• Environmental Engineering Research
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• v.24 no.2
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• pp.309-317
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• 2019

This study evaluated the kinetics of acrylamide (AM) biodegradation by mixed culture bacteria and Enterobacter aerogenes (E. aerogenes) in sequencing batch reactor (SBR) systems with AQUASIM and linear regression. The zero-order, first-order, and Monod kinetic models were used to evaluate the kinetic parameters of both autotrophic and heterotrophic nitrifications and both AM and chemical oxygen demand (COD) removals at different AM concentrations of 100, 200, 300, and 400 mg AM/L. The results revealed that both autotrophic and heterotrophic nitrifications and both AM and COD removals followed the Monod kinetics. High AM loadings resulted in the transformation of Monod kinetics to the first-order reaction for AM and COD removals as the results of the compositions of mixed substrates and the inhibition of the free ammonia nitrogen (FAN). The kinetic parameters indicated that E. aerogenes degraded AM and COD at higher rates than mixed culture bacteria. The FAN from the AM biodegradation increased both heterotrophic and autotrophic nitrification rates at the AM concentrations of 100-300 mg AM/L. At higher AM concentrations, the FAN accumulated in the SBR system inhibited the autotrophic nitrification of mixed culture bacteria. The accumulation of intracellular polyphosphate caused the heterotrophic nitrification of E. aerogenes to follow the first-order approximation.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.271-278
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• 1993

Optimal biodegradation kinetics models to the initial nonylphenol ethoxylates-30 concentration were investigated and had been fitted by the linear regression. Microorganisms capable of degrading nonylphenol ethoxylates-30 were isolated from sewage near Ulsan plant area by enrichment culture technique. Among them, the strain designated as EL-10K had the highest biodegradability and was identified as Pseudomonas from results of taxonomical studies. The optimal conditions for the biodegradation were 1.0 g/ι of nonylphenol ethoxylates-30 and 0.02 g/ι of ammonium nitrate at pH 7.0 and 3$0^{\circ}C$. The highest degradation rate of nonylphenol ethoxylates-30 was about 89% for 30 hours incubation on the optimal condition. Biodegradation data were fit by linear regression to equations for 3 kinetic models. The kinetics of biodegradation of nonylphenol ethoxylates was best described by first order model for 0.1 $\mu\textrm{g}$/ι nonylphenol ethoxylates-30 ; by Monod no growth model and Monod with growth model for 0.5 $\mu\textrm{g}$/mι and 1.0, 5.0 $\mu\textrm{g}$/mι, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.858-864
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• 2014

In this study, The effects of empty bed contact time (EBCT) and water temperature on the biodegradation of 8 synthetic fragrances (SFs) in biological activated carbon (BAC) process were investigated. Experiments were conducted at two water temperatures (7 and $18^{\circ}C$) and three EBCTs (5, 10 and 15 min). Increasing EBCT and water temperature increased the biodegradation efficiency of SFs in BAC column. Pentalide and ambrettolide were the highest biodegradation efficiency, but DPMI and ADBI were the lowest. The kinetic analysis suggested a pseudo-first-order reaction model for biodegradation of 8 SFs at various water temperatures and EBCTs. The pseudo-first-order biodegradation rate constants ($k_{bio}$) of 8 SFs ranging from $0.1184{\sim}0.6545min^{-1}$ at $7^{\circ}C$ to $0.3087{\sim}0.9173min^{-1}$ at $18^{\circ}C$. By increasing the water temperature from $7^{\circ}C$ to $18^{\circ}C$, the biodegradation rate constants ($k_{bio}$) were increased 1.4~2.6 times.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.739-746
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• 2014

In this study, The effects of empty bed contact time (EBCT) and water temperature on the biodegradation of 8 UV filters in biological activated carbon (BAC) process were investigated. Experiments were conducted at two water temperatures (7 and $18^{\circ}C$) and three EBCTs (5, 10 and 15 min). Increasing EBCT and water temperature increased the biodegradation efficiency of UV filters in BAC column. EHMC and BZC were the highest biodegradation efficiency, but BP and 4-MBC were the lowest. The kinetic analysis suggested a first-order reaction model for biodegradation of 8 UV filters at various water temperatures and EBCTs. The first-order biodegradation rate constants ($k_{bio}$) of 8 UV filters ranging from $0.2730{\sim}0.6365min^{-1}$ at $7^{\circ}C$ to $0.4824{\sim}0.8743min^{-1}$ at $18^{\circ}C$. By increasing the water temperature from $7^{\circ}C$ to $18^{\circ}C$, the biodegradation rate constants ($k_{bio}$) were increased 1.5~2.1 times.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.7
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• pp.404-411
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• 2015

In this study, the effects of empty bed contact time (EBCT) and water temperature on the biodegradation of 9 halonitromethanes (HNMs) in biological activated carbon (BAC) process were investigated. Experiments were conducted at three water temperatures ($10^{\circ}C$, $15^{\circ}C$ and $25^{\circ}C$) and three EBCTs (5, 10 and 15 min). Increasing EBCT and water temperature increased the biodegradation efficiency of HNMs in BAC column. Dibromochloronitromethane (DBCNM) and tribromonitromethane (TBNM) showed the highest biodegradation efficiency, but chloronitromethane (CNM) and dichloronitromethane (DCNM) were the lowest. The kinetic analysis suggested a pseudo-first-order reaction model for biodegradation of 7 HNMs at various water temperatures and EBCTs. The pseudo-first-order biodegradation rate constants ($k_{bio}$) of 7 HNMs ranged from $0.0797{\sim}0.7657min^{-1}$ at $10^{\circ}C$ to $0.1245{\sim}1.8421min^{-1}$ at $25^{\circ}C$. By increasing the water temperature from $10^{\circ}C$ to $25^{\circ}C$, the biodegradation rate constants ($k_{bio}$) were increased 1.6~2.4 times.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.44-54
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• 2003

A kinetic model for evaluating effects of surfactant on the biodegradation of HOC(hazardous organic chemicals) in soil-slurry systems was developed. The model includes the partition of HOC and surfactant, the dissolved-, micellar-, and sorbed-phase biodegradation, the enhanced solubilization of HOC by surfactant addition, and the mass transfer of HOC. Phenanthrene as HOC and Trition X-100, Tergitol NP-10, Igepal CA-720, and Brij 30 were used in the model simulations. The biodegradation rate was increased even with a small micellera-phase bioavailability. The biodegradation was not greatly enhanced due to decreased aqueous HOC concentration by increasing surfactant dose in both cases with and without micellar-phase bioavailability. The effect of sorbed-phase biodegradation on total biodegradation rate was not highly important compared to aqueous- and micellar-phase biodegradation. The model can be applied for surfactant screening and optimal design of surfactant-based soil bioremediation process.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.3
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• pp.124-131
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• 2017

In this study, We investigated the effects of water temperature and empty bed contact time (EBCT) on the biodegradability of 8 blood lipid lower agents (BLLAs) in biological activated carbon (BAC) process. Experiments were conducted at three water temperatures ($8^{\circ}C$, $16^{\circ}C$ and $24^{\circ}C$) and three EBCTs (5 min, 10 min and 15 min). Increasing water temperature and EBCT increased the biodegradation efficiency of BLLAs in BAC process. Simvastatin and fenofibrate were the highest biodegradation efficiency, but atorvastatin and clofibric acid were the lowest. The kinetic analysis suggested a pseudo-first-order reaction model for biodegradation of 8 BLLAs at various water temperatures and EBCTs. The pseudo-first-order biodegradation rate constants ($k_{bio}$) of clofibric acid and atorvastatin were $0.0075min^{-1}$ and $0.0122min^{-1}$ at $8^{\circ}C$, and were $0.0540min^{-1}$ and $0.0866min^{-1}$ at $24^{\circ}C$, respectively. By increasing the water temperature from $8^{\circ}C$ to $24^{\circ}C$, the biodegradation rate constants ($k_{bio}$) were increased 7.1~7.2 times.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.63-67
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• 1994

A microorganism showing degradative activity towards benzene, toluene and ${\rho}-xylene$ (BTX) was isolated from an activated sewage sludge and was tentatively identified as Pseudomonas fluorescence BE103. This strain was found to utilize benzene and toluene as growth substrates, but to degrade ${\rho}-xylene$ in the obligate presence of a growth substrate. The metabolic product resulted from the cometabolism of ${\rho}-xylene$ was identified as 3, 6-dimethylpyrocatechol by LC/MS analysis, and the metabolic pathway was analyzed to be similar to the tod pathway. From the kinetic studies done regarding BTX biodegradation using Pseudomonas fluorescence BE103, it was revealed that the cometabolism of ${\rho}-xylene$ is significantly affected by the ratio of growth substrate concentration to biomass concentration, and that the cometabolism of ${\rho}-xylene$ initiates only when this ratio was about 0.03.

• KSBB Journal
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• v.19 no.2
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• pp.143-147
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• 2004

Biodegradation of dimethyl sulfide (DMS) was studied in a batch culture using Gordonia sihwaniensis PKL-1 isolated from a compost biofilter after 100 days of operation for the removal of volatile organic compounds. Optimal pH and temperature for the removal of DMS were 7 and $25^{\circ}C$, respectively. The Michaelis-Menten kinetic constants for DMS removal, $\upsilon_{max}$ and $K_s$, were 0.0016 mg/(mg-protein)ㆍhr, and 8.05 mg/L, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.187-193
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• 2008

Biological removal capacities for volatile organic compounds (VOCs) were determined using a yeast strain, Candida tropicalis. In this study, VOCs including toluene, benzene, p-xylene, and styrene as single substrates or mixtures were tested in the batch culture of the yeast strain. In addition, a kinetic model was applied to evaluate substrate interactions between the VOCs. The yeast strain was able to biodegrade each VOC effectively as a growth substrate, implying it could applied to wide range of VOCs. When the yeast strain was subjected to VOCs in mixtures, the biodegradation rate of one substrate were either increased (stimulated) or decreased (inhibited) by the presence of the others. Both benzene and toluene were inhibited by the other VOCs, and substrate interaction parameters estimated in the model indicated that styrene was the strongest inhibitor for the benzene and toluene biodegradation. Meanwhile, the biodegradation of p-xylene and styrene was stimulated by the presence of either benzene or toluene. The biodegradation rate of p-xylene was significantly increased especially by the presence of toluene, and the styrene biodegradation was enhanced greatly by the benzene addition. The results of the substrate interaction by the yeast strain suggest that the biodegradation rates for the VOCs in mixtures should be carefully evaluated. Furthermore, the competitive inhibition coefficient could be applied as a useful index to determine the substrate interaction