• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.2
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• pp.35-44
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• 1986

This paper is a basic study of the experimental results for the treatment of ammonia-nitrogen in the septic tank effluent. The substrates in this experiment are actual septic tank effluent and synthetic waste-water which is similar to septic tank effluent containing a considerable amount of nitrogenous component. Experiments were conducted for organic removal and nitrification using various recycle ratio and hydraulic retention time at each stage. The results obtained show that organic removal rate was above 80% in the 1st and 2nd stage, but as nitrification process was proceeded, above 90% of ammonia-nitrogen was removed in the 3rd and 4th stage. In these cases, the recycle ratio and HRT were found 30 and 7 hrs respectively. In the relation of $NH_4{^+}-N$ removal to $NO_3{^-}-N$ formation in the synthetic waste-water and septic tank effluent, when $1mg/{\ell}$ of $NH_4{^+}-N$ was removed, $NO_3{^-}-N$ formations were $0.95mg/{\ell}$ and $0.82mg/{\ell}$ respectively. And kinetics of nitrification using Biological Fluidized Bed was discussed also.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.4
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• pp.460-465
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• 2007

In this study, the removal characteristic of ammonia nitrogen and behavior of nitrogen was investigated using Leclercia adecarboxylata, which was derived from the culture contaminated by ammonia nitrogen of high concentration. The method of ammonia nitrogen removal was not biological nitrification and denitrification but elimination of nutrient salt with internal synthesis of microorganisms which use ammonia nitrogen as substrate. L. adecarboxylata(one of ammonia synthesis microorganisms) was highly activated and showed the most high removal efficiency in free salt condition but the removal efficiency decreased badly in salt concentration of more than 4%. About 80 mg/L of $NH_3-N$ was mostly removed within 20 hours and 500 mg/L of $NH_3-N$ showed less then removal efficiency of 50% because carbon source was not enough. However, ammonium nitrogen concentration was decreased again when the carbon source was inserted additionally thus, ammonium nitrogen removal efficiency by L. adecarboxylata, was related to amount of carbon source. pH decreased from 8.0 to 6.36 according to growth of L. adecarboxylata. Concentration of nitrite nitrogen and nitrate nitrogen did not increase and TKN concentration showed no variation while ammonia nitrogen was removed by L. adecarboxylata. In addition to, when content of protein in organic nitrogen was measured, protein was not detected at the beginning of microorganism synthesis but protein of 193.1 mg/L was detected after 48 hours. Hence, ammonium nitrogen was not decomposed as nitrate nitrogen and nitrite nitrogen but synthesized by L. adecarboxylata, which has excellent ability of nitrogen synthesis and can threat ammonia nitrogen of high concentration in wastewater.

• Resources Recycling
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• v.13 no.3
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• pp.3-11
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• 2004

Basic studies have been conducted regarding the crystal formation of hydroxyapatite which was produced in the treatment process of phosphate-containing wastewater using calcium ions as the precipitating agent for its employment as the material for artificial bones. The precipitation of hydroxyapatite were conducted in the synthetic solution which simulating human body fluid for its increased applicability. Ca($NO_3$)$_2$$.$$4H_2$O and ($NH_4$)$_2$$HPO_4$ were employed for the precipitation of hydroxyapatite and its composition was analyzed after drying at 80oC. The thermal behavior of precipitate was investigated by examining the change in its crystalline structure according to the sintering temperature. DTA/TG analysis showed that the escape of moisture from the precipitate occurred at ca. $100^{\circ}C$ and the decomposition of ammonia and the evaporation of lattice water were brought about at around $250^{\circ}C$. X-ray diffraction analysis indicated that the thermally treated precipitate consisted mainly of hydroxyapatite. For dried precipitate, the bonds in the component materials which used for the precipitate formation were observed by FT-IR, and after thermal treatment the major bonds in the precipitate were shown to be $OH^{-}$, $PO_4^{3-}$ , and $CO_3^{ 2-}$ , which were main comprising bonds of hydroxyapatite.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.590-594
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• 2005

In this study, the wastewater treatment was conducted to evaluate the removal efficiency of total nitrogen from synthetic wastewater in the F-STEP PROCESS $(anaerobic{\rightarrow}\;oxic\;{\rightarrow}\;anoxic)$ with loess ball as support metrics. The average removal efficiencies of total nitrogen and ammonia nitrogen were $83.0\%\;and\;84.4\%$, respectively. The average nitrification efficiency at the oxic area was $60.9\%$ in the pH range of effluent water between 4.8 and 6.0. On the other hand, in the case of pH range of effluent water between 6.5 and 7.5, the denitrification efficiency at the anoxic area was $96.3\%$. The average concentration of COD was 12.8 ppm and the removal efficiency of COD in the F-STEP PROCESS were $96.3\%$. In the case of SS, the average concentration was $7.0\%$ at the effluent.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.64-78
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• 2011

Surface of hydrophobic polyethylene membrane was modified to become hydrophilic by ion beam irradiation. Submerged membrane filtration reactors contained pristine membrane or surface-modified membrane and the influent to reactors was pickled radish wastewater. The objectives of this study was to investigate the variation of flux and pressure and the characteristics of pollutant removal such as organics, suspended solids and nutrients with time. The result of experiments using intermittent pristine membrane showed the occurrence of severe fouling by increasing permeate pressure rapidly in case of pickled radish wastewater but in synthetic wastewater, this phenomenon was not occurred. In experiments of variation flux after chemical cleaning and water cleaning in pristine membrane, chemical cleaning must be necessary for renewals of pollutant membrane. Performance of intermittent operation is higher than that of continuous operation. Reaching fouling time in the case of surface-modified membrane is 6 times as long as pristine membrane. According this reason, replacement expense of surface-modified membrane could be 1/6 of that of pristine membrane. Effluent from this process was relatively good water quality and performance in the removal efficiency of SS, nitrogen and phosphorus was particularly higher.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.1
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• pp.63-68
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• 1982

This study was aimed ultimately to develop an adsorption process treating heavy metal industrial wastewater by utilizing domestically abundant natural zeolite and the study was conducted in a series of investigations. Presented if1 this paper are the results of the preliminary batch mode test. Factors affecting an adsorption process of heavy metals of aqueous waste stream by zeolite are numerous. Factors such as hydrogen ion concentration and temperature are taken into consideration in the investigation to evaluate adsorptive capacity. The mechanisms of adsorption may better be described by an evaluation of adsorption isotherm andi of adsorption kinetics. It is observed from the preliminary investigation that an optimum adsorption occurs at higher pH's than 4. It is further demonstrated that $Cd^{+2}$ adsorption by zeolite follows the BET model better than the Freundlich and the Langmuir model and that the reaction time of at least 10 minutes is required. It is interesting to note that higher adsorptive capacity was found at higher temperature, suggesting that the adsorption is not only due to simple physisorption but also due to chemisorption.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.254-263
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• 1993

The industry of amino acids has developed for the synthetic methods, zymotechnics from the methods of extraction. In the present, part of amino acids (L-cystine, L-tyrosine, etc.) is manufactured by the methods of extraction, but most of amino acids is produced by synthetic methods, zymotechnics. Among the methods, the synthetic methods use of cyanic acid, which generate a large of waste water by acid or alkali in hydrolysis. In this point of view, improved new synthetic methods are demanded for being the influence of environment. This article Introduces new synthetic methods of phenyl alnine, further more, the recent of research results are introduced to prepare the derivative ${\alpha}-keto$ acids of precursor for preparing more than particular amino acids.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.267-274
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• 2022

Excess nitrogen (N) flowing from livestock manure to water systems poses a serious threat to the natural environment. Thus, livestock wastewater management has recently drawn attention to this related field. This study first attempted to obtain the optimal conditions for the further volatilization of NH₃ gas generated from pig wastewater by adjusting the amount of injected magnesia (MgO). At 0.8 wt.% of MgO (by pig wastewater weight), the volatility rate of NH₃ increased to 75.5% after a day of aeration compared to untreated samples (pig wastewater itself). This phenomenon was attributed to increases in the pH of pig wastewater as MgO dissolved in it, increasing the volatilization efficiency of NH₃. The initial pH of pig wastewater was 8.4, and the pH was 9.2 when MgO was added up to 0.8 wt.%. Second, the residual ammonia nitrogen (NH₄⁺-N) in pig wastewater was removed by precipitation in the form of struvite (NH₄MgPO₄·6H₂O) by adjusting the pH after adding MgO and H₃PO₄. Struvite produced in the pig wastewater was identified by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis. White precipitates began to form at pH 6, and the higher the pH, the lower the concentration of NH₄⁺-N in pig wastewater. Of the total 86.1% of NH₄⁺-N removed, 62.4% was achieved at pH 6, which was the highest removal rate. Furthermore, how struvite changes with pH was investigated. Under conditions of pH 11 or higher, the synthesized struvite was completely decomposed. The yield of struvite in the precipitate was determined to be between 68% and 84% through a variety of analyses.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.69-70
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• 2001

알루미늄판의 보호피막을 제거하였을 때, 은판의 표면적이 넓을수록, 알루미늄판 표면적이 넓을수록, 염화물 농도가 높을수록 인 제거에 효과적이었고 연속식 실험에서는 HRT 12시간에서도 $PO_4$-P 1mg/$\ell$ 이하로 제거되었다.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.436-442
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• 2017

This study was conducted to develop a wastewater treatment system to remove organic matter, nitrate nitrogen, and phosphate ion in synthetic wastewater. COD was removed almost 100% by the oxidation reaction of HClO and nitrate nitrogen was reduced to ammonia by electrolysis treatment, but ammonia was reoxidized into nitrate nitrogen by HClO treatment. Ammonia was removed almost 100% by heating evaporation and no ammonia was reoxidized into nitrate by HClO treatment. Phosphate ion could be removed by precipitation treatment by forming metal complex according to pH. Through electrolysis treatment and HClO treatment, removal efficiencies of COD 99.5%, nitrogen 97.3% and phosphorus 91.5% were obtained.