• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.361-365
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• 1999

This study examined the effects of multiple recycling on deinkability and properties of recycled paper from laser computer printout (LCPO). First, alkaline paper with a 20% printed area was disintegrated by TAPPI standard disintegrator at room temperature. After dewatering, the pulp was flotated and dried in oven at80$^{\circ}C$ for 24 hrs. A sequence of wetting, disintegrating, flotating and drying was one recycling cycle and this cyclic treatment was repeated from zero to five times. The recycled handsheet dropped to 90% of the original brightness after five cycles, and lost the most brightness after five cycles, and lost the most brightness in the first two cycles. However, it had a gain of 10% in opacity after five cycles as the same as the case of nonprinting. And, in this study, the method for determining residual ink(toner) content in recycled handsheets ere established by means of SEM-EDX and Py-GC. The change of residual ink percentage on recycled paper showed the effect of recycling numbers on deinkability of waste paper. A slight decrease in deinkability was noted for the recycled handsheets, which may be due to the change of fiber surface free energy connected with fiber swelling.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.75-85
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• 2012

This study was investigated to develop an alternative medium for the cultivation of oyster mushrooms. The cultivation characteristics for major cultivated varieties of oyster mushrooms were campared with the food waste medium. In addition, water control & a gap formation of food waste is being pointed out as a problem of the medium material. Therefore, certain amounts of earthworm casting were supplied to the food waste medium to overcome the water and compaction phenomenon. This study investigated the use of the total 6 cultivars of oyster mushrooms, the Suhan(PL.1), Chiak No. 5(PL.2), Chiak No. 7(PL.3), Samgu No. 5(PL.4), Samgu No. 8(PL.5), Jangan No. 5(PL.6). In terms of medium, the optimum growth of the mycelium of the oyster mushroom was observed in the beet pulp medium but in food waste, the mycelium's growth was observed as insufficient in the bulk of cultivars. The Jangan No. 5(PL.6) was superior to other cultivars relative to the mycelium's growth. The optimum concentration of earthworm casting added the foodwaste medium was 30%. When Jangan No. 5(PL.6) was incubated in the foodwaste meidum containing 30% earthworm casting, the early days to germination were long, almost double the amount of time than that of the beet pulp medium. However, it was found that the fruit body size was larger than that of the beet pulp by up to 20.5%, and the length of the fruit body was up to 6.2% longer than that of the beet plup. The total yields increased by 60.5%. The analysis results of the oyster mushroom's nutritional contents cultured using the food waste medium, shows that the protein, vitamin A and vitamin E increased 70.6%, 2.4%, 0.8% respectively, the fat decreased by 12.6% and the oleic acid increased in a very small amount compared to that of the beet pulp medium.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.1
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• pp.1-7
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• 2001

The immediate purposes of this study is to establish the surface chemical principles associated with the flotation process of waste papers and to verify them by practical flotation experiments. To achieve this AKD sized hydrophobic microcrystallince cellulose (MCC) with different levels of hydrophobicity, and hydrophilic MCC dyed with black were prepared as model substances. The effects of surface characteristics on flotation efficiency were evaluated by measuing the brightness of the flotation rejects obtained after the flotation experiments carried out using MCC mixtures prepared with different ratios of hydrophobic and hydrophilic MCCs. Results showed that more than 90% of the flotation rejects consisted of hydrophobic MCC indicating the critical importance of the hydrophobicity of the materials in the flotation process. The proportions of hydrophobic materials in the reject remained constant when highly sized MCC was used as a model of hydrophobic substance.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.13-19
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• 2010

Four waste paper mills in Korea, where multifractors, devices for fiber fractionation, were installed, were selected to investigate how effectively and how differently the multifractors were used. They all used slot-type screens. Effective fiber fractionations by fiber length were expected by the multifractors, but in reality, they were used for selecting fiber furnishes that were flexible and hydrated. Flakes, which meant large fiber bundles, were rejected effectively by the multifractors. There existed a high regression coefficient between the fiber length differences and the freeness differences of the accepted and the rejected fiber furnishes.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.1
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• pp.48-53
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• 2003

The objective of this study was to find in what color Korean handmade paper(Hanji) is dyed when it is dyed with a pigment extracted from waste onion peelings using different kinds of mordant, and how the paper is discolored and variety of strength under the condition of accelerated aging test. The results of this experiment are as follows. 1. Korean handmade paper was dyed in different colors according to the kinds of mordant. Mainly it was dyed in orange-brown, and sometimes in gold or khaki. 2. Korean handmade paper dyed was not discolored much, which suggests that the pigment is strong under the condition of aging. 3. As for durability, Korean handmade paper dyed in gold was strongest. Korean handmade paper, to which aluminum sulfate, iron sulfate or sodium dichromate was applied as mordant, had poor durability. Thus, these were not suitable as mordant.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.66-73
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• 2003

Alkaline cellulolytic enzymes are prepared from Coprinus cinereus 2249. Recovery method of enzyme protein from cultured medium and effect factors on enzyme activity of protein were investigated. The results could summarized as follows, \circled1 Amount of enzyme protein from cultured medium was highest in incubation with shaking and addition of skim milk. \circled2 Protein from cultured medium was alkaline enzymatic protein which shows the highest activity at pH 9.0. \circled3 The most effective recovery method of enzyme protein was the precipitation of protein by addition of cultured medium of protein in ethanol. \circled4 The enzyme activity was enhanced by tween-80 and decreased with $Al_2(SO_4)_3$, $H_2O_2$et al, and was little changed with metal ions except $Hg^{++}$.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.1
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• pp.43-51
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• 1997

The various culture conditions of Trichoderma viride(ATCC 3454) and Phanerochaete chrysosporium(ATCC 26921) with glucose-pepton medium, Mandels medium, YMG medium for wood degradable enzyme were examined. Mycellium of the two species grew profusely on glucose-pepton medium. Maximum fungal growth was observed about 10days. But CMCase, Fpase, laccase activity in the culture medium with glucose-pepton was not detected. When grown in fermenter culture using Mandels medium, Trichoderma viride produced CMCase and Fpase. Its CMCase activity was 0.15 lU/ml and Fpase activity was 0.3 IU/ml within about 4-6days. Phanerochaete chrysosporium grown in a YMG medium gave the best enzyme activity when they were grown under stationary culture with an atmosphere of 100% oxygen. Levels of laccase activity of 3.0 mull were achieved in stationary culture under 100% oxygen. The enzyme condensation by ultrafiltration method caused a 2-fold(cellulase) and 6-fold(laccase) as compared to control activity.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.79-83
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• 1999

A cationic demand(CD) is a very useful indication for determining the optimum dosage rate of retention aids to the papermaking stock at the wet end. Polyelectrolyte titration has been most often used to determine a CD. Highly accurate results can be obtained by this method when the ionic strength of sample is low. But this is accompanied by the serious errors when the ionic strength is higher than that corresponding to 20 milli molar(mM) monovalent, 2 mM divalent or 0.2 mM trivalent ions because of no occurrence of the end point of titration. Therefore, it is very difficult or almost impossible for the conventional method to be applied to the industrial suspensions such as papermaking stock and industrial waste water. Then a novel method using chromophoric labeled cationic polymer which can be applicable to the sample with high ionic strength has been developed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.44-51
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• 2001

Sedimentation characteristics such as SS, $BOD_5$, COD removal efficiency of waste water in the toilet paper mill using milk carton were examined. Optimum dosage of coagulant, rapid mixing time and slow mixing time were determined by turbidity, SS, COD, $BOD_5$ and then equation for treatment efficiency was suggested. Mechanical strength of floc was determined by turbidity. For the coagulant, polyacrylamide (PAM) is more efficient for removing pollution than the aluminium sulfate. Effective mixing ratios of PAM and aluminum sulfate to remove pollution are 70:30 and 30:70. The lowest turbidity was showed when rapid mixing at 300 rpm after coagulant injection was applied. That which indicates the highest point of flocs mechanical strength.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.3
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• pp.69-81
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• 1997

Up to now 5 Voith Sulzer paper machines with multi-layer headbox and Gapfor-mer are sucessfully running on papckaging papers. Linerboard, testliner and corugating medium is produced in the basis weight range from 105 to 275 $g/m^2$ at machine speeds up to 900 m/min. The nest one, starting up in Oct. ｀96 in Germany, will be the world＇s fastest paper machine for packaging papers. The 5.6 m wide machine is designed for a maximum operating speed of 1200 m/min. Approx. 220.000 tons of corrugating medium and testliner based on 100% waste paper in the basis weight range from 90 to 160 $g/m^2$ will be produced each year. An expansion stage planned for the future is intended to increase annual output to 280.000 tons. This machine will not only be the fastest one for packaging papers, it also comprises all described innovative key components which are available today in order to fulfill growing demands of the future with regard to quality and productivity. The concept of this advanced machine is shown in Fig. 9.