• KSBB Journal
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• 제16권2호
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• pp.140-145
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• 2001

To treat piggery wastewater containing refractory compounds including nitrogen, physical treatments using zeolite and biological processes were investigated. In biogical treatment, the removal efficiencies of organics and nitrogen in bioreador using BACC (Biological Activated Carbon Cartridge) media filled with granule activated carbon were examined. The best removal efficiencies achieved for TKN and COD(sub)cr were 82% and 53% respectively, when zeolite dosage was 300 g/L. Specific nitrogen removal ability was 3.2 mg/g at a zeolite dosage of 50 g/L, whereas specific nitrogen removal ability was 1.8 mg/g at a zeolite dosage of 300 g/L. The increased of C/N ratio resulting from the removal of nitrogen using zeolite led to an increase in removal efficiency of organics. As C/N ratio was increased to 2.0, 2.44 and 6.58 at a HRT of 48 hours in a BACC bioreactor, removal efficiencies of COD(sub)cr were increased to 53.5%, 57.4% and 80.6%. The removal efficiency of wastewater using a zeolite dosage of 399 g/L was increased by 27.1% compared to that of control treatment.

• 상하수도학회지
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• 제13권2호
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• pp.55-65
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• 1999

AF(anaerobic filter)/BAF(biological aerated filter) system and UASB(upflow anaerobic sludge blanket)/BAF system, of which system effluents were recirculated to the anaerobic reactors in each system, were operated in order to investigate the performance in simultaneous removal of organics and nitrogen in high-strength dairy wastewater. Advanced anaerobic treatment processes of AF and UASB were evaluated on applicability as pre-denitrification reactors, and BAF was also evaluated on the performance in oxidizing the remaining organics and ammonia nitrogen. At system HRTs of 4.0 to 4.5 days and recirculation ratios of one to three, the AF/BAF system could achieve more than 99% of organics removals and 64 to 78% of total nitrogen removals depending upon the recirculation ratio. Although the UASB/BAF system also showed more than 99% of organics removals, total nitrogen removals in the UASB/BAF system were 53 to 66% which are lower than those in the AF/BAF system at the corresponding recirculation ratios. Optimum recirculation ratios considering simultaneous removal of organics and nitrogen and cost-effectiveness, were in the range of two to three. The upflow AF packed with crossflow module media, as a primary treatment of the anaerobic reactor/BAF system, showed better performances in denitrification, SS removals, and gas production than the UASB. Higher loading rate of suspended solids from the UASB increased the backwashing times in the following BAF. Especially, at a recirculation ratio of three in the UASB/BAF system, the increase in head loss due to clogging in the BAF caused frequent backwashing, at least once d day. The BAF showed the high nitrification efficiency of average 99.2% and organics removals more than 90% at organics loading rate less than $1.4KgCOD/m^3/d$ and $COD/NH_3-N$ ratio less than 6.4. It was proved that the simplified anaerobic reactor/BAF system could maximize the organics removal and achieve high nitrogen removal efficiencies through recirculation of system effluents to the anaerobic reactor. The AF/BAF system can, especially, be a cost effective and competitive alternative for the simultaneous removal of organics ana nitrogen from wastewaters.

• 한국환경과학회지
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• 제11권12호
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• pp.1261-1265
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• 2002

This study was focused on the investigation of the characteristics of organics and nitrogen removal with the recycle ratio in anoxic/oxic(A/O) packed bed process that consisted of the anoxic reactor and the aerobic reactor. As increasing the recycle ratio by 0.5, 1.0, 2.0, the COD removal efficiency increased by 94.0%, 98.5%, 98.8% respectively. The aerobic reactor showed the perfect nitrification efficiency by 98.5%, 99.2%, 98.0% respectively. The T-N removal efficiency with the recycle ratio, increased by 56%, 67%, 70% respectively. As increasing the recycle ratio by 0.5, 1.0, 2.0, T-P removal efficiency decreased by 62.1%, 57.4%, 51.3% respectively. The process by releasing the stored phosphorus in the anoxic reactor and uptaking the excess phosphorus in the aerobic reactor, occurred well comparatively when recycle ratio is 0.5. But this process did not occur when the recycle ratio is 1.0 and 2.0. And optimum pH of nitrification was about 6~7 and alkalinity decreased as nitrification rate increased. As increasing the recycle ratio in the anoxic reactor, DO concentration and ORP increased.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.175.1-175.1
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• 2011

A rotating activated bacillus contactor (RABC) process with a series of aerobic reactors was tested in pilot scale to treat digested liquid from an anaerobic digester treating swine wastewater and sewage sludge. The influent (digested liquid) for the RABC process showed C/N ratios less than 2 as a typical feature of effluent from anaerobic digesters. The pilot process, which consists of three 3 RABC reactors, four aerobic tanks and a sedimentation tank, was operated for 210 days with a hydraulic retention time of 20 days without pH and temperature control. Since the Bacillus-enriched aerobic reactors shows high efficiencies of nitrogen removal at low DO levels less than 1.0 mg/L, they were operated at reduced aeration intensities. With relatively low concentrations of organics in comparison with nitrogen concentrations, the RABC process tested in this study showed stable and high nitrogen and organics removal efficiencies over 80%. The nitrogen removal process tested in this study was proven to be an effective and operation-cost saving (lower aeration) method to remove nitrogen without adding external carbon sources to meet the optimum C/N ratio.

• 한국물환경학회지
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• 제28권3호
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• pp.479-482
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• 2012

Membrane process has been one of the widely applied wastewater treatment options, especially in field. However, one of the tricky issues in the process is to treat concentrates generated from reverse osmosis (RO) system in a manner of saving cost with maximum efficiency for treating a wide range of contaminants. Stimulated with the challenging issues, we have conducted a series of experimental studies in the evaluation for removing organics and nutrients using activated carbon. Results indicated that while powdered activated carbon (PAC) efficiently removed organics and the extent of removal was proportional to the PAC dosage, little removal of nitrogen and phosphorus was observed despite increasing the PAC dose. Interestingly, applying PAC was superior in removing organics than using granular activated carbon (GAC). These results suggest smaller particle size with higher surface area could provide greater chemical reactivity in removing organics.

• 한국환경보건학회지
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• 제29권3호
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• pp.59-64
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• 2003

This study was conducted to investigate anoxic-RBC-anoxic-RBC process and its application to remove biologically organics and nitrogen. BOD and total-nitrogen(T-N) removal efficiencies were decreased as volumetric loading rate increased. But, the removal efficiency changes of T-N were little, as compared to BOD. Increase of internal recycle rate had few affect of BOD and T-N removal rates. Also, influent allocation(to 2nd anoxic reactor) had few affect of BOD removal efficiency rate. However, when the influent allocation rate was 30%, T-N removal efficiency was increased to 84.1 %. BOD/N ratio applied to 2nd anoxic reactor was increased to range of 3.65-4.37 as influent allocation rate increased to range 20∼35%. But, it might also cause adverse effect such as decrease of denitrification rate in excessive influent allocation rate.

• 유기물자원화
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• 제13권4호
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• pp.136-147
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• 2005

난분해성 유기물과 암모니아성 질소의 동시제거를 위해 간헐폭기 생물활성탄 유동상법을 이용하여 고농도 유기물함유 침출수에 대하여 실험을 수행하였다. 간헐폭기시 고려되어야 하는 폭기 시간과 비폭기 시간에 대하여 실험적 검토를 수행하였고 자동컴퓨터제어 가능성에 대하여 고찰하여 보았다. 그 결과 생물활성탄 유동상 반응조에 충전한 활성탄의 물리적 흡착능은 초기의 처리효율에 크게 기여하였으며 간헐폭기 생물활성탄 유동상에 의한 침출수 처리시 정상상태에 도달하는 시간은 40일 정도이었고 TOC와 암모니아성 질소 처리시 양호한 프로세스임을 알 수 있었다. 폭기 및 비폭기시간은 60분 폭기/60분 비폭기의 조건이 30분 폭기/90분 비폭기에 비해 처리효율이 양호하게 나타났고 고농도 유기물함유 침출수 처리실험에서 간헐폭기 생물활성탄 유동상에 의한 처리방법은 높은 TOC제거율, 질산화율 및 탈질율, 난분해성 유기탄소 제거율을 확인할 수 있었다. 또한 간헐폭기시 ORP 곡선의 변화에서 나타나는 굴곡점은 무산소상태의 종결점을 나타내는 파라메터로 이용가능하며 이를 간헐폭기 반응조의 최적 운전모드를 설정하는데 응용할 경우 소규모 자동화가 가능할 것으로 판단되었다.

• 상하수도학회지
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• 제27권6호
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• pp.815-826
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• 2013

Using a developed mathematical model and calibrated kinetic constants, numerical experiments for a aerobic digestion of wastewater sludge by SBR aerobic digestion process combined with ultrasonication (USSBR) were performed in this study. It simulated well the phenomena of the decomposition of particulate organics and the release of organic nitrogen and transformation. To achieve 40 % of particulate organics removal, USSBR process requires only 6 days of SRT and 14 W/L of ultrasonic power whereas SBR aerobic digestion process requires 12 days of SRT. Based on the model simulation results, an empirical equation was presented here. This equation will be used to predict digestion efficiency for the given variables of SRT and ultrasonic power dose. USSBR aerobic digestion process can reduce the nitrogen concentration. The optimal operation strategy for the simultaneous removal of solids and soluble nitrogen in this process is estimated to 7 days of SRT with 14 W/L of ultrasonic power dose while anoxic period was 6 hours out of 24 hours of cycle time. In this condition, 40 % of particulate organics as well as 36 % of total nitrogen will be removed and the soluble nitrogen concentration of the centrate will be lower less then 40 mg/L.

• 상하수도학회지
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• 제13권3호
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• pp.29-35
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• 1999

The purpose of this study is to remove the organics, nitrogen and phosphorus using biosorption for the domestic sewage. The new process using biosorption is based on the methods of contact-stabilization, which remove the organics by absorbing them to the surface of the microorganism in the activated sludge. This process consists of biosorption reactor, biosorption clarifier, nitrifying reactor, nitrifying clarifier, denitrifying reactor, phosphorus uptake(polishing) reactor and final clarifier. The efficiency of removal could be reached 91% for organics, 76% for nitrogen, 90% for phosphorus in Eujungbu pilot plant. We operated the plant which irrigated $10m^3$ per day for sewage. During our operation the HRT(Hydraulic Retention time) was maintained for 10.5hr, but it could be reduced as 8.5hr according to our operation results.

• 한국물환경학회지
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• 제31권5호
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• pp.556-562
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• 2015

In order to remove the organic substances and the nitrate-nitrogen contained in wastewater, some researchers have studied the simultaneous removal of organics and nitrogen by using different biocathode microbial fuel cells (MFCs). The operating conditions for removing the contaminants in the MFCs are the external resistances, HRTs, the concentration of the influent wastewater, and other factors. This study aimed to determine the effect of the external resistors and organic loading rates, from the changing HRT, on the removal of the organics and nitrogen and on the production of electric power using the Denitrification Biocathode - Microbial Fuel Cell (DNB-MFC). As regards the results of the study, the removal efficiencies of $SCOD_{Cr}$ did not show any difference, but the nitrate-nitrogen removal efficiencies were increased by decreasing the external resistance. The maximum denitrification rate achieved was $129.2{\pm}13.54g\;NO_3{^-}-N/m^3/d$ in the external resistance $1{\Omega}$, and the maximum power density was $3,279mW/m^3$ in $10{\Omega}$. When the DNB-MFC was operated with increasing influent organic and nitrate loading by reducing the HRTs, the $NO_3{^-}-N$ removal efficiencies were increased linearly, and the maximum nitrate removal rate was $1,586g\;NO^3{^-}-N/m^3/d$ at HRT 0.6 h.