• 상하수도학회지
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• 제17권4호
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• pp.503-509
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• 2003

COD fractionation of primary settled municipal wastewater was conducted by respirometry. RBCOD (Readily Biodegradable COD) fraction was analyzed to be 21% of influent TCOD. However, SCOD fraction, analyzed by physical separation using $0.45{\mu}m$ membrane filter, was about 31% of TCOD. Therefore, 10% of soluble inert COD was comprised in TCOD. It means that kinetic analysis of activated sludge system was impossible because serious error would be occurred if SCOD was used as a biodegradable soluble component instead of RBCOD estimated from respirometry. In this study, RBCOD fraction of raw wastewater could be analyzed by respirometry within the error range of 57%. In addition, SBCOD (Slowly Biodegradable COD) content could be determined by kinetic simulation of the experimental results. SBCOD showed about 2-fold higher fraction (38% of TCOD) as compared with RBCOD.

• 한국토양비료학회지
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• 제46권4호
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• pp.296-302
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• 2013

This study was carried out to investigate the effect of organic content level on ultimate methane potential and anaerobic biodegradability of substrate by biochemical methane potential assay. Three organic matters (whole sludge and liquid and solid fraction of sludge) of the same origin, which had different organic contents, were fermented at the batch anaerobic reactor for 70 days. Ultimate methane potential and anaerobic biodegradability were determined by the terms of volatile solid (VS) and chemical oxygen demand (COD). Volatile solid contents of whole sludge and solid and liquid fraction of sludge were 2.4, 18.8, and 0.2% and COD were 5.3, 30.4, and 0.5%, respectively. Ultimate methane potentials ($B_u$-COD) and anaerobic biodegradability ($D_{VS}$) determined by VS content were $0.5Nm^3kg^{-1}-VS_{added}$, 76.3% for whole sludge, $0.5Nm^3kg^{-1}-VS_{added}$, 76.3% for the liquid fraction of sludge, and $0.6Nm^3kg^{-1}-VS_{added}$, 77.0% for the solid fraction of sludge. Ultimate methane potentials ($B_u$-COD) and anaerobic biodegradability ($D_{COD}$) determined by COD were $0.2Nm^3kg^{-1}-COD_{added}$, 73.4% for whole sludge, $0.2Nm^3kg^{-1}-VS_{added}$, 74.0% for the liquid fraction of sludge, and $0.33Nm^3kg^{-1}-COD_{added}$, 99.1% for the solid fraction of sludge. In conclusion, ultimate methane potential and anaerobic biodegradability given by the VS term showed more reasonable results because COD might be underestimated by the interference of $NH_4{^+}$ in the case of highly concentrated organic material.

• 산업기술연구
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• 제16권
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• pp.51-60
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• 1996

This research was performed for the fundamental data using a advanced treatment process of piggery wastewater. Characteristics of influent wastewater was divided with various methods in fixed biofilm batch reasctor. Fractons of organic were divided into readily biodegradable soluble COD(Ss), slowly biodegradable COD(Xs), nonbiodegradable soluble COD($S_I$), and nonbiodegradable suspended COD($X_I$). Experimental results were summerized as following : i) biodegradable organics fraction in piggery wastewater was about 88.1 percent, and fraction of readily biodegradable soluble COD was about 66.1 percent. ii) Fractions of nonbiodegradable soluble COD was 11~12 percent, and soluble inert COD by metabolism was producted about 6~8 percent. iii) Active biomass fraction of attached biofilm was about 54.7 percent, and substrate utilization rate and maximum specific growth rate of heterotrophs were $8.315d^{-1}$ and $3.823d^{-1}$, respectively.

• 상하수도학회지
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• 제21권5호
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• pp.513-520
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• 2007

The simulation programs used for diagnosis and design of activated sludge process require organic fractions in municipal wastewater as the input variables. However, methods for characterizing organic fractions are still under development, and are not standardized. In this study, total COD of municipal wastewater was experimentally subdivided into readily and slowly biodegradable COD as well as soluble and particulate inert COD. The COD fractionation of the three municipal wastewater for one year shows linear relationship between each COD fraction and TCOD concentration with around 100% COD balance. This result means that the COD fraction do not vary very much with time, although the actual influent concentrations vary significantly with time and day. Therefore, the experimentally subdivided COD fractions can be utilized as wastewater specific parameters for the simulation of activated sludge processes.

• 한국물환경학회지
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• 제23권3호
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• pp.309-313
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• 2007

In Activated Sludge Model, COD fraction of primary settled municipal wastewater was a very important parameter. In this study, the COD fraction was determined using the oxygen utilization rate experiments. Readily biodegradable COD ($S_S$) fraction was observed about 29.7% of influent TCOD. $S_I$, $X_I$, and $X_S$ were analyzed to be 7.6%, 7.3%, and 55.4% of TCOD, respectively. The model used in this study was developed based on ASM3 and modified Bio-P module in order to simulate the existing BNR process. Parameter estimation results showed that $Y_{STO,O2}$, $Y_{STO,NO}$, $Y_{H,O2}$, $Y_{H,NO}$, $Y_{PO4}$, ${\mu}_H$, $b_H$, ${\mu}_A$, $q_{PHA}$, $q_{PP}$ and ${\mu}_{PAO}$ were 0.7, 0.64, 0.61, 0.48, 0.31, 3.9, 0.1, 1.35, 4.98, 1.8 and 0.59, respectively. Using the presented model and the estimated parameters, the simulation of the existing BNR process was successfully conducted.

• Environmental Engineering Research
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• 제10권1호
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• pp.7-14
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• 2005

The feasibility of hydrogen production with a raw seed sludge through direct acclimation of feedstock was investigated at acidogenic stage, and methane was harvested at followed methanogenic stage in an anaerobic two-stage process. Hydrogen content was higher than 57% at all tested organic loading rates (OLRs) and the yield of hydrogen ranged from 1.5 to 2.4 mol H2/mol hexose consumed and peaked at 6 gVSl-1day-1. Normal butyrate and acetate were main volatile fatty acids (VFAs), whereas the concentration of propionate was insignificant. The hydrogen-producing bacteria, Clostridium thermosaccharolyticum, was detected with strong intensity at all tested organic loading rates (OLRs) by denaturing gradient gel electrophoresis (DGGE) of the polymerase chain reaction (PCR) analysis. From COD balance in the process, the fraction of the feed-COD converted to the hydrogen-COD at acidogenic stage ranged from 7.9% to 9.3% and peaked at 6 gVSl-1day-1, whereas the fraction of feed-COD converted to the methane-COD at methanogenic stage ranged from 66.2% to 72.3% and peaked at 3 gVSl-1day-1.

• 한국지반환경공학회 논문집
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• 제5권4호
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• pp.25-31
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• 2004

일반 활성슬러지 공정에서 유입수의 COD 분율은 매우 중요한 인자이다. 강화된 수질기준의 준수를 위해서는 유입수내 COD 분율화에 기초한 활성슬러지 공정의 주요 운영조건 변화가 요구된다. 본 연구에서는 이분해성 COD와 천천히 분해되는 COD의 대표 구성물질로써 글루코스와 펩톤을 이용하여 기지농도의 합성폐수를 조제하였으며, 산소이용율(OUR)과 질산성질소 이용율(NUR)을 이용하여 기지의 농도로 제조된 합성폐수에 대해 기존 COD 분율화 방법활용시 결과예측의 정확성 검증과 평가에 관한 실험을 수행하였다. OUR 실험의 경우, 기지의 농도로 제조된 합성폐수와 일치되는 결과를 얻을 수 있었으나 NUR 실험의 경우, 유입수 분율화에 오차가 발생하는 것으로 나타났다. 이와 같은 오차는 인축적 미생물(PAOs)와 같은 저장 미생물의 내부저장기작에 의한 결과로써 유입수 분율화에 최대 8-14 %의 오차를 유발하는 것으로 나타났다.

• 상하수도학회지
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• 제21권5호
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• pp.551-558
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• 2007

From the view point of biological wastewater treatment, C/N ratio is one of the most important factor in biological nutrient removal process. However, municipal sewage in Korea is characterized by extremely low content of carbon source and relatively higher portion of N source. Accordingly, it is necessary to dose external carbon source in order to obtain higher degree of carbon source within the process. In this study, the effects of pH pretreatment as an alternative plan for increasing carbon source on the cell disruption and COD solubility of waste activated sludge were conducted under well defined experimental conditions. During 5 hours, the value of COD solubilization rate ($S_R$) at pH 11.5 is approximately 4.4 times higher than the value of $S_R$ at pH 9.5. It is expected that the level of SCOD increased due to the result from cell disruption. However, VSS/TSS ratio was not significantly changed after 5 hours. As Alkalinity changes gradually from less than 15, 30 and 60 meq NaOH/L, average RBCOD/SCOD fraction showed 34, 36 and 45%,respectively.

• Membrane and Water Treatment
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• 제9권3호
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• pp.155-162
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• 2018

Process modeling with activated sludge models (ASMs) is useful for the design and operational improvement of biological nutrient removal (BNR) processes. Effective utilization of ASMs requires the influent fraction analysis (IFA) of the wastewater treatment plant (WWTP). However, this is difficult due to the time and cost involved in the design and operation steps, thereby declining the simulation reliability. Harmony Search (HS) algorithm was utilized herein to determine the relationships between composite variables and state variables of the model IWA ASM1. Influent fraction analysis was used in estimating fractions of the state variables of the WWTP influent and its application to 9 wastewater treatment processes in South Korea. The results of influent $S_s$ and $Xs+X_{BH}$, which are the most sensitive variables for design of activated sludge process, are estimated within the error ranges of 8.9-14.2% and 3.8-6.4%, respectively. Utilizing the chemical oxygen demand (COD) fraction analysis for influent wastewater, it was possible to predict the concentrations of treated organic matter and nitrogen in 9 full scale BNR processes with high accuracy. In addition, the results of daily influent fraction analysis (D-IFA) method were superior to those of the constant influent fraction analysis (C-IFA) method.

• 한국환경과학회지
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• 제6권6호
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• pp.589-594
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• 1997

A total of 24 surface sediment samples collected from coastal region and fronting of sea cliff on Cape Cod In southeastern Massachusetts, were analyzed to Investigate the sediment transport mechanism. According to the result of grainsize analysis, the overall trend of g.k size decreases from the north(Wood End Beach) to the south(Nauset Light Beachy. The coarser materials tend to be deposited at the foreshore than at the backshore. Especially gavel content(%) Is very high in northern beaches. The lavel fraction tended to concentrate at the toe of the beach. In addition to gravel. the beach and nearshore bar also tended to be deposite of very coarse sand and the Inner fraction accumulate in the offshore bar, Grainsize analyses of sediment Indicates that the coarsest sands Including gravel accumulate In the beach and nearshore bar, the finer fraction winnowed out by wave action to be deposited In the offshore bar. The beach and nearshore bar sands and gavel are subsequently transported laterally by the wave-driven longshore drift, and finally they come to rest in the distal end of Provincetown Hook. The faller offshore sands are trnasported laterally to the south by net southward-directed longshore current.