Journal of Korean Society of Environmental Engineers
/
v.27
no.5
/
pp.519-524
/
2005
Due to the low C/N ratio of domestic wastewater characteristic, addition of external carbon source for the effective N and P removal is necessary. High organic content of food waste can be used for the external carbon source in biological nutrient removal processes, The applicability of condensate of food waste (CFW), which is produced during the high-rate fermentation process, was examined in membrane bioreactor for the nutrient removal. Under the various operating conditions, nutrient removal efficiencies and membrane fouling characteristics were evaluated using synthetic wastewater. From nitrate utilization rate (NUR) test, denitrification rate was 0.19 g $NO_3-N/g$ VSS/day. With the addition of CFW increased, average removal efficiencies of T-N and T-P could be increased up to 64% and 41%, respectively. Also the optimal retention time was 3 hr/5 hr for anoxic/aerobic reactor. When applied to real sewage, membrane fouling resistance was increased up to 60%, which could be reduced from $10.4{\times}10^{12}m^{-1}$ to $5.9{\times}10^{12}m^{-1}$ with the control of influent suspended solid concentration. In summary, it was suggested that CFW could be used as an economical and effective carbon source for membrane assisted biological N and P removal.
Kim, Ju-Hwan;Bae, Chul-Ho;Kim, Jung-Hyun;Hong, Sung-Ho;Lee, Kyung-Jae
Journal of Korean Society of Water and Wastewater
/
v.20
no.4
/
pp.545-558
/
2006
The current conditions of large water mains are evaluated by deteriorations and the causes of deterioration are investigated through visual assessments in the field, mechanical tests and analysis of chemical compositions in laboratory for each pipe material, unlined cast iron pipes (CIPs), ductile iron pipes (DCIPs) and steel pipes (SPs) Tubercles and scales from internal and external corrosion of unlined cast iron pipes were identified as the causes of functional performance limitations in large water mains. It is investigated that main causes of internal and external corrosion of water pipes are from lots of depositions of organic and inorganic substances on pipe surface, concentrated pitting, and uniform corrosion by local or global exfoliation or detachment of lining and coatings of DCIPs and SPs. Internal and external corrosion depths of CIPs were higher than those of DCIPs and SPs. Consequently, total corrosion rate summed internal and external corrosion rates of CIPs also were shown to be higher than those of DCIPs and SPs. The failure time from hole generation of CIPs by total corrosion rate was predicted to be taken sixteen years, and DCIPs and SPs were twenty-six years and one hundred and fifty three years. And longitudinal deflection of investigated water mains were not happened and mechanical strengths such as tensile strength, elongation, and hardness also were mostly suited to Korea Standards. It was thought that the weakness of tensile strength of one sample(S-11) was, however, due to higher carbon contents(%) in CIPs. Pipe deterioration score of S-46 was 55.2 and was preferentially assessed to be rehabilitated.
Micro-electro-mechanical systems (MEMS) are widely employed in sensors, biomedical devices, optic sectors, and micro-accelerometers. New reinforcement materials such as carbon nanotubes as well as graphene platelets provide stiffer structures with controllable mechanical specifications by changing the graphene platelet features. This paper deals with buckling analyses of functionally graded graphene platelets micro plates with two piezoelectric layers subjected to external applied voltage. Governing equations are based on Kirchhoff plate theory assumptions beside the modified couple stress theory to incorporate the micro scale influences. A uniform temperature change and external electric field are regarded along the micro plate thickness. Moreover, an external in-plane mechanical load is uniformly distributed along the micro plate edges. The Hamilton's principle is employed to extract the governing equations. The material properties of each composite layer reinforced with graphene platelets of the considered micro plate are evaluated by the Halpin-Tsai micromechanical model. The governing equations are solved by the Navier's approach for the case of simply-supported boundary condition. The effects of the external applied voltage, the material length scale parameter, the thickness of the piezoelectric layers, the side, the length and the weight fraction of the graphene platelets as well as the graphene platelets distribution pattern on the critical buckling temperature change and on the critical buckling in-plane load are investigated. The outcomes illustrate the reduction of the thermal buckling strength independent of the graphene platelets distribution pattern while meanwhile the mechanical buckling strength is promoted. Furthermore, a negative voltage, -50 Volt, strengthens the micro plate stability against the thermal buckling occurrence about 9% while a positive voltage, 50 Volt, decreases the critical buckling load about 9% independent of the graphene platelet distribution pattern.
Journal of the Korea Organic Resources Recycling Association
/
v.23
no.4
/
pp.11-20
/
2015
In the present work, a basic study on the in-situ biogenic methane generation from low grade coal bed was conducted. Lignite from Indonesia was used as a sample feedstock. A series of BMP (Biochemical Methane Potential) tests were carried out under the different experimental conditions. Although nutrients and anaerobic digester sludge were added to the coal, the produced amount of methane was limited. Both temperature control and particle size reduction showed little effect on the increase of methane potential. When rice straw was added to lignite as an external carbon source, methane yield of 94.4~110.4 mL/g VS was obtained after 60 days of BMP test. The calorific value of lignite after BMP test decreased (4.5~12.1 %) as increasing the content of rice straw (12.5~50 wt % of lignite), implying that anaerobic digestion of rice straw led to partial degradation of lignite. Therefore, rice straw could be used as an external carbon source for the start-up of in-situ biogas generation from low grade coal bed.
The aim of this research is to derive an optimum operating condition for the thermal solubilization equipment that is employed to increase concentration of soluble organic materials and to assess whether it would be possible to use the waste sludge generated by thermal solubilization reaction as an external carbon source in biological denitrification process. For the purpose, we have constituted a laboratory-size thermal solubilization equipment and have assessed thermal hydrolysis efficiency based on various reaction temperature and reaction time. We have also derived SDNR using the waste sludge generated by thermal solubilization reaction through a batch experiment. As a result of research, the highest thermal hydrolysis efficiency of about 42.8% was achieved at $190^{\circ}C$ of reaction temperature and at 90 minutes of reaction time. And when SDNR was derived using the waste sludge, the value obtained was $0.080{\sim}0.094\;g\;NO_3{^-}-N/g\;MLVSS{\cdot}day$, showing SDNR that is higher than that obtained by the results of existing researches that used common wastewater as an external carbon source. Accordingly, in view of the fact that food wastes vary quite a bit in characteristics based on the area they are generated from and seasonal change, it seems that a flexible operation of thermal solubilization equipment is required through on-going monitoring of food wastes that are imported to food wastes recycling facilities.
This study examined the removal efficiency of the nitrogen and phosphorus in order to compensate for the combined process of ATAD(Autothermal Thermophilic Aaerobic Digestion) and EGSB(Expended Granular Sludge Bed), which are treatment methods for livestock wastewater, by introducing SBR(Sequencing Batch Reactor) as post-treatment process. The analysis on the treatment efficiency of each operation mode showed that, in the case of T-N, the treatment efficiency were 67.1% and 74.2% for Run-1 and Run-2, respectively, and in the case of T-P, the values were 71.2 and 74.1, respectively, which are indicating that the treatment efficacy is higher in the condition of Run-1, in which the time period of Anoxic and Aerobic segments were increased. In addition, the result of analyzing removal characteristics of nitrogen and phosphorus by Influx load showed that removal efficiency of nitrogen was better in the case of high influx load than in the case of low influx load. Regardless of Influx load, phosphorus showed constant influx concentration, so that removal efficiency of phosphorus was influenced littler by Influx load than that of nitrogen. This study also fed methanol as an external carbon source and performed experiment to induce denitrification under anoxic condition by using nitrate among nitrogen compounds of SBR reactor, and the results showed that intermittent feeding was more effective in Nitrogen Removal than composite feeding.
Jin-Young Kang;Young-Ho Jang;Byeong-Hwan Jeong;Yeon-Jin Kim;Yong-Ho Kim
Journal of Korean Society on Water Environment
/
v.39
no.5
/
pp.390-395
/
2023
The feasibility of applying the shortcut nitrogen removal process to treat livestock wastewater on individual farms was examined, and appropriate operating parameters were established. As a result,, it was determined that the nitrification reaction was carried out under 550 mg/L of ammonium nitrogen concentration, but it was less effective under conditions of high ammonia concentration. Consequently, it was confirmed that a partial injection of inflow water was necessary to minimize the effects of ammonia toxicity. Following the sequential batch reactor (SBR) operation results, it was difficult to achieve the effluent quality standard without an external carbon source. Also, selection of the appropriate hydraulic retention time was critical for the optimal SBR operation. Following the livestock farm application, with external carbon source injecting, the total nitrogen concentration in the effluent was 85.1 mg/L. This result revealed that the standard could be accomplished through a single treatment on individual livestock farms. The ratio of nitrite nitrogen to ammonia nitrogen in the effluent was verified to be suitable for implementing the anammox process with a 10 days of hydraulic retention time. This study demonstrated the potential applicability of process in the future. However, in order to apply to livestock farms, managing variations in wastewater load across individual farms and addressing reduced nitrogen oxidation efficiency during the winter season are crucial.
The autochthonous and allochthonous organic carbon loading were measured in Lake Soyang, to estimate the amount of carbon loading into the lake and the contribution of their sources to tile lake's carbon loading. Autochthonous carbon loading was estimated from phytoplankton primary production with the extracellular organic carbon (EOC). Allochthonous loading was determined by measuring dissolved organic carbon (DOC) and particulate organic carbon (POC) concentration in the main inflowing Soyang River. Both autochthonous and allochthonous organic carbon loading were high during the svmmer, from July to September, and accounted for 43.2% and 71.7% of the annual loading, respectively. Primary productivity was elevated up to $1,000\;mgC\;m^{-2}\;d^{-1}$ during summer and lowest in winter. EOC production from phytoplankton was also large in summer, resulting in a high DOC concentration in the lake water. Primary production of phytoplankton and allochthonous organic matter loading from the watershed contributed to 53.6% and 46.4% of total loading, respectively. The EOC production accounted far $4.4{\sim}21.2%$ of POC primary production, implying that EOC production of phytolankton must be considered in estimation of primary production.
This study is examined interaction between carbon market with stock market using a multivariate GARCH(DCC) model. Carbon market is EU ETS EUA price, stock market is the iron and cement stock price which has relatively energy intensive and massive carbon emissions sector in the industrial sector. It also analyzed changes in the correlation between the markets through an analysis of correlation coefficients. Moreover, it checked whether there was marketability expansion(or expansion of carbon emissions reduction) through the analysis above. As a result of empirical tests, it showed that the price spillover effect was insignificant. In addition, it represented that there was a weak correlation between the two markets since the volatility spillover effect disappeared in the second phase by an external shock(a financial crisis). Moreover, it was revealed that there were no significant changes although there was a weak upward trend in terms of the correlation between the carbon market and the stock market. This implies that emission rights could not expand marketability to financial market as a commodity(or did not play its natural role of the reduction of carbon emission).
Vibrio vulnificus needs various responsive mechanisms to survive and transmit successfully in alternative niches of human and marine environments, and to ensure the acquisition of steady energy supply to facilitate such unique life style. The bacterium had genetic constitution very different from that of Escherichia coli regarding metabolism of glycogen, a major energy reserve. V. vulnificus accumulated more glycogen than other bacteria and at various levels according to culture medium and carbon source supplied in excess. Glycogen was accumulated to the highest level in Luria-Bertani (3.08 mg/mg protein) and heart infusion (4.30 mg/mg protein) complex media supplemented with 1% (w/v) maltodextrin at 3 h into the stationary phase. Regarding effect of carbon source, more glycogen was accumulated when maltodextrin (2.34 mg/mg protein) was added than when glucose or maltose (0.78.1-14 mg/mg protein) was added as an excessive carbon source to M9 minimal medium, suggesting that maltodextrin metabolism might affect glycogen metabolism very closely. These results were supported by the analysis using the malP (encoding a maltodextrin phosphorylase) and malQ (encoding a 4-${\alpha}$-glucanotransferase) mutants, which accumulated much less glycogen than wild type when either glucose or maltodextrin was supplied as an excessive carbon source, but at different levels (3.1-80.3% of wild type glycogen). Therefore, multiple pathways for glycogen metabolism were likely to function in V. vulnificus and that responding to maltodextrin might be more efficient in synthesizing glycogen. All of the glycogen samples from 3 V. vulnificus strains under various conditions showed a narrow side chain length distribution with short chains (G4-G6) as major ones. Not only the comparatively large accumulation volume but also the structure of glycogen in V. vulnificus, compared to other bacteria, may explain durability of the bacterium in external environment.
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.