• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.99-107
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• 2000

In this article, the removal of surfactant by ozone and BAC was studied. Batch and pilot tests were carried out for these studies. In batch tests, efficiency of ozone oxidation process was evaluated for LAS(Linear Alkylbenzen Sulfonate) and SLS(Sodium Lauryl Sulfate) removal. Under oxidant conditions, the removal of LAS was more effective than that of SLS. The removal of surfactant was more enhanced with increasing pH in oxidant systems. Pilot tests are carried out with BAC single process and ozone oxidation/BAC combined process. The removal of LAS was more effective in ozone oxidation/BAC combined process than BAC single process about 10-20%. In the case of SLS, the efficiency of BAC single process was similar to that of ozone oxidation BAC combined process. According to temperature, the removal efficiency of SLS changed from 70% to 95% and initial concentration of surfactant had no effects on removal efficiency of SLC under applied temperature above $15^{\circ}C$.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2207-2219
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• 2018

Activated carbon (AC) was synthesized from Phoenix dactylifera stones and then modified by $CoFe_2O_4$ magnetic nanocomposite for use as a Cr(VI) adsorbent. Both $AC/CoFe_2O_4$ composite and AC were fully characterized by FTIR, SEM, XRD, TEM, TGA, and VSM techniques. Based on the surface analyses, the addition of $CoFe_2O_4$ nanoparticles had a significant effect on the thermal stability and crystalline structure of AC. Factors affecting chromium removal efficiency like pH, dosage, contact time, temperature, and initial Cr(VI) concentration were investigated. The best pH was found 2 and 3 for Cr adsorption by AC and $AC/CoFe_2O_4$ composite, respectively. The presence of ion sulfate had a greater effect on the chromium sorption efficiency than nitrate and chlorine ions. The results illustrated that both adsorbents can be used up to seven times to adsorb chromium. The adsorption process was examined by three isothermal models, and Freundlich was chosen as the best one. The experimental data were well fitted by pseudo-second-order kinetic model. The half-life ($t_{1/2}$) of hexavalent chromium using AC and $AC/CoFe_2O_4$ magnetic composite was obtained as 5.18 min and 1.52 min, respectively. Cr(VI) adsorption by AC and $AC/CoFe_2O_4$ magnetic composite was spontaneous and exothermic. In general, our study showed that the composition of $CoFe_2O_4$ magnetic nanoparticles with AC can increase the adsorption capacity of AC from 36 mg/L to 70 mg/L.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.738-742
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• 1996

An efficient packed-bed type biofilm reactor charged with immobilized phototrophs was developed to treat organic wastewater at an extremely high volumetric loading rate. The packed bed reactor (PBR) charged with porous ceramic beads was superior to a fluidized-bed reactor suspended with activated carbon powders in terms of many aspects such as BOD removal efficiency, operational stability, and overall economics. For wastewater with BOD concentration as high as 20, 000mg/l, the BOD removal efficiency was maintained above 90% when the hydraulic retention time (HRT) was longer than 1 day. The allowable volumetric BOD loading rate of this reactor (20gBOD/l day) is more than ten-folds higher than that of an ordinary activated sludge method. The behaviour of the reactor was represented well by a Monod type kinetic equation with a maximum specific BOD loading rate(P) of 22.2gBOD/l day and a half saturation constant(K$_{s}$) of 1, 750 mgBOD/l.

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.172-179
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• 1999

In this research, biological treatability test was conduced using seawater flocculated tannery wastewater by fixed biofilm reactor. During one cycle, the removal efficiency of organic corbon obtained with fixed biofilm process for treating tannery wastewater was considerably greater than that with activated sludge process. As the hydraulic retention time increased form 0.5day to 4day, removal efficiency of organic carbon was increased from 72% to 87.3%. Attached biomass in media increased with influent organic loading up to 29g MLSS/L, that could reduce the specific organic loading rate. The continual measurement of attached biomass was possible for the operation of the biofilm reactor. Equal and low nitrication rates were observed in both suspended growth activated sludge process and fixed biofilm process, despite commercial nitrifier was seeded. Through the process of treating the tannery wastewater, EC50 values which is measured by the use of Ceriopdaphnia dubia, were decreased to the extent of 50% after treatment of seawater flocculation and of 83% after biological treatment, respectively, compared to those of the untreated wastewater.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.599-601
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• 2010

• Journal of Korean Society of Water and Wastewater
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• v.37 no.4
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• pp.177-186
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• 2023

Perfluorooctanoic acid(PFOA) was one of widely used per- and poly substances(PFAS) in the industrial field and its concentration in the surface and groundwater was found with relatively high concentration compared to other PFAS. Since various processes have been introduced to remove the PFOA, adsorption using GAC is well known as a useful and effective process in water and wastewater treatment. Surface modification for GAC was carried out using Cu and Fe to enhance the adsorption capacity and four different adsorbents, such as GAC-Cu, GAC-Fe, GAC-Cu(OH)₂, GAC-Fe(OH)₃ were prepared and compared with GAC. According to SEM-EDS, the increase of Cu or Fe was confirmed after surface modification and higher weight was observed for Cu and Fe hydroxide(GAC-Cu(OH)₂ and GAC-Fe(OH)₃, respectively). BET analysis showed that the surface modification reduced specific surface area and total pore volumes. The highest removal efficiency(71.4%) was obtained in GAC-Cu which is improved by 17.9% whereas the use of Fe showed lower removal efficiency compared to GAC. PFOA removal was decreased with increase of solution pH indicating electrostatic interaction governs at low pH and its effect was decreased when the point of zero charges(pzc) was negatively increased with an increase of pH. The enhanced removal of PFOA was clearly observed in solution pH 7, confirming the Cu in the surface of GAC plays a role on the PFOA adsorption. The maximum uptake was calculated as 257 and 345 ㎍/g for GAC and GAC-Cu using Langmuir isotherm. 40% and 80% of removal were accomplished within 1 h and 48 h. According to R², only the linear pseudo-second-order(pso) kinetic model showed 0.98 whereas the others obtained less than 0.870.

• Journal of Environmental Science International
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• v.18 no.2
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• pp.205-213
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• 2009

A laboratory experiment was conducted to investigate nitrogen removal from plating wastewater by a soil reactor. A combination of soil, waste oyster shell and activated sludge were used as a loading media in a soil reactor. The addition of 20% waste oyster shell and activated sludge to the soil accelerated nitrification (88.6% ${NH_4}^{+}-N$ removal efficiency) and denitrification (84.3% ${NO_3}^{-}-N$ removal) in the soil reactor, respectively. In continuous removal, the influent ${NH_4}^{+}-N$ was mostly converted to nitrate nitrogen in the nitrification soil reactor and only a small amount of ${NH_4}^{+}-N$ was found in the effluent. When methanol was added as a carbon source to the denitrification soil reactor, the average removal efficiency of ${NO_3}^{-}-N$ significantly increased. The ${NO_3}^{-}-N$ removal by methanol addition in the denitrification soil reactor was mainly due to denitrification. The phosphorus was removed by the waste oyster shell media in the nitrification soil reactor. Moreover, the phosphorus removal in the denitrification soil reactor was achieved by synthesis of bacteria and the denitrification under anaerobic conditions. The approximate number of nitrifiers and denitrifiers was $3.3{\times}10^5\;MPN/g$ soil at a depth of $1{\sim}10\;cm$ and $3.3{\times}10^6\;MPN/g$ soil at a depth of $10{\sim}20\;cm$, respectively, in the soil reactor mixed with a waste oyster shell media and activated sludge.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.1
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• pp.47-55
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• 2015

Recently, the production of taste and odor (T&O) compounds is a common problem in water industry. Geosmin is one of the T&O components in drinking water. However, geosmin is hardly eliminated through the conventional water treatment systems. Among various advanced processes capable of removing geosmin, adsorption process using granular activated carbon (GAC) is the most commonly used process. As time passes, however GAC process changes into biological activated carbon (BAC) process. There is little information on the BAC process in the literature. In this study, we isolated and identified microorganisms existing within various BAC processes. The microbial concentrations of BAC processes examined were $3.5{\times}10^5$ colony forming units (CFU/g), $2.2{\times}10^6CFU/g$ and $7.0{\times}10^5CFU/g$ in the Seongnam plant, Goyang plant and Goryeong pilot plant, respectively. The dominant bacterial species were found to be Bradyrhizobium japonicum, Novosphingobium rosa and Afipia broomeae in each plants. Removal efficiencies of $3{\mu}g/L$ geosmin by the dominant species were 36.1%, 36.5% and 34.3% in mineral salts medium(MSM) where geosmin was a sole carbon source.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.700-705
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• 2012

The present study is to explore the possibility of utilizing loess and fly ash as well as activated carbon for the adsorptive removal of T-N and T-P in water. Here, we investigated adsorption efficiency and Freundlich constants k and 1/n of each adsorbent. It was found that fly ash has not adsorptive capability for both T-N and T-P in water. Adsorption of T-N from water by loess has not occurred, but showed that adsorption efficiency for T-P reached approximately 57.5% at equilibrium time of 24 hr and room temperature. Activated carbon was shown to be an effective adsorbent for adsorption of T-N from water. Freundlich constant 1/n value of activated carbon represented that adsorptive capability of activated carbon is almost equivalent to loess.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.406-409
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• 2000

For the effective treatment of dye-processing wastewater, JLR(Jet-Loop Reactor) with active carbon supports were investigated. BOD removal efficiency was found as 99% when influent BOD concentration of dye-processing wastewater was 400 mg/L. $COD_{Mn}$ of effluent removal efficiencies were found as 86${\sim}$ 89% when these of activated sludge reactor were 62${\sim}$72%. Also, color removal efficiencies were found as 84${\sim}$87% when these of activated sludge reactor were 72%${\sim}$77%. After JLR with active carbon supports had been used, all of the $COD_{Mn}$, $COD_{Cr}$ and color removal efficiencies Increased when chemical precipitation was done. Consequently, JLR with active carbon supports was proved to be more excellent than the activated sludge reactor.