• Title/Summary/Keyword: COD fractionation

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Diagnosis of Wastewater Treatment Processes through the Wastewater COD Fractionation and Process Simulation I : Wastewater COD Fractionation (유입하수 유기물 분류 및 공정모사를 통한 하수처리공정 진단 I : 유입하수 유기물 분류)

  • Choi, Young-Gyun;Chung, Tai-Hak
    • Journal of Korean Society of Water and Wastewater
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    • v.21 no.5
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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.

A Comparative Study on COD Fractionation Methods of Wastewater (하수의 COD 분류 시험 방법에 관한 비교 연구)

  • Kim, Sung-Hong;Yun, Jung-Won;Choi, Young-Gyun
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.4
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    • pp.387-394
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    • 2010
  • The influent COD of municipal wastewater has been divided into 4 fractions; readily soluble biodegradable, slowly particulate biodegradable, soluble and particulate unbiodegradable COD. The mathematical modeling of biological wastewater treatment processes and the design and operation of nutrient removal plants require a reliable and accurate estimate of the composition of influent wastewater COD. COD utilization rate is proportional to the oxygen uptake rate(OUR), so a batch biodegradation test with OUR measurement has been effectively used for the determination of COD fractionation. But the mathematical model of COD utilization and heterotrophs synthesis is essential to interpret the OUR measurement. Mamais method is another method for determining readily biodegradable soluble COD. Like the OUR test method, batch biodegradation test is necessary but it does not require mathematical model. These two methods for determining COD fractionation are introduced here in detail. Experimental results showed that COD composition by Mamais method is not different to that by OUR test method so, either of them can be used.

Evaluation of the COD Fractionation Capability Using Storage Microorganism from EBPR Process (EBPR 공정내 저장 미생물을 이용한 유입수 분율 분석능 평가)

  • Kim, Youn-Kwon;Seo, In-Seok;Kim, Hong-Suck;Kim, Ji-Yeon
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.4
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    • pp.25-31
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    • 2004
  • In conventional activated sludge process, COD fractions in wastewater are important parameters, significantly. Depending on characteristics of influent COD fractionation, activated sludge process requires a major change of a process operation to ensure meeting a stricter standards. In order to validate and evaluate the accuracy of the traditional COD fractionation methodologies, readily and slowly biodegradable COD was mixed using glucose and peptone as a sole carbon source in a synthetic wastewater, respectively. In this research, prediction of the COD fraction was made using the OUR(Oxygen Utilization Rate) and the NUR(Nitrate Utilization Rate) experiments. The result showed that COD fractions calculated by OUR experiment were similar to the composition of synthetic wastewater. On the other hand, it was found that an error was generated during the NUR experiment. This error was due to the intracellular storage period for storage microorganisms such as PAOs, and the error in COD fraction was observed about 8-14 % in terms of Total COD.

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Respirometry for COD Fractionation of Wastewater (미생물 호흡률 분석에 의한 하수의 유기물 분류)

  • Choi, Younggyun;Kim, Gyudong;Kim, Heejun;Kim, Yunjung;Chung, Taihak
    • Journal of Korean Society of Water and Wastewater
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    • v.17 no.4
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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.

A Study of Organic Matter Fraction Method of the Wastewater by using Respirometry and Measurements of VFAs on the Filtered Wastewater and the Non-Filtered Wastewater (여과한 하수와 하수원액의 VFAs 측정과 미생물 호흡률 측정법을 이용한 하수의 유기물 분액 방법에 관한 연구)

  • Kang, Seong-wook;Cho, Wook-sang
    • Journal of the Korea Organic Resources Recycling Association
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    • v.17 no.1
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    • pp.58-72
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    • 2009
  • In this study, the organic matter and biomass was characterized by using respirometry based on ASM No.2d (Activated Sludge Model No.2d). The activated sludge models are based on the ASM No.2d model, published by the IAWQ(International Association on Water Quality) task group on mathematical modeling for design and operation of biological wastewater treatment processes. For this study, OUR(Oxygen Uptake Rate) measurements were made on filtered as well as non-filtered wastewater. Also, GC-FID and LC analysis were applied for the estimation of VFAs(Volatile Fatty Acids) COD(S_A) in slowly bio-degradable soluble substrates of the ASM No.2d. Therefore, this study was intended to clearly identify slowly bio-degradable dissolved materials(S_S) and particulate materials(X_I). In addition, a method capable of determining the accurate time to measure non-biodegradable COD(S_I), by the change of transition graphs in the process of measuring microbial OUR, was presented in this study. Influent fractionation is a critical step in the model calibrations. From the results of respirometry on filtered wastewater, the fraction of fermentable and readily biodegradable organic matter(S_F), fermentation products(S_A), inert soluble matter(S_I), slowly biodegradable matter(X_S) and inert particular matter(X_I) was 33.2%, 14.1%, 6.9%, 34.7%, 5.8%, respectively. The active heterotrophic biomass fraction(X_H) was about 5.3%.

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Effect of H2O2 Injection and Temperature Changing on the Organic Carbon Fraction in Chromatogram Dissolved Organic Carbon (CDOC) from Thermal Pretreatment (H2O2 주입과 온도변화가 열적 전처리 후 발생 슬러리의 CDOC 유기탄소분율에 미치는 영향평가)

  • Kim, Hee-Joong;Kim, Tae-Kyoung;Kim, Youn-Kwon
    • Journal of Korean Society of Environmental Engineers
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    • v.38 no.3
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    • pp.110-116
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    • 2016
  • Biogas yields point of view, the possibility of reusing excess sludge treated by thermal pretreatment for the purpose of improving the efficiency of the anaerobic digestion process has been investigated in recent year. Thermal pretreatment technology was considered as a pretreatment technique to improve excess sludge properties because of the solubilization of particulate organics. As a view point of sludge reduction and recycle, however, many researchers focused on the ability of particulate hydrolysis and COD solubilization under a high temperature, and few reports have addressed on the physical/chemical characteristics changing. This research was performed to evaluate the effects of a various temperature and chemical additives on carbon formation and fractionation in treated slurry from thermal pretreatment. Based on the results, it was revealed that oxidants injection and temperature changing have significantly caused the change of carbon fractions in slurry from thermal pretreament. Especially, it was considered that the efficiencies of particle hydrolysis increased with the increase of the reaction temperature. Low molecular weight(Mw < 350 g/mol) organic carbon formation increased with the increase of oxidants injection. It was expected that results of this research will provide an overview of the characteristics of thermal pretreatement for excess sludge reduction and recycle.

The Role of Primary Clarifier in Biological Processes for Nutrient Removal (생물학적 질소·인제거 공정에서 일차 침전지의 영향)

  • Whang, Gye-Dae;Kim, Tae-Kyung
    • Journal of Korean Society on Water Environment
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    • v.23 no.1
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    • pp.19-26
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    • 2007
  • The lab-scale BNR processes fed with Municipal Wastewater Before or After Primary Clarifier (MWBPC or MWAPC) were operated to observe the behavior of particle organic matter in terms of nitrification and denitrification efficiency. As a result of the fractionation of the COD from MWBPC or MWAPC using an aerobic respirometric serum bottle reactor, the total mass of biodegradable organic matter from MWBPC is about 52% greater than the mass from MWAPC. Batch reactors were operated to observe the effect of the Particulate Organic Matter (POM) on substrate utilization for denitrification. Although the consumption of POM for denitrification was observed, the increment of the Specific Denitrification Rate (SDNR) was not great. In terms of the effect of POM on nitrification at different HRTs, activate sludge reactors were operated to determine the optimal HRT when MWBPC and MWAPC were fed relatively. All reactors showed a great organic matter removal efficiency. Reactors fed with MWAPC had obtained the nitrification efficiency above 90% when the HRT of 4 hr, at least, was maintained, while reactors fed with MWBPC had same efficiency when the HRT longer than 5 hr was kept. Three parallel $A^2/O$ systems fed with MWBPC or MWAPC relatively were operated to investigate the effects of POM on BNR processes with varying the HRT of an anoxic reactor. For all systems, the efficiency of organic matter removal and denitrification, respectively, was great and about the same. In case of denitrification efficiency, system with MWAPC had 1.5% lower than system with MWBPC at the same HRT of anoxic reactor of 2 hr, and the increasing the HRT of the anoxic reactor by 1 hr in systems fed with MWBPC resulted in a 3.5% increment. The denitrification rate was similar while the consumption of organic matter in systems fed with MWBPC was higher than system fed with MWBPC. It suggests that POM in MWBPC was not be used significantly as a substrate for denitrification in system with the HRT of 3 hr of an anoxic reactor.