• Environmental Engineering Research
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• 제13권4호
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• pp.203-209
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• 2008

This paper presents the experimental results in five months operation from a combined anaerobic/oxic system treating swine waste with average concentrations in organic matter and nitrogen of 7,930 mgCOD/L and 671 mgTKN/L, respectively. The system was formed using an upflow anaerobic sludge blanket (UASB) reactor and oxic reactor connected in series with a recycling line of oxic effluents to UASB for its denitrification. The UASB reactor was operated at an organic volumetric loading rate (VLR) of $2.1{\sim}4.5\;kgTCOD/m^3$/day and the removal efficiency of TCOD was $66.3{\sim}85.4%$. The overall removal efficiency of TCOD was more than 99%. The oxic reactor was operated at a nitrogen VLR of $0.10{\sim}0.20\;kgTKN/m^3$/day and the nitrification efficiency was 75%. However, the complete denitrification was observed in the UASB reactor that was due to the optimal temperature and sufficient carbon source. The overall removal rate of TN was about 80%. About 76.2% of the influent COD mass was accountable in a COD mass balance at a level of VLR $3.64\;kgCOD/m^3$/day. The production rate of methane was $0.32\;LCH_4/gCOD_{removed}$ when influent organics, VLR, were recorded by $3.4{\sim}4.5\;kgCOD/m^3$/day.

• Environmental Engineering Research
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• 제25권1호
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• pp.80-87
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• 2020

Landfill waste decomposition generates a dark effluent named, leachate which is characterized by high organic matter content. To minimize these polluting effects, it becomes necessary to develop an effective landfill leachate treatment process. The objective of this study was to evaluate the performance of an innovative approach based on air stripping, anaerobic digestion (AD) and aerobic activated sludge treatment. A reduction of 80% of ammonia and an increase of carbon to nitrogen ratio to 25 were obtained, which is a suitable ratio for AD. This latter AD was performed in fixed bed reactor with progressive loading rate that reached 2 and 3.2 g COD/L/d for the raw and diluted leachate (1:2), respectively. The anaerobic treatment led to significant removal of chemical oxygen demand (COD) and biogas production, especially for the diluted leachate. The COD removal was of 78% for the raw leachate and a biogas production of 4 L/d with 70% methane content. The use of the diluted leachate led to 81% of COD removal and 7 L/d biogas with 75% methane content. It allowed a removal of 77% COD and more than 97% of the organic compounds present in the initial leachate sample.

• 환경위생공학
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• 제13권1호
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• pp.44-56
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• 1998

This study was performed to investigate the reaction characteristics of piggery wastewater for biological nutrient removal. The reaction characteristics were discussed the fraction of organics, the behavior of nitrogen, nitrification, denitrification, and the behavior of phosphorus. The fraction of readily biodegradable soluble COD was 11-12 percent. The ammonia nitrogen was removed via stripping, nitrification, autotrophic cell synthesis, and heterotrophic cell synthesis. The removal percents by each step were 12.1%, 68.9%, 15.0%, and 4.0%, respectively. Nitrification inhibition of piggery wastewater was found to occur at an influent volumetric loading rate over 0.2 NH$_{3}$-N kg/m$^{3}$/d. Denitrification rates were the highest in the raw wastewater and the lowest in the anaerobic effluent. The denitritation of piggery wastewater came out to be possible, and the rate of organic carbon consumption decreased about 10 percent. The phosphorus removed was released in the form of ortho-p in the aerobic fixed biofilm reactor, it was caused by autooxidation. The synthesis and release of phosphorus were related to the ORP and the boundary value for the phase change was about 170mV. In the synthesis phase, the phosphorus removal rate per COD removed was 0.023mgP$_{syn}$/mgCOD$_{rem}$. The phosphorus contents of the microorganism were 4.3-6.0% on a dry weight basis.

• 환경위생공학
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• 제16권2호
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• pp.32-37
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• 2001

The purpose of this study was to investigate the created liquid post-acid fermentation of usability of denitrification as exterior carbon sources by pH control. The time of acid fermentation of food waste, the slower loading capacity of organic matter, the faster decomposition rate, but the density of generation Volatile Fermentation Acids(VFAs), was weak and, $SBOD_{5}$ : ST-N rate and $SBOD_{5}/SCOD_{Cr}$ rate was low. Between TS and VS, VS was decreased to 4.5th day fast, and then was decreased slowly. 1.5 days after stating the experiments, $SCOD_{Cr}$, $SBOD_{5}$, STOC and $VFA_{s}$ was decreased of increased slowly, and then increased fast. And after showing the highest density, it was tended to decreased fast. At the time of $SBOD_{5}$ with the highest density, at $SBOD_{5}$ : ST-N ratio, $R_1$ was 303:1, $R_2$ was 319:1, $R_3$was the highest. After studying $SBOD_{5}$ : ST-N ratio and $SBOD_{5}/SCOD_{Cr}$ ratio, as a carbon source of biological denitrification it was profitable composition ratio.

• 한국환경과학회지
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• 제13권7호
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• pp.675-680
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• 2004

This study was conducted to remove organics and nutrients using 2 stage intermittent aeration reactor. First reactor, using suspended microbial growth in intermittent aeration instead of anaerobic reactor in the typical BNR process, used minimum carbon source to release P, and it was possible to reduce ammonia loading going to second reactor. In the second reactor, using moving media intermittent aeration, it was effective to reduce nitrate in non-aeration time by attached microorganisms having long retention time. In aeration time, nitrification and P uptake were taken place simultaneously. From the experiment, two major results were as follows. First, the removal of organics was more than 90%, and optimum aeration/non-aeration time ratio for organic removal was corresponded with aeration/non-aeration time ratio for nitrogen removal. Second, in the first reactor, optimum aeration/non-aeration time ratio was 15/75 (min.) because it was necessary to maintain 75 min. of non-aeration time to suppress of impediment of return nitrate and to lead release of phosphate. In the second reactor, optimum aeration/non-aeration time ratio was 45/90 (min.).

• Environmental Engineering Research
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• 제23권1호
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• pp.70-75
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• 2018

A pilot scale anaerobic fixed-bed with a reactor volume of $2.8m^3$ was built to treat slaughterhouse wastewater. Bamboo rings were chosen as support media mainly because of their cheaper price in underdeveloped countries. Even with their lower porosity and specific surface, the reactor performance showed a maximum 95% COD removal efficiency at an organic loading rate (OLR) of $1kg\;COD/m^3-d$ with its corresponding hydraulic retention time (HRT) of 7.5 d. At a higher OLR of $4.0kg\;COD/m^3-d$, the COD removal efficiency of 75% was achieved with an HRT of 2 d. No big difference in COD removal efficiencies was found between the reactors operated in both upflow and downflow modes. Their operational behavior and effluent characteristics were similar. The effluent COD/TKN ratio of 6.67 at an OLR of $4.0kg\;COD/m^3-d$ was only marginal acceptable range for a subsequent biological denitrification process. Otherwise carbon supplementation is required at a lower OLR.

• 한국환경과학회지
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• 제11권6호
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• pp.569-576
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• 2002

Anaerobic/aerobic reactor system was used to treat a synthetic wastewater with glucose as carbon sources(0.38~2.29 kg COD/m3.day) and Acid Red 14(1.05 "24.00 g Acid Red 141m3.day, color degree of 570 ~ 1710). COD removal efficiency by the anaerobic stage in operation period were above 90 % organic loading rate of 0.38 ~ 2.29 kg COD/m3.day(except, adaptation period) and the removal efficiency of the whole system were above 96 %. The decolorization of the Acid Red 14 was through the alteration of the dye structure(or cleavage of the Azo bond) during the anaerobic treatment. In the A/A system, the anaerobic stage played an essential role in removing both color and COD. In addition it also improves biodegradability of dye f3r further aerobic treatment. After operation, average MLSS concentration of anaerobic sludge reactor, anaerobic fixed-bed reactor and aerobic fixed-bed reactor were 17100mg/L, 20000mg/L, and 10000mg/L, respectively.

• 산업기술연구
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• 제26권A호
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• pp.199-205
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• 2006

Ozone alone and catalytic ozone processes were introduced for treatment of humic acid, which is representative refractory organic compound. The treatment efficiencies of humic acid in each process were analyzed in pH variation, DOC removal, and $UV_{254}$ decrease. Mn loaded GAC catalyst was prepared by loading potassium permanganate onto the granular activated carbon surface. BCM-GAC and BCM-Silica gel catalyst were prepared by BCM. $UV_{254}$ decrease in all processes was comparatively high with efficiency over 87%. DOC removal in ozone/GAC process was the highest with 78%, and removal rates for other processes followed the order ozone/BCM-GAC(62%) > ozone/BCM-silica gel(45%) > ozone/silica gel(43%) > ozone/Mn Loaded GAC(42%) > ozone alone(37%).

• Korean Chemical Engineering Research
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• 제50권5호
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• pp.885-889
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• 2012

본 연구에서는 활성탄소의 이산화탄소 흡착 능력을 향상시키기 위한 아민과 금속산화물 첨가제에 관하여 고찰하였다. 표면 처리한 활성탄소의 물리화학적 특성은 X-ray photoelection specstroscopy (XPS), 질소등온흡착곡선, X-ray diffraction (XRD), BET 장치를 이용하여 분석하였다. 실험결과, 활성탄소 표면의 아민 기능기는 산성가스인 이산화탄소를 선택적으로 흡착하기 위한 염기성 자리로 작용하며, 2차아민을 갖는 기능기가 1차아민에 비하여 이산화탄소흡착능력이 우수함을 확인하였다. 활성탄소에 첨가된 금속산화물은 표면에서 전자 도우너(electron donor) 역할을 하며 알칼리 특성을 지니고, 아민 기능기와 유사하게 이산화탄소 가스와 산-염기 반응을 유도한다. 금속산화물 표면처리를 했을 경우 순수한 활성탄소와 비교하여 이산화탄소 흡착 용량이 85% 증가하였으며, 이러한 결과로 미루어 볼 때 금속산화물 첨가제는 활성탄소의 이산화탄소 흡착능력을 향상시키기 위한 목적으로 아민 첨가제와 병행하거나 대체할 수 있는 물질로 기대된다.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1720-1726
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• 2014

(S)-Alanine Racemase Chiral Analogue ((S)-ARCA) was used as an efficient adsorbent for the selective separation of D-amino acids (D-AAs), which are industrially important as chiral building blocks for the synthesis of pharmaceutical intermediates. The organic phase, containing (S)-ARCA adsorbent and phase transfer reagents, such as ionic liquid type molecules (Tetraphenylphosphonium chloride (TPPC), Octyltriphenylphosponium bromide (OTPPBr)), were coated on the surfaces of mesoporous carbon supports. For the immobilization of chiral adsorbents, meso/macroporous monolithic carbon (MMC), having bimodal pore structures with high surface areas and pore volumes, were fabricated. The separation of chiral AAs by adsorption onto the heterogeneous (S)-ARCA was performed using a continuous flow type packed bed reactor system. The effects of loading amount of ARCA on the support, the molar ratio of AA to ARCA, flow rates, and the type of phase transfer reagent (PTR) on the isolation yields and the optical purity of product D-AAs were investigated. D-AAs were selectively combined to (S)-ARCA through imine formation reaction in an aqueous basic solution of racemic D/L-AA. The (S)-ARCA coated MMC support showed a high selectivity, up to 95 ee%, for the separation of D-type phenylalanine, serine and tryptophan from racemic mixtures. The ionic liquids TPPC and OTPPBr exhibited superior properties to those of the ionic surfactant Cetyltrimethyl ammonium bromide (CTAB), as a PTR, showing constant optical purities of 95 ee%, with high isolation yields for five repeated reuses. The unique separation properties in this heterogeneous adsorption system should provide for an expansion of the applications of porous materials for commercial processes.