• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.1
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• pp.31-37
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• 2002

This paper was investigated to clarify the possibility of a biodegradation of materials adsorbed on different porous granular-activated carbons (GACs) such as coal-& coconut-based GAC. Total organic carbon, humic substance and ammonia were used to compare their removal efficiencies. The objective of this study is to determine the adsorption capacity of bioregenerated GAC. When raw water reacted with chloride, the yield of THMs increased as a function of the input amount of chloride. The formation of trihalomethanes (THMs) was investigated in water treated with chlorine when humic acid was used as THM precursor. As the input amount of chloride in raw water increased by two or five-fold to remove the $NH_3$, the chloroform of the THMs significantly increased also five or ten-fold. It was found that the chloroform was significantly removed by the treatment of biological activated carbon (BAG) in comparison with the ozone treatment, and the removal efficiency of THMs in coal-typed GAC was $10-30\%$ better than coconut-typed GAC due to the biological degradation on the surface of the activated carbons.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.4
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• pp.51-58
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• 1997

GAC(Global Avalanche Charateristics)은부울함수가 확산특성 관점에서 얼마나 우수한지를 전체경우에 대하여 나타내는 특성으로 Zhang-Zheng(1995) 에 의해서 제안되었다. GAC개념이 등장하기 이전에는 부분적인 확산특성에 대하여만 연구를 하였으나 다른 암호학적인 특성과 연관하여 생각하면 전체적인 확산특성이 의미가 있다. Zhang-Zheng은 GAC을 측정하는 두가지 기준을 제시하고 이 기준에 대한 하한과 상한을 구하였으며 선형함수와 벤트함수에 대하여 이러한 상한과 하한이 달성됨을 증명하였다. 그러나 암호학적으로 의미가 있는 균형인 함수의 두가지 기준에 대한 하한과 상한은 밝혀지지 않았다. 본 논문에서는 부울함수가 균형인 함수의 두가지 기준에 대한 하한과 상한은 밝혀지지 않았다. 본 논문에서는 부울함수가 균형일 때 GAC을 측정하는 기준에 대한 하한을 제시한다. 이러한 하한 아직까지 미해결 문제로 남아있는 균형인 부울 함수의 비선형치에 대한 상한을 구하는데 새로운 방향을 제시할 수 있다.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.2
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• pp.235-248
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• 2014

The widespread occurrence of dissolved endocrine disrupting compounds(EDCs) and pharmaceutical active compounds(PhACs) in water sources is of concern due to their adverse effects. To remove these chemicals, adsorption of EDCs/PhACs on granular activated carbon(GAC) was investigated, and bisphenol A, carbamazepine, diclofenac, ibuprofen, and sulfamethoxazole were selected as commonly occurring EDCs/PhACs in the aquatic environment. Various adsorption isotherms were applied to evaluate compatability with each adsorption in the condition of single-solute. Removal difference between individual and competitive adsorption were investigated from the physicochemical properties of each adsorbate. Hydrophobicity interaction was the main adsorption mechanism in the single-solute adsorption with order of maximum adsorption capacity as bisphenol A > carbamazepine > sulfamethoxazole > diclofenac > ibuprofen, while both hydrophobicity and molecular size play significant roles in competitive adsorption. Adsorption kinetic was also controled by hydrophobicity of each adsorbate resulting in higher hydrophobicity allowed faster adsorption on available adsorption site on GAC. EDCs/PhACs adsorption on GAC was determined as an endothermic reaction resulting in better adsorption at higher temperature ($40^{\circ}C$) than lower temperature ($10^{\circ}C$).

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.19-25
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• 2011

Generally, the generation methods of cooling energy are electric air conditioning (EAC) and gas air conditioning (GAC). The EAC system is caused by increasing peak power during summer. Because the electric energy has a characteristic of non-storage, the peak electric load has been issued social problem annually whether the facility to supply is enough or not. Another way to supply cooling energy, GAC system is worked by gas energy. The absorption chiller and gas engine heat pump have been commercialized for cooling. However, the total capacity of GAC is much less than EAC and it almost depends on EAC for small market. This paper described the status of cooling energy consumption in domestic and expected the cooling energy to be consumed by electric and gas energy up to 2024 year. And also the benefit of GAC was analyzed with the case of its expansion and it was aimed to give background to fit the GAC policy.

• Journal of Environmental Science International
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• v.23 no.6
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• pp.1101-1109
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• 2014

In this study we followed biofilm formation and development in a granular activated carbon (GAC) filter on pilot-scale during the 12 months of operation. GAC particles and water samples were sampled from four different depths (-5, -25, -50 and -90 cm from surface of GAC bed) and attached biomass were measured with adenosine tri-phosphate (ATP) analysis and heterotrophic plate count (HPC) method. The attached biomass accumulated rapidly on the GAC particles of top layer throughout all levels in the filter during the 160 days (BV 23,000) of operation and maintained a steady-state afterward. During steady-state, biomass (ATP and HPC) concentrations of top layer in the BAC filer were $2.1{\mu}g{\cdot}ATP/g{\cdot}GAC$ and $3.3{\times}10^8cells/g{\cdot}GAC$, and 85%, 83% and 99% of the influent total biodegradable dissolved organic carbon ($BDOC_{total}$), $BDOC_{slow}$ and $BDOC_{rapid}$ were removed, respectively. During steady-state process, biomass (ATP and HPC) concentrations of middle layer (-50 cm) and bottom layer (-90 cm) in the BAC filter were increased consistently. Biofilm development (growth rate) proceed highest rate in the top layer of filter (${\mu}_{ATP}=0.73day^{-1}$; ${\mu}_{HPC}=1,74day^{-1}$) and 78%~87% slower in the bottom layer (${\mu}_{ATP}=0.14day^{-1}$; ${\mu}_{HPC}=0.34day^{-1}$). This study shows that the combination of different analytical methods allows detailed quantification of the microbiological activity in drinking water biofilter.

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.586-593
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• 2007

Seed coating by a phenazine-producing bacterium, Pseudomonas chlororaphis O6, induced dose-dependent inhibition of germination in wheat and barley seeds, but did not inhibit germination of rice or cucumber seeds. In wheat seedlings grown from inoculated seeds, phenazine production levels near the seed were higher than in the roots. Deletion of the gacS gene reduced transcription from the genes required for phenazine synthesis, the regulatory phzI gene and the biosynthetic phzA gene. The inhibition of seed germination and the induction of systemic disease resistance against a bacterial soft-rot pathogen, Erwinia carotovora subsp. carotovora, were impaired in the gacS and phzA mutants of P chlororaphis O6. Culture filtrates of the gacS and phzA mutants of P. chlororaphis O6 did not inhibit seed germination of wheat, whereas that of the wild-type was inhibitory. Our results showed that the production of phenazines by P. chlororaphis O6 was correlated with reduced germination of barley and wheat seeds, and the level of systemic resistance in tobacco against E. carotovora.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.723-731
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• 2000

In recent years, the amount and number of synthetic organic compounds(SOCs) discharged from various industries has been increasing. Granular activated carbon(GAC) adsorption is one of the best available technology to remove SOCs from water supplies and wastewater. In this paper competitive adsorption for binary mixture of 4-nitrophenol and phenol on reverse stratified tapered adsorber(RSTA) using GAC was studied. Two isotherm experiments were conducted, one for phenol and the other for 4-nitrophenol. The phenol data of binary mixture isotherm were not fitted to Freundlich isotherm. The competitive adsorption increased significantly with decreasing carbon dose and increasing adsorbate concentration. The RSTA was found to provide an increase in breakthrough time when decreasing flow rate, increasing angle and injection layers. The performance enhancement provided by RSTA can be exploited in separation and in the purification of fluids.

• Journal of Wetlands Research
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• v.17 no.2
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• pp.155-162
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• 2015

This study was conducted to assess the removal characteristics of taste and odor causing compounds(2-MIB and geosmin) and micro organic matters. GAC and BAC process consisting of Ozone/AOP and activated carbon was applied. As a result, the influent concentration of 2-MIB 159 ng/L and geosmin 371 ng/L were removed 42% and 86% by ozone 1.0 mg/L, and 58%, 90% by AOP(ozone 1.0 mg/L + $H_2O_2$ 0.5 mg/L). Also it showed less than 2 ng/L effluent in GAC process and 99.8% removal efficiency in BAC process. Therefore, BAC process combining ozone/AOP and GAC is effective for persistent removal of micro organic matters, taste and odor. It is needed for optimization of Ozone/AOP process according to influent concentrations.

• Membrane and Water Treatment
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• v.10 no.6
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• pp.471-484
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• 2019

The complex combination of organic contaminants in the wastewater made water treatment challenging; hence, organic matter in water bodies is usually measured in terms of organic carbon. Since it is important to identify the types of compounds when deciding suitable treatment methods, this study implemented a quantitative and qualitative analysis of the organic matter content in an actual graywater sample from Ulsan, Republic of Korea using mass spectroscopy (MS). The graywater was treated using adsorption to remove the organic contaminants. Using orbitrap MS, the organic matter content between an untreated graywater and the treated effluent were compared which yielded a significant formula count difference for the samples. It was revealed that CHON formula has the highest removal count. Isotherm studies found that the Freundlich equation was the best fit with a coefficient of determination ($R^2$) of 0.9705 indicating a heterogenous GAC surface with a multilayer characteristic. Kinetics experiments fit the pseudo-second order equation with an $R^2$ of 0.9998 implying that chemisorption is the rate-determining step between the organic compounds and GAC at rate constant of $52.53g/mg{\cdot}h$. At low temperatures, the reaction between GAC and organic compounds were found to be spontaneous and exothermic. The conditions for optimization were set to achieve a maximum DOC and TN removal which yielded removal percentages of 94.59% and 80.75% for the DOC and TN, respectively. The optimum parameter values are the following: pH 6.3, 2.46 g of GAC for every 30 mL of graywater sample, 23.39 hrs contact time and $38.6^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.9
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• pp.513-518
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• 2017

In this paper, the removal efficiency of THMs (Trihalomethanes) and DOC (Disolved organic carbon) was compared under different GAC (Granual activated carbon) filling methods. One method is "full filling method" in which column is fully filled with GAC at once and the other is "periodic cumulative method" in which column is partially filled with GAC (10, 20, 33 and 50% of total column volume) and added each ratio during 300 days. The effluent concentration of both THMs and DOC under full filling method was low during the initial period, however, steadily increased with operating time. In the contrast, with periodic cumulative method, it maintained (relatively) evenly during the operating period. Periodic cumulative method was more efficient for removing THMs than full filling method. However, when the ratio of chlorodibromomethane or bromoform among THMs was significantly higher than chloroform and bromodichloromethane, full filling method was more efficient than periodic cumulative method. Full filling method had benefit to total DOC removal and control of average DOC concentration in effluent. Overall, periodic cumulative method is more efficient to equalize the removal efficiency of THMs and DOC, so the more frequent refilling of column with small amount of GAC is more advantageous.