• Resources Recycling
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• v.2 no.4
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• pp.10-16
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• 1993

Reduction behavior of stainless steelmaking dust by microwave heating process was investigated using coke and charcoal as reducing agents. Pellet dust and stanless steelmaking dust pelletized with reducing agent were reduced by the heating upto $1000^{\circ}C$ in microwave oven. The results showed that charcoal and coke seemed effective in the reduction of metals from stainless steelmaking dust by microwave heating and charocal was found to be better than coke. Degree of reduction seemed similar with the power of 500W and 700W in microwave oven. Dusts were rapidly reduced within 20 minutes. Reducing degree decreased in the order of Fe>Ni>Cr.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.405-410
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• 1999

This study was performed to find the recycling performance and to provide design data during recycle solid composting system to reduce bulking agent cost, Dairy manure amended with rice hulls and recycled compost was composted in a laboratory -scale vessel by continuous aeration for 10 days. The temperature and ammonia emission variations according to the ratios of bulking agents during the primary aeration stage were surveyed. Also, the influence of fresh compost quality on the recycling performance were anlayzed. While recycled composting system were operatured. The temperature in compost was maintained in the range of 40∼60$^{\circ}C$ needed for biodegradation and death of pathogenic organisms, but the ammonia emission was different by the ratios of recycled compost. The ammonia emission increased due to the low C/N ratio(17.6), high pH value(8.1) of the recycled compost.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.19-29
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• 1994

The purpose of this study was to investigate the feasibility of composting of vegetable wastes containing high moisture. The parameters investigated were the effect of energy source addition, difference in bulking agent and recirculation of leachate produced during composting. Laboratory scale composting reactors were used in this study. Chinese cabbages were used as a vegetable waste. Dog food was added to the vegetable waste as a energy source. Wood chips and leaves of platan were used as bulking agents. There may be an appropriate amount of energy source to be added for composting high moisture content vegetable waste. In this study, the appropriate amount of energy source was 20% of the vegetable waste by weight basis. Recirculation of total amount of leachate produced each day on the same day may not be an appropriate approach due to the significant heat-quenching effect. When the total amount of leachate produced was equally devided and recirculated everyday through the whole composting period, the heat-quenching effect was comparatively less significant. There were no notable differences in the temperature profile and the $CO_2$ evoluation rate when leaves were used instead of wood chips as bulking agents. Considering waste recycling, it is desirable to use leaf waste as bulking agents if available, because the leaves are also wastes to be disposed of.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.4 s.117
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• pp.31-40
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• 2006

Presence of old newspapers printed with waterbased flexographic inks leads to a significant loss of brightness of the deinked pulp by flotation process. It has been shown that neutral or acidic flotation deinking has many advantages in recycling of flexo printed newsprints. A comparative experimental study was performed to evaluate the deinking efficiency of three alcohol type deinking agents in flotation deinking of flexo printed newspapers. Zeta potential of neutral deinked pulp was less negative than alkaline deinked pulp. Also neutral deinking was advantages in reducing turbidity, COD, and cationic de-mands of deinking process water.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_3
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• pp.139-148
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• 2001

Heavy metals such as Cu, Ni, Cd, and Pb were chemically extract from the contaminated soils using the chelating agents, EDTA and DTPA. These chemical extraction have been focused on its applicability to a wide range of soils. Results of extractive efficiency for heavy metal follow the order : Cu-EDTA $\geq$ Ni-EDTA > Pb-EDTA > Cd-EDTA > Cu-DTPA> Pb-DTPA. This result is coincided with order of conditional formation constants(Kr) of metal-chelate agent. The second study involved the recovery of the metals and EDTA from complex solutions by an electromembrane process. The overall processes of regeneration, recovery, and reuse were evaluated. The electrochemical studies showed that copper could be chosen as an electrode to plate Cd, Cu, and Pb. At least 95% of 75 of EDTA and associated Cu or Pb could be recovered by the electromembrane process. Recovery of Cd by electodeposition was not possible with the copper electrode. The percent EDTA recovery is equal to the percentage of metal electroplated from the chelates.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.51-64
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• 1994

To compost the food garbage with the dry bean curd and sawdust as the bulking agents, the method of high-speed fermentation by the characteristic microorganisms group was applied. The results of experiments are summarized as follows ; 1. Korean food garbage, which is high in water content, is difficult to compost only by microorganism fermentation without the addition of bulking agents such as dry bean curd cake and sawdust. 2. Weight reduction rates are ranging from 35.6% to 64.5% and varying with the composition of food garbage. The less weight reduction rate is, the longer continuous-fermentation is. And the color of compost is changing sequentially as yellow -> brown -> black. 3. Comparing with the controlled microorganism group, the weight reduction rate and $H_2CO_3$ production rate in the characteristic microorganism group fermentation reactors are higher. And the fermentation rate is satisfactory when the characteristic microorganism group is added. 4. The value of fermented composting as fertilizer diminishes, and the contents of Total Nitrogen, $P_2O_5$, $K_2O$ increase on the condition that the fermentation continues. However, the organic contents and C/N ratio diminish as the fermentation continues. 5. The high-speed fermentation technology demonstractes the possibility of recycling as well as the reduction of composting time provided that it is applied as a pretreatment process for composting.

• Journal of fish pathology
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• v.33 no.1
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• pp.97-101
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• 2020

Although aquaculture production rates grown over the years, aquatic animal diseases occur every year which causes substantial economic losses. When an aquatic animal is infected with an aquatic animal pathogen it is either incinerated or buried according to the aquatic life disease control act. Although these methods prevent the spread of disease, it is not environment friendly. Here, we developed an aquatic animal rendering equipment for disposal of fish waste which is environment-friendly and efficient. Also, fertilizer components of fish waste were evaluated value for recycling. The mobile rendering equipment was designed for field operation and/or high temperature and pressure system, oil and water separator, and shredding drying apparatus. During the experiment (July-2016 to November-2016), a total of 53,824 kg fish waste was collected, and 29,216 kg compost of rendering by-product was made. Also, compost made from viral (Viral hemorrhagic septicemia virus) infected fish did not reflect any detectable pathogen. The concentration of nitrogen, phosphorus, and organic matter in the fish waste compost were 2.17%, 26.98%, and 92.44%, respectively. The results suggest that fish waste used in this study was decomposed efficiently as per the official standard for fertilizer product. This equipment can be useful for efficient inactivation of the aquatic animal pathogenic agents and recycling of the fish waste in an environment-friendly manner.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.141-150
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• 2006

To develop the microbial agents for the environmentally-friendly treatment and recycling of food waste, useful microorganisms, which showed higher degradation activities to various organic compounds and possessed flocculating activities, were isolated from the earthworm. One of the isolated strains, named JS-01, was further selected due to its higher flocculating activity against 0.5% Kaolin clay. JS-01 was identified as Bacillus pumilus sp. by 16s rDNA analysis. The optimal temperature and pH for the growth of JS-01 to express the flocculating activity was found to be at $37^{\circ}C$ in pH 7.0 of EPS broth medium. JS-01 also expressed good degrading activity against cellulose, which is one of the representative organic materials in food waste. We propose that JS-01 will be a good candidate for the efficient treatment of food waste and leachate due to the property to degrade cellulose and flocculating activity.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.15-21
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• 2016

This experiment was conducted to test desorption and recycling characteristics for silver ion adsorbed into waste coffee grounds by using various desorbing agents such as nitric acid, ethylene diamine triacetic acid (EDTA) and nitrilo triacetic acid (NTA). It is appeared that the highest desorption efficiency for silver ions was obtained as about 97.8 % by 1.0 M of nitric acid solution. Also, in the case of less than 1.0 of the ratio of solid and liquid (S/L) (g/L), silver ions adsorbed onto coffee grounds was desorbed as about 98~100 %, and most of desorption process was completed within 60min. In addition, adsorption capacity of reused waste coffee grounds for silver ions was highly maintained as about 43.9 mg/g until the $2^{nd}$ cycle, as compared with the adsorption capacity with 45.9 mg/g of the adsorption capacity for virgin waste coffee grounds.

• Resources Recycling
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• v.27 no.5
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• pp.49-53
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• 2018

In developing an optimum steelmaking process, the purity of the product, environmental impact, capability and cost of the process should be considered. Desulfurization of molten iron is conducted during preliminary treatment stage before converter operation. Although fluorite is added as a desulfurizing agent in CaO and $CaCO_3$ based agents, the concentration of fluorine in slag is strictly regulated. In order to develop desulfurizing agent without fluorine, CaO was mixed with Al dross and ladle slag containing alumina. The characteristics and desulfurizing capacity of the CaO based desulfurizing agent thus prepared were tested by varying temperature of Kanvara Reactor. Our results showed that the desulfurizing capacity of the samples prepared in this work was found to be similar to that of the traditional desulfurizing agents with fluorine.