The growth characteristics of Commercially Developed Nitrifying Bacteria (CDNB) were studied in laboratoryscale. CDNB, a pure, artificially isolated bacterium, was cultivated to produce Cultivated Nitrifying Bacterium Group (CNBG). The average ammonia removal rate of CDNB was 0.0234g $NH_4^+-N/g$ MLSS/hr. CNBG was produced in the batch reactor and Specific Nitrification Rate (SNR) was determined at 0.0107g $NH_4^+-N/g$ MLSS/hr. The SNR of CNBG was lower than the SNR of CDNB because the diverse and multi-cultured microbial growth took place during cultivation. The effect of the temperatures and the mixing ratios of sewage and culture solution on the SNR of CNBG was studied. The SNR of CNBG, 0.0107g $NH_4^+-N/g$ MLSS/hr at $27^{\circ}C$, decreased to 0.0048g $NH_4^+-N/g$ MLSS/hr at $15^{\circ}C$, and temperature coefficient (${\Theta}$) was calculated to be 1.07. With the varied sewage mixing ratios, the SNR of CNBG remained unchanged. Activated sludge reactors maintaining an MLSS of 2,000mg/L at HRT of 4 h were operated under conditions in which dosage of Concentrated CNBG Solution (CCNBGS, 10,000mg MLSS/L) and application method of CNBG were varied. The reactor with 20mL of CCNBGS took shorter time to oxidize $NH_4^+-N$ reaching 1mg/L than the reactor with 5mL of CCNBGS showing that higher dosages were associated with greater mass removal of $NH_4^+-N$. However, the total removal was not great. In terms of different methods of CNBG application, reactor seeded with 20mL of CCNBGS took 3days to reach 1mg/L of effluent ammonia concentration while reactor dosed with 20% (v/v) CNBG implanted media took 2days. Both the control reactor and the reactor dosed with 20% (v/v) media only did not reach 1mg $NH_4^+-N/L$ after operating 18days. The reactor with CNBG implanted media had the highest $NH_4^+-N$ removal rate because of maintaining high concentration of Nitrifying Oxidizing Bacteria (NOM), and is regarded as an appropriate method for the activated sludge process.
Journal of Korean Society of Environmental Engineers
/
v.33
no.2
/
pp.120-131
/
2011
A pilot-scale experiment of floodplain filtration with a filtration depth of 3.6m was performed employing flood/rest type raw-water supply system in an effort to find ways to improve river water quality by additional treatments of discharged effluent from sewage treatment plant. Soil samples were taken from 3 sites including Gumi, Daegu and Gimhae along the Nakdong river. Reductions of infiltration rates following increases in operating time was investigated in each soil sample, along with the analysis of removal efficiencies of various pollutants according to different depths and infiltration rates. The results show incremental development of clogging on the soil surface with increases in operation time, and illustrate exponential decrease in the infiltration rate. The time required for the removal of the clog from the soil surface was longer than 2 weeks for all soil samples analyzed. The stable infiltration rates for soils were 5 m/day for Gumi and for Daegu and Gimhae was 1 m/day. In unsaturated soils dissolved oxygen levels increased following the increase of filtration depth, suggesting that alternating application of flood and rest for raw-water supply effectively keeps the soil environment aerobic. For all soils, the nature of pollutant removal depending on the depth of filtration remained the same regardless of the infiltration rate. Most of the BOD and turbidity were removed within 1.2 m, about 30% of COD was removed within 3.6m and was expected to be removed further with increases in filtration depth. Nitrification occurred near the surface of all soils; however there was no significant removal of nitrogen in the filtration depths tested in this study. Although removal rate of phosphorus was low for Gumi's soil, it was high enough for other soils, suggesting that the method developed in this study could significantly improve river water quality.
Journal of Korean Society of Environmental Engineers
/
v.33
no.2
/
pp.113-119
/
2011
The study purpose was to examine an effect of zero emission of excess sludge on biological reactor and treated water quality within the biological reactor in the process of biological treatment combined with excess sludge reduction system with ozone. Under an ozone injection rate 0.03 g $O_3/g$ SS, Sludge Disintegration Number (SDN) 3 and less than pH 4 as pre-treatment process, it was possible to maintain a stable biological treatment process without sludge disintegration. In the test of $OUR_{max}$, of sludge, its value was hardly under the condition of ozone injection rate 0.03 g $O_3/g$ SS. There were almost no changes of MLVSS/MLSS within biological reactor followed by a solubilization of excess sludge. Accumulation of microorganism within biological reactor was also not observed. After solubilization of excess sludge, an increase for organic matter and SS concentrations of an effluent was not observed and T-N concentration was reduced by increasing nitrification and denitrification rate within biological reactor. Most of T-P was not removed by zero emission of excess sludge and was leaked by being included in effluents.
An aerobic submerged membrane bioreactor (MBR) treating ammonium wastewater was studied in respect of nitrification characteristics and distribution of nitrification bacteria over a period of 350 days. MBR was fed with ammonium concentration of 500-1000 mg $NH_4-N/L$ at a nitrogen load of $1-2kg\;N/m^3{\cdot}d$. Overall ammonium oxidation rate increased with dissolved oxygen (DO) concentration, temperature, and sludge retention time (SRT). Under a higher concentration of free ammonia ($NH_3-N$) due to the decrease of ammonium oxidation rate, the nitrite ratio ($NO_2-N/NO_x-N$) in the effluent increased. The sudden collapse of nitrification efficiency accompanied by sludge foaming and the increase of sludge volume index (SVI) was observed unexpectedly during the operation. At the later stage of operation, additional carbon source was fed to the MBR and resulted in twice higher value of SVI and the decrease of ammonium oxidation rate. In fluorescence in situ hybridization (FISH) analysis, genus Nitrosomonas which is specifically hybridized with probe NSM156 was initially the dominant ammonia oxidizing bacteria and the amount of Nitrosospira gradually increased. Nitrospira was the dominant nitrite oxidizing bacteria during whole operational period. Significant amount of Nitrobacter was also detected which might due to the high concentration of nitrite maintained in the reactor.
The generation of high-purity hydrogen from hydrocarbon fuels is essential for efficient operation of fuel cell. In general, most feasible strategies to generate hydrogen from hydrocarbon fuels consist of a reforming step to generate a mixture of $H_2$, CO, $CO_2$ and $H_2O$ (steam) followed by water gas shift (WGS) and CO clean-up steps. The WGS reaction that shifts CO to $CO_2$ and simultaneously produces another mole of $H_2$ was carried out in a two-stage catalytic conversion process involving a high temperature shift (HTS) and a low temperature shift (LTS). In a typical operation, gas emerges from the reformer is taken through a high temperature shift catalyst to reduce the CO concentration to about 3~5%. The HTS reactor was designed and tested in this study to produce hydrogen-rich gas with CO to a range of 2~4%. The iron based catalysts (G-3C) was used for the HTS to convert the most of CO in the effluent from the partial oxidation (POX) to $H_2$ and $CO_2$ at a relatively high rate. Parametric screening studies were carried out for variations of the following variables: reaction temperature, steam flow rate, components ratio ($H_2/CO$), and reforming gas flow rate.
Journal of the Korea Organic Resources Recycling Association
/
v.16
no.4
/
pp.91-97
/
2008
The objective of this research is to investigate the effect of the addition of granular activated carbon (GAC) and granular sludge on the performance of upflow anaerobic sludge blanket (UASB) reactors for treating leachate. For the control reactor, sludge obtained from an anaerobic digester was used as a seed material. On the other hand, GAC and granular sludge were incorporated with the seed sludge in the GAC reactor and the Granule reactor, respectively. The shortest acclimation period was observed in the Granule reactor. The GAC reactor also gave comparable performance to the Granule reactor at the beginning of operation. However, as the adsorptive capacity of GAC was exhausted, the effluent COD concentration increased gradually. Once the systems were stabilized, the GAC reactor showed slightly better results than the other two reactors in terms of chemical oxygen demand (COD) removal. COD removal in all reactors was more than 90% at hydraulic retention time of 1.0 day. Furthermore, GAC reactor showed little variation in COD removal rate and remained at 95% with organic loading rate (OLR) of 4.0 to $8.2kg\;COD/m^3.d$. Initial operating period was reduced by the addition of granular sludge, while the treatment efficiency was enhanced by the addition of GAC.
Recycled packed-bed reactor emploring immobilized microorganism was suggested in this paper for efficient denitrification. In the batch reactor, the effects of initial oxidation-reduction potential and nitrate concentration on denitrification were investigated. As the initial oxidation-reduction potential was decresed to -70 mV from +40 mV, the removal rate of nitrate was increased to 3.33 from 1.25 m9 NO$_3$$\^$-/-N/min under the experimental conditions. As the initial nitrate-N concentraion was increased to 200 mg/l, the removal rate of nitrate was proportional to the concentration of nitrate. When the concentration of nitrate-N was 400 mg/min, nitrite was detected, and when the initial nitrate-N concentration was reached at 1,000 mg/l, it took longer time for the complete nitrate removal. In order to decrease the initial oxidation-reduction potential and the nitrate-N concentration in the feed stream, the effluent was recycled to the influent stream in the packed-bed reactor. In the case of recycling, the initial oxidation-reduction potential was decreased to 30 mV from 150 mV, and the initial nitrate concentration could be decreased to 85 from 120 mg NO$_3$$\^$-/-N/l. As the result of recycling, the removal rate of nitrate was increased to 91.7% from 49.2%.
Journal of the Korean Society for Marine Environment & Energy
/
v.6
no.1
/
pp.11-20
/
2003
The pollution loads flowing into Mokpo harbour from land in dry case were estimated on the bases of the seasonal flow rates and the seasonal water qualities of streams and effluents located around Mokpo harbour. Average daily amount of fresh water Stowing into Mokpo harbour obtained by the inflow rate data of 4 seasons was found to be about 5.5×10/sup 6/㎥/day and annual inflow rate to be about 2×10/sup 9/㎥/year. The seasonal flow rates of effluents iron Yongsan lake were above 90% of total flow rates of all inflows in 4 seasons. The concentrations of COD, TSS, TIN and TP at 9 inflow stations Iron streams and effluents in 4 seasons were shown to be in the ranges of 2.87~42.69㎎/ℓ, 3.65~1080.32㎎/ℓ, 0.083~89.744㎎/ℓ and 0.028~6.926㎎/ℓ, respectively. The average loads of COD, TSS, TIN and TP into Mokpo harbour estimated by the data of 4 seasons were found to be about 37 ton/day, 64 ton/day, 13 ton/day and 1.2 ton/day, respectively. The loads of COD, TSS, TIN and TP into Mokpo harbour in summer were shown to be about 82 ton/day, 159 ton/day, 14 ton/day and 2 ton/day, respectively. The main source of pollution loads into Mokpo harbour was found to be the effluent of Yongsan lake.
Byungseok Kal;Jaebeom Park;Seongmin Kim;Sangmin Shin;Soonja Jang;Minjae Jeon;Donghyun Lee
Journal of Wetlands Research
/
v.25
no.4
/
pp.326-334
/
2023
The purpose of this study is to use long-term water quality monitoring data from tributaries of the Nakdong River system to identify problematic substances in tributaries by examining the rate of exceedance and increase in water quality targets. In the Nakdong River system, monitoring is conducted once a month for 38 tributaries that require intensive management, and this data was used to analyze trends in exceeding and increasing target water quality at each point. The analysis items are eight items that can be evaluated based on river water quality standards: DO, BOD, COD, TOC, SS, total phosphorus, fecal coliform, and total coliform. As a result of the analysis, the target water quality exceedance rate was more than 50%, and the items with an increasing trend were TOC, fecal coliform and total E. coli counts, and the items with an exceedance rate of less than 50% but an increasing trend were SS. TOC is believed to be caused by an increase in non-degradable substances, and the continued increase in Total Coliform will require management of Total ColiformTotal Coliform in effluent water from sewage treatment facilities in the future.
Improvement of the solid-liquid separation efficiency in the secondary sedimentation tank of the biological treatment process, is known to be increasing effectiveness of the overall system operation. Sewage treatment plant effluent SS is composed of most organic substances. In order to reduce the SS component in the secondary sedimentation tank discharge, fine SS components constituting the heterogeneous should be increased by its own aggregation (self flocculation), so that can be deleted through their precipitation. So, it is improved through using the installation of double rectification wall in this secondary tank. In case, sewage is rapidly increased due to the daily change of the influent water, it was confirmed that suspended solids caused by the impact load are processed stably. Therefore, there is a need for a facility installation which can be its own aggregation for reduction suspended solids in secondary sedimentation tank.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.