• 한국물환경학회지
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• 제21권2호
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• pp.158-168
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• 2005

In this study, the discharging effluents from have been 9 municipal wastewater treatment plants surveyed for 1 year-period. Statistics including probability distribution, cumulative occurrence concentration and other statistical parameters were presented. In addition, treatment performance and its stability were also discussed. Most of the plants, have an operational problem of high soluble organic content in the secondary effluent which may be associated with the integrated treatment of human and livestock manures. Nitrogen concentration in the effluents were usually higher during the period of summer and winter. It was found that this is mainly due to lack of the proper C/N ratio during the summer, or/and the effects of low temperature and less dilution by dry weather during the winter. Phosphorus concentration is sharply increased in June. Discussion with plant operators told that it is due to the dissolution of phosphate from the sludge accumulated in the primary settling tanks from the early spring to june. During this period, usually, sludge treatment line is highly overloaded with flush-outs of the sediments also stored in the bottom of combined sewer due to the low flow during winter season. Most of the plants can meet new effluent discharge limits of the nitrogen and phosphorus, and total coliform without further treatment.

• 한국양식학회지
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• 제10권3호
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• pp.335-346
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• 1997

연구는 순환 여과식 어류 양식 시설에 일반적으로 이용되고 있는 선라이트 골판을 여과재료로 한 침지식 여과조의 적정 탈질 조건을 구명하기 위해 외부 탄소원으로 메탄올과 글루코스를 사용하여 수리학적 체류 시간 (hydraulic retention time, HRT)과 COD에 대한 NO 하(3) 상(-)-N 비율 변화에 따른 적정 탈질 조건을 알아보았다. 질산성 질소와 총무기질소(TIN)의 제거 효율은 HRT 4 시간보다는 8 시간이 좋았으며, 글루코스보다는 메탄올을 이용한 것이 좋았다(P<0.05). 최대 질산성 질소 제거는 글루코스의 경우 HRT 8 시간과 C : N 비율 4일 때 86.3%였고, 메탄올은 HRT 8시간과 C : N 비율 5일 때 97.8%, 6일 때 92.2%를 보여 C : N 비율 5가 가장 최적인 것으로 나타났다. 최대 총무기질소 제거 효율은 HRT 8 시간일 때 C : N 비율 5에서 글루코스는 71.5%, 메탄올은 96.9%을 보였다. 탈질화에 필수적인 혐기적 조건은 HRT 8 시간과 C : N 비율 5 이상이 되었을 때 이루어진 것으로 보아 적정 C : N 비율과 혐기적 조건이 이루어졌을 때의 최적의 탈질 효율을 보이는 것으로 나타났다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.553-556
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• 2000

Possibility of biological nitrogen treatment was tested in wastewaters with low C/N ratio. Chlorella kessleri was inoculated at $10^6\;cell/mL$ of initial density in two different artificial wastewaters: one that contained glucose for organic carbon source and the other without carbon source. Nitrate could be successfully reduced below 10 mg $NO_3/mL$ from initial nitrate concentration of 560 mg $NO_3/mL$ in 10 days even in the wastewater without carbon source, This 98% removal of nitrate without extra organic carbon source lights up the future of biological wastewater treatment, where the insufficient ability of nitrogen removal is a major problem.

• 한국물환경학회지
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• 제22권4호
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• pp.711-719
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• 2006

The effluent from anaerobic digestion process of slurry-type piggery waste has a characteristic of very low C/N ratio. Because of high nitrogen content, it is necessary to evaluate nitrogen removal alternative rather than conventional nitrification-denitrification scheme. In this study, two parallel treatment schemes of SBR-like partial nitritation reactor coupled with anaerobic ammonium oxidation (ANAMMOX) reactor, and a nitritation reactor followed by nitrite denitrification process were evaluated with a slurry-type piggery waste. The feed to reactors adjusted with various $NH_4-N$ and organics concentration. The nitrite accumulation was successfully accomplished at the loading rate of about $1.0kgNH_4-N/m^3-day$. The $NO_2-N/NH_4-N$ ratio 1~2.6 in nitritated effluent that operated at HRT of 1 day indicated that SBR-like partial nitritation was applicable to ANAMMOX operation. Meanwhile, the nitrite accumulation of 87% was achieved at SBR operated with HRT of 3 days and $0.4mgO_2/L$ for denitritation. Experimental results further suggested that HRT (SRT) and free ammonia(FA) rather than DO are an effective control parameter for nitrite accumulation in piggery waste.

• 대한환경공학회지
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• 제22권2호
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• pp.231-239
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• 2000

본 연구는 $A_2O$ 공정을 적용한 고정생물막법을 이용하여 고농도의 총무기성질소(TIN) 유입으로 인해 C/N비가 낮은 폐수를 처리하기 위하여 최적의 운전조건 탐색과 생물학적 호기탈질을 평가하였다. 혐기조와 무산소조에 세라믹 여재를 그리고 호기조에 PVC 여재를 충전한 실험장치는 C/N(TOC/TIN)비를 0.5로 일정하게 유지하고 알칼리도를 변화시켜 실험을 실시하였으며 그 결과는 다음과 같다. 유기물제거는 운전조건에 관계없이 96.0% 이상의 높은 제거효율을 얻었다. 유입수의 알칼리도를 약 1210mg/L(Run 5)로 운전하였을 때, $NH_4{^+}-N$와 총 질소 평균 제거효율은 각각 93.5%, 81.8%이었으며, 제거된 총 질소 중 64.9%가 호기조에서 생물학적 탈질에 의해서 제거되었다. 호기조에서 물질수지를 이용하여 질소와 알칼리도를 분석한 결과, 1mg의 $NO_2{^-}-N$가 탈질에 의해 제거될 때 2.49~3.46mg의 알칼리도가 생성되었다. 호기조에서의 생물학적 탈질은 ${\Delta}TOC/{\Delta}DEN$의 이론적인 비 1.22보다 낮은 0.84(Run 5)에서 일어났다.

• Environmental Engineering Research
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• 제16권4호
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• pp.213-218
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• 2011

The two-stage intermittent aeration activated sludge process (IAP) and dynamic-flow intermittent aeration activated sludge process (DFP) were investigated for the nutrient removal of domestic wastewater. Three sets of IAP and one set of DFP were operated. The fermented settled sludge taken from the primary settling tank was added to two IAP and one DFP as an external electron donor, with one IAP, in which an external carbon source was not added, as a control. All the systems were operated at a sludge retention time of 20 days and a hydraulic retention time of 12 hr. A Higher denitrification rate was observed with the fermented settled sludge for the denitrification compared to the process without the addition of the organic source. The result indicates that the fermented acid from the primary domestic sludge has been proved to be an excellent electron donor for denitrification and biological phosphorus removal with IAP and DFP in treating relatively low C/N ratio(Carbon / Nitrogen ratio) wastewater. Phosphate accumulating organisms have a capability of competing with denitrifiers in the presence of volatile organic acids under anoxic conditions.

• Environmental Engineering Research
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• 제10권5호
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• pp.213-226
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• 2005

To treat wastewater efficiently by a one-step process of nitrogen removal, a new bacterial strain producing $N_2$ gas from ${NH_4}^+$ under an aerobic condition was isolated and identified. The cell was motile and a Gram-negative rod, and usually occurred in pairs. By 16S-rDNA analysis, the isolated strain was identified as Enterobacter asburiae with 96% similarity. The isolate showed that the capacity of $N_2$ production under an oxic condition was approximately three times higher than that under an anoxic condition. Thus, the consumption of ${NH_4}^+$ by the isolate was significantly different in the metabolism of $N_2$ production under the two different environmental conditions. The optimal conditions of the immobilized isolate for $N_2$ production were found to be pH 7.0, $30^{\circ}C$ and C/N ratio 5, respectively. Under all the optimum reaction conditions, $N_2$ production by the immobilized isolate resulted in reduction of ORP with both the consumption of DO and the drop of pH. The removal efficiencies of $COD_{Cr}$, and TN were 56.1 and 60.9%, respectively. The removal rates of $COD_{Cr}$, and TN were the highest for the first 2.5 hrs with the removal $COD_{Cr}/TN$ ratios of 32.1, and afterwards the rates decreased as reaction proceeded. For application of the immobilized isolate to a practical process of ammonium removal, a continuous operation was executed with a synthetic medium of a low C/N ratio. The continuous bioreactor system exhibited a satisfactory performance at 12.1 hrs of HRT, in which the effluent concentrations of ${NH_4}^+$-N was measured to be 15.4 mg/L with its removal efficiency of 56.0%. The maximum removal rate of ${NH_4}^+$-N reached 1.6 mg ${NH_4}^+$-N/L/hr at 12.1 hrs of HRT(with N loading rate of $0.08\;Kg-N/m^3$-carrier/d). As a result, the application of the immobilized isolate appears a viable alternative to the nitrification-denitrification processes.

• 한국물환경학회지
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• 제28권6호
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• pp.896-901
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• 2012

축사지역은 가축분뇨처리장으로부터의 오염물질 배출농도가 높아 인근 하천의 수질 및 수생태계에 큰 영향을 끼친다. 또한 강우시에는 축사주위에 축적되어 있던 각종 비점오염물질들이 강우유출수와 함께 유출되어 처리장 방류수와 함께 인근 하천의 주요 오염원으로 작용한다. 그러나 점오염원으로 배출되는 처리장의 배출수와 비점오염원 형태로 배출되는 강우유출수의 오염물질 유출특성이 달라 관리에 어려움을 겪고 있다. 본 연구에서는 축사지역의 점및 비점오염원의 특성을 분석하여 향후 가축분뇨 관리대책 수립에 필요한 기본자료를 제공하고자 한다. 연구대상지역은 10ha의 돈사 지역이며 모니터링은 2008년 10월부터 2011년 11월까지 3년동안 수행되었다. 입자상 물질 및 인의 배출농도는 비점오염원에서 높게 나타났으며, 유기물질 및 질소의 배출농도는 점오염원에서 높게 나타났다. 또한 비점오염원이 섞인 유출수에서는 TN/TP 비에 비해 낮은 BOD 농도를 보였다. 축사지역의 가축분뇨관리는 비점오염원에서의 입자상 물질 관리와 유기물질에 비해 높게 배출되는 점오염원의 영양염류 관리가 필요한 것으로 나타났다.

• 환경위생공학
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• 제20권2호
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• pp.12-20
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• 2005

Most of sewage treatment plants in Korea is operated for the removal of organic material. Because of low C/N ratio of domestic wastewater it is very difficult to remove nitrogen and phosphorus from wastewater. Therefore C/N ratio is key factor for the removed of nitrogen and phosphorus. PSB(photosynthetic bacteria) can remove the nutrient materials, so this study is focused on PSB characterization of nutrient removal. PSB is possible to remove nitrogen, phosphorus in anaerobic and aerobic condition. This study try to find out condition of the PSB in SBR reactor, Batch reactor. It consists of three Mode. Mode 1, 2 is to apply activated sludge process and Mode 3 is that seeded PSB in the activated sludge process. As a result of SBR process, Mode 1, 2 which was activated sludge Process showed $79\~90\%,\;66\~90\%$ of SCODcr, $94.67\~95.89\%,\;95.76\~98.56\%$ of TKN, and Mode 3 has $84\~92\%$ of SCODcr, $95.39\~99.52\%$ of TKN removal efficiency, respectively. When comparison with Mode 1, 2 and 3, most of nitrogen and phosphorus is removed at the anaerobic condition in Mode 3. but Mode 1, 2 has just revealed activated sludge process characterization. It would because of characterization of PSB.

• 한국물환경학회지
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• 제20권1호
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• pp.18-23
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• 2004

In this research, a 2-stage intermittently aerated activated sludge system(IA) and intermittently aerated dynamic flow activated sludge system(DF) were investigated for the removal of nutrients in domestic wastewater. Wastewater was characterized by low C/N( organics/nitrogen) ratio. $COD_{cr}$, $BOD_s$, TKN and TP concentrations of domestic wastewater were 235, 47, 32 and 5.4 mg/L, respectively. Three sets of IA and one set of DF were operated. Three of four systems were added with fermented settled sludge taken from primary settling tank as an external electron donor and the other(IA) for control reactor was operated without addition of electron donor. All systems were operated at same sludge retention time of 20 days and hydraulic retention time of 12hrs. The supplemental electron donor was supplied into the anoxic mode. A higher denitrification rate was observed from the reactors with fermented settled sludge as an electron donor for denitrification compared to that of without addition of organic source. The result of this study indicates that the settled primary sludge, if the fermented at the acid stage, was an excellent electron donor for denitrification. 81 % of TN and 80% of TP were removed from the systems with the supplemental organic source added. However, the control reactor without addition of electron donor showed only 39% of TN and 43% of TP.