. Mulpurae-Namoo and Cheungcheung-Namoo with high polymer content have considerable high increasing rate of strengths. But incase of Karae-Namoo with inferior monomer impregnation it is very low. Polymer retention in cell wall is 0.32 to 0.70%. Most of the polymer is accumulated in cell lumen. Effective. of polymer retention is 58.59% for Mulpurae-Namoo, 26.27% for Seo-Namoo, 47.98% for Cheungcheung-Namoo, 25.64% for Korosae-Namoo, 9.96% for Karae-Namoo and 25.84% for Sanbud-Namoo.

• Korean Journal of Soil Science and Fertilizer
• /
• v.32 no.3
• /
• pp.285-294
• /
• 1999

Changes of chemico-physical properties and mturitiy during pig manure composting were analysed using three kinds of bulking agents with rice hull(T1), rice hull and extruding hull mixture (T2, 1:1, v/v), and extruding hull(T3). During composting process, temperature of T1, T2 and T3 were maintained over $50^{\circ}C$ for 31, 21, and 35 days respectively. Organic matter content of each treatment was decreased from 82.2%, 82.0%, and 82.8% to 70.5%, 68.9% and 69.7% and pH increased to 8.85, 9.91, and 8.80, respectively. Total nitrogen content of all treatments gradually decreased, but C/N ratio, phosphorous, and potassium content did not, show any changes during composting process. Both germination rate and early growth were tested using radish seeds for composting maturity. From those results, it was concluded that all treatments were stabilized after 45th day and extruding hull(T3) added compost was superior to others. The test of suppressive effect showed that all treatment have no effect against Fusarium oxysporum, Alternaria altemata, Botrytis cinerea. Compost supplemented with rice hull showed an inhibitory effect after 30th days, while compost supplemented with rice hull and extruding hull(T2) had an inhibitory effect during all period against Rhizoctonia solani. But treatment with extruding hull(T3) added compost did not have any inhibitory effect against Rhizoctonia solani. Only 63th samples in T1 and T2 treatment showed inhibitory effect against Colletoerichum gloeosporioides. However, T3 did not. Suppressive effect of extracts from 67 kinds of composts was investigated in vitro against plant pathogens, such as Fusauum oxysporum. Alternaria alternata, Colletotrichum gloeospoioides, Rhizoctonia solani, and Botrytis cinerea. Thirty two of them showed inhibitory effect against more than one phytopathogen, nine against one pathogen, four against two, six against three, six against four, and seven against five.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.8 no.4
• /
• pp.160-167
• /
• 2000

This study was performed to evaluate efficiency of soil microbial inoculator for active composting of food waste. In addition the number of microorganisms in roil microbial inoculator and the effect of seeding in the process of composting were investigated. food waste samples collected from a refectory were analyzed for physical-chemical properties. The samples were adjusted to moisture content of 65% by saw dust and seeded with soil microbial inoculator of 10% by the weight in case of reactor B. The number of microorganisms, aerobic bacteria, actinomyces, yeast, and fungi in soil microbial inoculator were over $2.98{\times}10^9/g$, $3.93{\times}10^7/g$, $1.21{\times} 10^5/g$, and $5.79{\times}10^7/g$, respectively. During the process of composting, the highest temperatures were $63.4^{\circ}C$ at reactor A(unseeded control)after 10 days and $66.8^{\circ}C$ at reactor B(seeded compost) after 4 days. The pH values of reactor A and B rapidly increased after 3 days and after first few days during composting period, respectively. The highest $CO_2$ concentrations were 6.1%(after 10 days) and 10.8%(afer 4 days) in reactor A and B, respectively. The degradation rates of organic matter(rd) between reactor A and B increased by 17.1% and 64.5%, respectively Consequently, the effects of Inoculation on comporting parameter such as temperature increasing, pH change, chemical properties, and the degradation rates of organic matter(rd) were higher in seeded compost than in unseeded control.

• Korean Journal of Organic Agriculture
• /
• v.15 no.4
• /
• pp.425-435
• /
• 2007

This study was conducted to investigate the effect of different ratios of rice straw to swine manure as an earthworm feed on the change of physico-chemical characteristics and earthworm viability during composting, and further to provide the basic information for an efficient vermicomposting using the manure of livestock. Experimental earthworm used in this study was Eisenia foetida and the ratio of swine manure and rice straw was determined to 100:0(SM), 90:10(SRS 10), 80:20(SRS20), 70:30(SRS30) and 60:40(SRS40) on the basis of volume. The results are summarized as follows. Earthworm appeared after 8 week of aging period, and it was possible for the earthworm to survive in all the treatments. C/N ratio was significantly higher (P<0.05) in the treatments of rice straw mixture (SRS30 and SRS40) than swine manure alone (SM treatment). Appropriate C/N ratio for earthworm survival was the range of 10.43 to 11.16. During the period of aging, pH value and electrolytic conductivity (EC) were the highest in the treatment of swine manure alone. However, as the inclusion of rice straw was increased, pH value and EC showed a decreasing tendency. Appropriate pH value and EC for earthworm survival were 7.7 to 7.8, and 2.72 to 4.59mS/cm, respectively. The results from this study indicated that mixing swine manure with rice straw more improved more physico-chemical environment for earthworm growth in comparison with swine manure alone, and rice straw showed the sufficient possibility as a bulking agent for an efficient vermicomposting of swine manure.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.22 no.3
• /
• pp.11-22
• /
• 2014

The buffer capacity of food waste lowers during the collecting and transportation period. Food waste usually shows deficiency of micro nutrients especially molybdenum(Mo) and cobalt(Co). Therefore, food waste can be considered as a good mixture of livestock waste to enhance methane production. The objective of this study was to investigate the correlation between properties of substrates (local food waste and livestock manure) and methane yields for successive anaerobic fermentation process and its stable management. Food wastes were taken at an intermediate storage or treatment system provided by eight local authorities (Gangnam, Gangdong, Gwanak, Guro, Dongjak, Songpa, Yeongdeungpo, and Younsan) in Seoul. The solid content and potential methane yield of food wastes were average of 16% and $446.6STP-m{\ell}/g-VS$ (range from 334.8 to $567.5STP-m{\ell}/g-VS$) respectively. As for the beef cattle manure, the solid content and potential methane yield had an average of 26% and $280.6STP-m{\ell}/g-VS$ respectively. Potential methane yield had a positive correlation with fat content, and hydrogen content and a negative correlation with carbohydrate content ($r^2&gt;0.8$). Therefore, the potential methane yield can be predicted based on the substrate characterization results with reasonable accuracy. Further research may be needed to investigate the relation of the properties of the mixture substrate and methane production rate. The mixtures may include food waste, livestock waste, and bulking agents (saw dust, rice hull, or agricultural byproducts etc.) to determine best combination of these substrates for maximum methane production rate.

• Journal of agriculture & life science
• /
• v.51 no.4
• /
• pp.139-147
• /
• 2017

This study was carried out in order to reduce the amount of sawdust for recycling the generated manure from livestock farms, and to investigate the effects on the reducing usage of sawdust and quality of produced compost. To do this, a cylindrical horizontal composting device were used in the experiments and compost was analyzed for judging produce compost quality. The experiment was carried out separately under different cases of operational control conditions. The first case was produced by using sawdust and pig manure mixture(Test-1); the second case was produced by using sawdust, pig manure and the previously produced compost(Test-2). In the second case, Except for some heavy metal content, The water content and C/N ratio were found to be suitable for fertilizer process specification of the RDA(Rural Development Administration) and it was found to reduce the sawdust 1.25tons usage.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.9 no.1
• /
• pp.56-64
• /
• 2001

Composting of livestock feces is economic and safe process to decrease the possibility of direct leakage of organic pollutants to ecosystem from commercial and environmental point of view. This study was conducted with three different experiments related to composting of livestock feces. The purpose of experiment 1 was to investigate changes of characteristic of compost pile during composting period by low temperature in cold season. To compare composting effect of experimental compost pile and control pile exposed in cold air, experimental compost piles were warmed up by hot air until their temperatures were reached at $35^{\circ}C$. Sawdust, Ricehull and Ricestraw were mixed with livestock feces as bulking agent. The highest temperatures of compost pile during composting period were in sawdust, rice hull, rice straw, and control were $75^{\circ}C$, $76^{\circ}C$, $68^{\circ}C$, $45^{\circ}C$ respectively. Moisture content, pH, C/N and volume of compost were decreased during composting period. Experiment 2 was carried out to study utilization effect of compost by plant. A corn was cultivated for 3 years on fertilized land with compost and chemical fertilizer. The amount of harvest and nutrition value of corn were analyzed. In first year of trial, the amount of harvest of corn on land treated with compost was lower by 20% than that of land treated with chemical fertilizer. In second year, there was no difference in yield of com between compost and chemical fertilizer. In third year, the yield of com on land fertilized with compost was much more than that of land fertilized with chemical fertilizer. The purpose of experiment 3 was to estimate the decrease of malodorous gas originating from livestock feces by bio-filter. Four types of bio-filters filled with saw dust, night soil, fermented compost and leaf mold were manufactured and tested. Each bio-filter achieved 87-95% $NH_3$ removal efficiency. This performance was maintained for 10 days. The highest $NH_3$ removal efficiency was achieved by leaf mold on the first day of operation period. It reduced the concentration of $NH_3$ by about 95%. Night soil and fermented compost showed nearly equal performance of 93 to 94% for 10 days from the beginning of operation. The concentration of hydrogen sulfide and methyl mercaptan originating for compost were equal to or less than $3mg/{\ell}$ and $2mg/{\ell}$, respectively. After passing throughout the bio-filter, hydrogen sulfide and methyl mercaptan were not detected.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.25 no.2
• /
• pp.59-67
• /
• 2017

The aim of this experiment was to investigate the effect of air suction rate (SR) during the composting process of swine manure mixed with sawdust used as a bulking agent. In the 25 L composting reactors, the suction rate (SR) was at four different treatment levels (100%, 200%, 300%, 400%), and were fixed on the based on constant aeration rate into the composting mixtures. The temperature reached to thermophilic phase within 2 days and it was maintained up to the $5^{th}$ day of the composting process in all reactors and then gradually decreased to room temperature at the end of the composting process. The moisture content (MC, %) of the initial mixtures was 64.27%, and it was reduced to 38.4, 33.08, 14.59 and 11.93 in the different suction rate of 100%, 200%, 300%, 400%, respectively in the end process. During the composting, the level of pH was increased from 6.83 to 8.67 and it gradually decreased to 7.56 in 100% and 200%(SR). At the same time, the pH values were reduced only up to 8.19 at 300%, and 8.08 at 400%(SR), showing that suction strengths of 100% and 200% were the better option for composting than those of 300% and 400%. The total Kjeldahl nitrogen (TKN) of initial composts mixtures was 2.3% and were changed in 3.3, 3.1, 2.5, and 2.3% at the end of the composting period from the 100%-400% (SR) variations respectively. These results also indicated that 100% and 200% (SR) were more affected by the dry mass loss as $CO_2$ and water evaporation. The initial value of C/N ratio was 25.17 and were significantly reduced to 11.88, 11.97, 14.31, and 14.72 at the end of the experiment, respectively from the 100%-400% (SR) variations. These results suggest that the suction rate (SR) of 100% and 200% relative to constant air supply would be the optimal conditions to produce high-quality compost.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.63 no.2
• /
• pp.164-173
• /
• 2018

Elevated atmospheric carbon dioxide concentration ($CO_2$) is a major component of climate change, and this increase can be expected to continue into the crop and food security in the future. In this study, Soil-Plant-Atmosphere-Research (SPAR) chambers were used to examine the effect of elevated $CO_2$, temperature, and drought on the canopy architecture and concentration of macronutrients in potatoes (Solanum tuberosum L.). Drought stress treatments were imposed on potato plants 40 days after emergence. Under AT+2.8C700 (30-year average temperature + $2.8^{\circ}C$ at $700{\mu}mol\;mol^{-1}$ of $CO_2$), at maximum leaf area, elevated $CO_2$, and no drought stress, a significant increase was observed in both the aboveground biomass and tuber, and for the developmental stage. Even though $CO_2$ and temperature had increased, AT+2.8C700DS (30-year average temperature + $2.8^{\circ}C$ at $700{\mu}mol\;mol^{-1}$ of $CO_2$ under drought stress) under drought stress showed that the leaf area index (LAI) and dry weight were reduced by drought stress. At maturity, potatoes grown under $CO_2$ enrichment and no drought stress exhibited significantly lower concentrations of N and P in their leaves, and of N, P, and K in tubers under AT+2.8C700. In contrast, elevated $CO_2$ and drought stress tended to increase the tuber Mg concentration under AT+2.8C700DS. Plants grown in AT+2.8C700 had lower protein contents than plants grown under ATC450 (30-year average temperature at $400{\mu}mol\;mol^{-1}$ of $CO_2$). However, plants grown under AT+2.8C700 showed higher tuber bulking than those grown under AT+2.8C700DS. These findings suggest that the increase in $CO_2$ concentrations and drought events in the future are likely to decrease the macronutrients and protein concentrations in potatoes, which are important for the human diet.

• Journal of Animal Environmental Science
• /
• v.13 no.1
• /
• pp.13-20
• /
• 2007

Sawdust biofiltration is an emerging bio-technology for control of ammonia emissions including compost odors from composting of biological wastes. Although sawdust is widely used as a medium for bulking agent in composting system and for microbial attachment in biofiltration systems, the performance of agitated bed composting and sawdust biofiltration are not well established. A pilot-scale composting of hog manure amended with sawdust and sawdust biofiltration systems for practical operation were investigated using aerated and agitated rectangular reactor with compost turner and sawdust biofilter operated under controlled conditions, each with a working capacity of approximately $40m^3\;and\;4.5m^3$ respectively. These were used to investigate the effect of compost temperature, seed germination rate and the C/N ratio of the compost on ammonia emissions, compost maturity and sawdust biofiltration performance. Temperature profiles showed that the material in three runs had been reached to temperature of 55 to $65^{\circ}C$ and above. The ammonia concentration in the exhaust gas of the sawdust biofilter media was below the maximum average value as 45 ppm. Seed germination rate levels of final compost was maintained from 70 to 93% and EC values of the finished compost varied between 2.8 and 4.8 ds/m, providing adequate conditions for plant growth.