• Membrane Journal
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• v.12 no.1
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• pp.8-20
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• 2002

In this study using $N_2$-back flushing, which wwas not the general back-flushing method of membranes, the discharged wastewater from a paper plant was filtrated by 4 kinds of tubular carbon ceramic ultrafiltration membranes. We could in vestigate effects of $N_2$-back flushing period, transmembrane pressure (TMP)and flow rate and find optimal operating conditions. The $N_2$-back flushing time (BT) was fixed at 40 sec, filtration times (FT) were changed in 4~32 min, TNP in $1.0~3.0kg_f/cm^2$ the flow celocities in 0.53~1.09cm/s. The optimal conditions were discussed in the viewpoints of dimensionless permeate flux ($J/J_0$), toal permeate volume ($V_T$) and resistance of membrane fouling ($R_f$). Optimal back-flushing period was BT/FT=0.167 (FT=8 min ), in which more $V_T$ was obtained than that in BT/FT=0.083 (FT=4 min) which was the most friquent back-flushing condition. Then rising TMP should increase the driving force, and more $V_T$ could be accumulated. And rising flow rate should decrease membrane fouling increase permeate flux, and more $V_T$could be produced. Average rejection rates of pollutants were higher than 95% for turbidity and 45~83% for $COD_{Cr}$, but rejection rates of total dissolved solid (TDS) were lower than 10%.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.6
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• pp.307-312
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• 2005

Since alpine upland in Pyungchang-gun has been typically applied every two or three years with saprolite, agricultural by-products are inputted to raise soil properties. Therefore, the effect of saprolite application on water quality in runoff and leachate should be monitored. To investigate water quality in runoff and leachate with various treatments of agricultural by-product, lysimeter with dimension of $0.85m{\times}1.75m{\times}0.30m$ was installed in Kangwon National University. Control, mixed compost with cow, chicken and sawdust by-product (CCSC), chicken manure by-product compost (CC), food waste by-product compost (FWC), and beer sewage sludge by-product compost (BSSC) at the rate of $10Mg\;ha^{-1}$ were mixed with soil in 25 cm depth, and water qualities in runoff and leachate were monitored from Jun. 4, 2004 to Oct. 18, 2004. EC ($0.8-2.2dS\;m^{-1}$) and concentrations of total N ($25-75mg\;L^{-1}$) and total P ($0.12-0.43mg\;L^{-1}$) were highest in both runoff and leachate of CC treatment. EC values in CC and FWC treatments continuously increased during lysimeter experiment, while total N and total P concentrations continuously decreased. Average total N concentrations in runoff taken from CCSC, FWC and BSSC treatments were 41, 34 and $37mg\;L^{-1}$, and in leachate were 35, 28 and $34mg\;L^{-1}$, respectively. Average total P concentrations were not different with different treatments. EC values in leachate were higher than those in runoff, and total N concentrations in runoff were higher than those in leachate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.51-54
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• 2000

The aim of this study was to collect fundamental data of taurine contained in the waste water from squid processing. The concentration of taurine and free amino acid was measured during each steps of squid processing as well as from waste of skinned and cooked squid, respectively. As a result, proline concentration reached to $800{\~}997\;mg/100\;g$ and taurine concentration reached to $730{\~}820 mg/100 g$. Comparing with raw squid, $60{\%}$ loss of free amino acid and Bleat reduction of taurine was detected in cooked squid. The concentration of free amino acid in waste water from skinned and cooked squid was $639.1 mg/100 ml, 470.7 mg/100 ml$, respectively. Among those free amino acids, taurine composed of $144.9 mg/100 ml and 117.3 mg/100 ml$ in-waste water from skinned and cooked squid, respectively, and these values were about $30{\%}$ of total free amino acids. Other major amino acids were isoleucine, alanine, fosine, leucine, glycine and. glutamate.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.228-235
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• 2012

A $N_2O_2$ Schiff base ligand, N,N'-bis(4-methoxysalicylidene)phenylendiamine (4-$CH_3O$-salphen) was synthesized. Using the 4-$CH_3O$-salphen, the spectrophoto-metric quantitative analysis of Cu(II) ion in aqueous solution was performed. The optimum condition for the quantitative analysis of Cu(II) ion was determined as the following; the concentration of 4-$CH_3O$-salphen is $2.0{\times}10^{-4}\;mol/L$, ratio between solvent DMSO and water is 50/50(v/v), pH is 5.5. After 1 hr water incubation at $55^{\circ}C$ and then the absorbance measurements at 388 nm, a calibration curve (${\varepsilon}=3.6{\times}10^4\;mol^{-1}cm^{-1}$) with a correlation coefficient ($R^2$=0.9963) was obtained in this condition. Using this optimized condition, the quantitative analysis of Cu(II) ion was performed with various samples such as hot spring water, semiconductor factory waste water and treated water from sewage treatment plant. The average value of the measured values agreed well with standard value with a range of 0.6~5.4%. The limit of determination was 31.77 ng/mL ($5.0{\times}10^{-7}\;mol/L$).

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.496-523
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• 2018

The objective of this study is to evaluate the economic feasibility of two fast pyrolysis and biooil upgrading (FPBU) plants including feed drying, fast pyrolysis by fluidized-bed, biooil recovery, hydro-processing for biooil upgrading, electricity generation, and wastewater treatment. The two FPBU plants are Case 1 of an FPBU plant with steam methane reforming (SMR) for $H_2$ generation (FPBU-HG, 20% yield), and Case 2 of an FPBU with external $H_2$ supply (FPBUEH, 25% yield). The process flow diagrams (PFDs) for the two plants were constructed, and the mass and energy balances were calculated, using a commercial process simulator (ASPEN Plus). A four-level economic potential approach (4-level EP) was used for techno-economic analysis (TEA) under the assumption of sawdust 100 t//d containing 40% water, 30% equity, capital expenditure equal to the equity, $H_2$ price of $1050/ton, and hydrocarbon yield from dried sawdust equal to 20 and 25 % for Case 1 and 2, respectively. TCI (total capital investment), TPC (total production cost), ASR (annual sales revenue), and MFSP (minimum fuel selling price) of Case 1 were $22.2 million, $3.98 million/yr, $4.64 million/yr, and $1.56/l, respectively. Those of Case 2 were $16.1 million, $5.20 million/yr, $5.55 million/yr, and $1.18/l, respectively. Both ROI (return on investment) and PBP (payback period) of Case 1(FPBU-HG) and Case 2(FPBU-EH) were the almost same. If the plant capacity increases into 1,500 t/d for Case 1 and Case 2, ROI would be improved into 15%/yr.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.337-343
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• 2005

Tapioca alcoholic distillery waste was utilized as dual purposes to produce citric acid and to reduce the amount of waste to be treated. Primarily an attempt was made to optimize the process conditions by Aspergillus niger in shake bath. The effects of pH, temperature, nitrogen and phosphorus sources on citric acid production were investigated. Maximum concentration of citric acid was made at temperature of $30^{\circ}C$ and pH of 4.3, while maximum cell dry weight was obtained at $35^{\circ}C$. The addition of methanol or ethanol to culture medium promoted citric acid production remarkably, but the addition of $NH_4NO_3,\;KH_2PO_4$ and Manganese as mineral source decreased the acid production.

• Journal of the Korean earth science society
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• v.45 no.1
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• pp.72-84
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• 2024

Recently, the vulnerability of water resources has been increasing owing to climate change, highlighting the importance of groundwater. In particular, the Nakdong River Basin, located in the southern part of Korea, experiences frequent water scarcity phenomena, such as droughts. This study analyzed the hydrogeological characteristics of the study area by examining groundwater and stream water in the Gwangrye Stream, downstream of the Nakdong River Basin, in August and October 2023. Therefore, we collected samples from 54 groundwater wells and five streams for water quality analysis. The results of the field tests indicated an increasing trend in electrical conductivity from upstream to downstream in the study area. Laboratory analyses confirmed that the concentration of Na increased from upstream to downstream more than that of Ca. In conclusion, both stream water and groundwater were influenced by anthropogenic contamination. These changes were closely related to land use in the study area. The upstream areas are primarily composed of forests, whereas the downstream areas are composed of industrial complexes, wastewater treatment facilities, and agricultural areas, which are likely to affect both stream water and groundwater.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2197-2204
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• 2000

Lignin is a major component of wastewater generated in the chemical processing of wood. Because it is recalcitrant, it inhibits biological treatment of wastewater of pulp manufacturing, especially high concentration of lignin may inhibit the anaerobic digestion. The objective of this study was to evaluate the toxicity of high molecular hardwood lignin (lignosulfonate, MW $\geq$ 20,000) on aceticlastic methanogens in the batch reactors at different temperatures with different sludge concentrations, using anaerobic serum bottles. The hardwood lignin was found to inhibit anaerobic conversion of acetate to methane and carbon dioxide, shown with a long lag-phase before methanogenesis started. The methanogens assumed not to be able to acclimate to the lignin were found to be acclimated slowly in the batch experiments, finally reaching non-toxic levels in which methane production could start. The hardwood lignin was found not to be bacteriocidal but bacteriostatic to aceticlastic methanogens. Hardwood lignin(lignosulfonate) at 1.3, 2.6, and 3.9%(w/w) inhibited the acetateutilizing methanogens of anaerobic digester sludge by 14.5, 17.8, 21.1 days(in noninhibitory condition it took 10 days) to produce the same amount of methane. The inhibitory effect of lignin was examined at temperature ranges of $30^{\circ}C$ to $50^{\circ}C$. When 2.6% of lignin was contained in wastewater, methane production was highest at $30^{\circ}C$ during initial 8 days. At $4^{\circ}C$, methane production rapidly increased after 12 days of digestion, the value became higher than that at $30^{\circ}C$ after 14 days. However, the methane production was completely inhibited during whole digestion period at $50^{\circ}C$. High ratio of lignin concentration to initial anaerobic sludge concentration gave tolerance to the inhibition. In this experiment, high molecular hardwood lignin was not degraded and decolorized.