• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.4
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• pp.95-104
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• 2004

A styrene solution of waste expanded polystyrene with a crosslinking agent and an initiator was used as a binder for waste wood-plastic composite panels. The waste wood-plastic composite panels are prepared with various binder contents and filler-binder ratios by using a hot press molding method. The apparent density of the composite panels is increased with increasing binder content and filler-binder ratio, while their water absorption and expansion in thickness are decreased with increasing binder content and filler-binder ratio. The maximum flexural strength and wet flexural strength of the composite panels are obtained at a binder content of 35% and a filler-binder ratio of 0.8. Decreases in the flexural strengths of the composite panels due to water immersion at 20 and $100^{\circ}C$ are hardly recognized at binder contents of 30% or more.

• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.21-29
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• 2005

One way to recycle the construction wastes is to use the waste concrete aggregates as the pavement materials. Although there are many studies and technical developments about waste concrete aggregates, the impurities produced in the process of the aggregate production prevent the use of the waste concrete aggregates in the pavement construction. In this study, the impurities included in the recycled waste aggregates were classified into inorganic and organic ones according to their characteristics, and the influences of each impurities on the pavement performance were presented. It was also showed that the limit of impurity content in the lean concrete base through the correlation between the inorganic impurity content and the compressive strength, and that in the granuler subbase layer through the correlation between the organic impurity content and the modified CBR. In conclusion, it is possible to apply waste concrete aggregates for the pavement when inorganic impurity content is less than 10% in the lean concrete base, and organic impurity content is less than 2% in granular subbase.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.27-33
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• 2012

According to the statistics of the Ministry of Environment, the emission of sewage sludge is increased by 7~9% yearly. In the future, it will be increased continuously because of extension of sewage disposal plants, high class treatment for removing nitrogen and phosphorus. Until now, we have depended on reclamation for lots of quantity and some part has been treated by ocean emission. But, direct reclamation of organic waste will be prohibited and even ocean emission will be prohibited now, so the treatment of sludge is put on emergency alert. Bio-gas can be produced by applying anaerobic digestion method for the recycling or refuse derived fuel can be conducted by applying carbonization method. However, the process is difficult, causes bad smell and makes it the second waste, so it cannot be practical method in fact. This study applied a fluidized bed combustor for sewage sludge treatment technologies that can actually take advantage of key technologies in order to verify its purpose is to demonstrate selected. If applying the fluidized bed combustor, it can be easily utilized as the replaced resource of energy(fuel) in the countries whose energy resources are insufficient, like our country. Especially, if applying only original strengths of the fluidized bed combustor sufficiently, the sewage sludge can be treated simply, eco-friendly, sanitarily and economically. Particularly, it is verified as the energy technology suitable for government's green growth policy.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.55-70
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• 2009

The long-term effects and the soil environmental changes were examined to ensure the safety of food waste compost in agricultural use. Based on conventional nitrogen application rate of chemical fertilizer, Pig manure compost with $24g\;N\;kg^{-1}$, $8g\;P_2O_5\;kg^{-1}$, and $10.4g\;K_2O\;kg^{-1}$ and food waste compost with $20g\;N\;kg^{-1}$, $20.1g\;P_2O_5\;kg^{-1}$, and $6.5g\;K_2O\;kg^{-1}$ were applied to the paddy soil in $2{\times}2{\times}2m$ lysimeter in which paddy rice (Oryza sativa L. var Chucheong) were grown. The rice grown where food waste compost applied showed better growth responses than control, whereas less yield rate than chemical fertilizer applied. The contents of organic matter, nitrogen, and phosphorus after experiment were increased with compost applied. In addition, it improved soil aeration by the application of food waste compost, while little difference was observed in the quality of surface, infiltrated, and ground water compared to chemical fertilizer applied or control.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.4
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• pp.296-306
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• 2014

This study was conducted to survey and analyze the quantity of various organic wastes and to vitalize the utilization of agri-food by-products as raw materials for Total mixed ration (TMR), to improve feed cost savings and the quality of animal products. On-the-spot obstacles for animal farmers, along with legal and institutional alternatives are presented. The results are as follows. First, organic wastes in Korea are managed by the Allbaro system created in the Wastes Control Act, which processes 10,488 tons of cooking oil waste, 832,493 tons of animal and plant residues, 5,740 tons of animal carcasses, 1,171,892 tons of animal residues, and 2,172,415 tons of plant residues including 12,905 tons of rice hull and bran, for a total of 4,205,931 tons. Raw materials for TMR, namely rice hulls and bran as well as plant residues, accounted for 51.7% of the total national organic waste. The top 10 municipalities process 76~100% of all organic wastes and a supply management system is needed for the waste. Second, the 10 major agri-food by-products used as raw materials for TMR are bean curd by-product, rice bran, oil-cake, brewers dried grain, Distiller's Dried Grains with Solubles (DDGS), barley bran, soy sauce by-product, citrus fruit by-product, mushroom by-product and other food by-product (bread, noodles, snacks, etc.). Third, the biggest difficulties in using agri-food by-products are legal obstacles. Because agri-food by-products are regulated as industrial wastes by the Waste Control Act, animal farmers that wish to use them have legal reporting obligations including the installation of recycling facilities. To enable the use of agri-food by-products as raw materials for TMR, waste management system improvements such as 'the end of waste status' and the establishment of more than 10 public distribution centers nationwide are deemed essential.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.39-45
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• 1998

As a basic research for developing a sludge application technique in forestry, this study was conducted to investigage a reasonable amount and period of sludge to be applied onto forest nursery of Acer palmatum Thunb. The paper mill sludge was used for the study, and ammonium nitrate was treated to some of them to reduce the C/N ratio lower than 40. The maximum amount of applied sludge was 7ton/ha/year, and they were spread on spring and on late summer. The sludge application did not stimulate early growth of the trees during a year. Since there was no significant changes in soil chemical properties, the amount of applied sludge was thought to be too little to result in a significant role for tree growth. However, the soil water showed significant increase of Cu when the activated sludges were applied during late summer. Thus, the time of application need to be determined cautiously with considering the risk of ground water contamination. In conclusion, if we set a goal from the view point of long-term concept such as forest productivity rather than to get a short-term product, the uncomposted sludge in small amount during growing season might be considered to be applied on forest nursery.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.2
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• pp.44-49
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• 2014

In order to remove the heavy metals from synthetic wastewater containing Pb, Cr, and Cd, the experiment was conducted with a variety of concentration and pH by using the washed and dried coffee grounds as adsorbent. Almost of the heavy metals were removed in thirty minutes and the removal efficiency was maximized to the 80 percents following the different pH conditions. Furthermore, in the case of Cr, the removal efficiency was declined with the increasing of pH. As a result of this study, coffee grounds is proved to be a very good adsorbent to remove the heavy metals.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.27-39
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• 2009

The main objective of this study is to investigate the characteristics of combustion by analyzing fuel gases from a combustion equipment with various combustion conditions for refuse-derived fuels (RDFs). CO gas is a parameter for indicating of incomplete combustion during a combustion process. The lowest CO gas was produced when the experiment conditions were m=2 under air-fuel condition and $800^{\circ}C$. $CO_2$ gas is a final product after complete combustions. The highest amount of $CO_2$ gas was produced when the experiment conditions were m=2 under air-fuel condition and $800^{\circ}C$. The highest level of $SO_2$ gas was produced in S.1 sample containing the highest sulfur. The highest level of NOx gas was produced in S.1 sample with the highest nitrogen content and air-fuel condition of m=2 under temperature of $800^{\circ}C$. HCl gas that is generated by reacting with metals catalyst through oxygen catalyst reaction during combustion process is a precursor of dioxin formation. The higher level of HCl gas was produced in the sample with higher chlorine content. The lowest level of HCl gas was produced when the experiment conditions were air-fuel condition of m=2 and $800^{\circ}C$. The lowest level of $NH_3$ gas was generated when the experiment condition was m=2 under air-fuel condition and after 3 minutes. Air-fuel condition is more important to create $NH_3$ gas than operating temperatures. Higher level of $H_2S$ gas was generated in S.1 sample with the higher sulfur content and was created in RDFs that contain higher mixture ratios of sewage sludge and food wastes. A result of combustion, gases and gases levels from the combustion of S.1 and S.2 were very similar to the combustion of a stone coal. As results of this research, when evaluating the feasibility of the RDFs, the RDFs could be used as auxiliary and main fuels.

• Journal of Environmental Science International
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• v.24 no.2
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• pp.237-244
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• 2015

This objectives of research are to figure out combustion characteristics with increasing temperature with petrochemical sludge by adding wasted organic matters which are waste electric wire, anthracite coal and sawdust, and to exam heating value and ignition temperature for using refused derived fuels(RDFs). After analyzing TGA/DTG, petrochemical sludge shows a rapid weight reduction by vaporing of inner moisture after $170^{\circ}C$. Gross weight reduction rate, ignition temperature and combustion rates represent 68.6%, $221.9^{\circ}C$ and 54.1%, respectively. In order to assess the validity of the RDFs, the petrochemical sludge by adding wasted organic matters which are waste electric wire, anthracite coal and waste sawdust. The materials are mixed with 7:3(petrochemical sludge : organic matters)(wt%), and it analyzes after below 10% of moisture content. The ignition temperatures and combustion rates of the waste electric wire, anthracite coal and waste sawdust are $410.6^{\circ}C$, $596.1^{\circ}C$ and $284.1^{\circ}C$, and 85.6%, 30.7% and 88.8% respectively. In heating values, petrochemical sludge is 3,600 kcal/kg. And the heating values of mixed sludge (adding 30% of the waste electric wire, anthracite coal and waste sawdust) each increase up to 4,600 kcal/kg, 4,100 kcal/kg and 4,300 kcal/kg. It improves the ignition temperatures and combustion rates by mixing petrochemical sludge and organic matters. It is considered that the production of RDFs is sufficiently possible by using of petrochemical sludge by mixing wasted organic matters.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.71-81
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• 2009

Food waste has been actively used as a composting material in order to reduce the environmental pollution load and to enhance the recycling of resources. In this study, the longterm effects of continuous application of food waste compost to soils on both the crop production and the soil properties were examined to ensure the safety of food waste compost in agricultural use. In addition, we collected the preliminary data for establishing standard application rate of food waste compost for agricultural utilization. Based on conventional nitrogen application rate of chemical fertilizer for crop cultivation, pig manure compost $(24g\;N\;kg^{-1}$, $8g\;P_2O_5\;kg^{-1}$, and $10.4g\;K_2O\;kg^{-1})$ and food waste compost ($20g\;N\;kg^{-1}$, $20.1g\;P_2O_5\;kg^{-1}$, and $6.5g\;K_2O\;kg^{-1}$) were applied to the upland soil in $2{\times}2{\times}2m$ lysimeter in which lettuce (Lactuca sativa var. crispa), Chinese cabbage (Brassica campestris subsp. napus var. pekinensis), red pepper (Capsicum annuum), and potato (Solanum tuberosum) were grown continuously. The crops grown in soils to which food waste compost applied showed better growth responses than the control, whereas some variations were observed in the crops grown in chemical fertilizer treated soils. Continuous application of food waste compost increased the contents of organic matter, nitrogen, and phosphorus, which resulted in improving soil aeration.