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1.
Nam Hai-Uk Lee Tae-Ho Kim Young -O. Park Seung-Han Park Tae-Joo 《Korean Journal of Chemical Engineering》2004,21(3):635-639
The influence of an aerobic fixed-biofilm activity, microbial ecosystem and mass transfer with respect to HRT variation in
a BNR (biological nutrient removal) system has been investigated in this study. The process used in this study was an anoxic
(1)/aerobic (1)/anoxic (2)/aerobic (2) system. The study was demonstrated by several kinds of techniques such as INT-dehydrogenase
activity (DHA), INT (2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetra-zolium chloride), DAPI (4’,6’-diamidino-2-phenylindole
hydrochloride), and microelectrode. The study used by synthetic wastewater and HRT variation demonstrated that the DHA activity,
density and heterotrophs/autotrophs ratio increased, as the HRT decreased from 8 hr to 4 hr. In comparing two aerobic reactors
in fixed-biofilm process, the first aerobic reactor of the higher C/N ratio showed higher heterotrophs/autotrophs ratio and
microbial activity than the second aerobic reactor. It was therefore concluded that the heterotrophs/autotrophs ratio and
microbial activity were a greater influence on the first aerobic reactor, as organic loading rate was increased by HRT variation. 相似文献
2.
Hai-Uk Nam Jong-Hyun Lee Young-O Kim Young-Gyu Kim Tae-Joo Park 《Korean Journal of Chemical Engineering》1998,15(4):429-433
In order to remove nitrogen and phosphorus simultaneously and to develop a compact process for retrofitting a conventional
activated sludge system, a new fixed-biofilm reactor was designed and tested employing an operation strategy with three and
two reaction phases : anaerobic/anoxic/aerobic (Run-1) and anoxic/aerobic (Run-2). Four kinds of HRT (4, 6, 8 and 10 h) were
varied to investigate the effect of nitrification and denitrification in each reactor. The results of the experiments are
summarized as follows. All removal rates of COD, T-N and T-P in the water treated in Run-1 were higher than those of Run-2.
The average values of COD, T-N and T-P in the treated water were reduced to 5.0 mg/L, 5.6 mg/L and 3.1 mg/L in case of Run-1.
The COD and T-N removal efficiencies of Run-1 were higher than that of Run-2, but the difference between Run 1 and Run 2 was
almost negligible. More than 60 % T-P removal efficiency could be achieved when the HRT was above 8 hour, but the efficiency
was sharply decreased to 36% as the HRT was decreased to 4 hour in case of Run-1. Although the removal efficiency of T-P in
Run-2 decreased by 56 % compared with that of Run-1, the fixed biofilm reactor using SAC media reduced the volume of reactor,
and high-level COD and T-N removal from domestic wastewater was performed ; stable effluent quality was thereby achieved.
The performance of Run 2 with no anaerobic reactor was mostly similar to that of Run 1 with an anaerobic reactor, except for
T-P removal. Hence, according to these results, anoxic and aerobic processes using SAC media could be possible for removing
organics and nutrients from municipal wastewater, in case phosphorus removal is not considered for municipal wastewater with
low concentration of phosphorus. 相似文献
3.
Adopting various process configurations may perform biological nutrient removal (BNR) from sewage. To get a compact BNR process,
biofilm reactors were chosen for nitrification and denitrification. Enhanced biological nitrogen and phosphorus removal in
a new fixed biofilm reactor was investigated in operation strategies with two reaction phases: anaerobic/anoxic/aerobic process
with post-anoxic/aerobic biofilm process (Run 2A) and Run 2A with exogenous carbon sources for denitrifying and removing phosphorus
(Run 2B). The influent used was “J” WWTP influent that consisted of wastewater from nearby a factory district area, leachate,
and sewage. Therefore, the influent contained a great deal of refractory organic compound. The mean concentrations of COD,
NH
4
+
-N and T-P in the influent were about 297.0 mg/L, 64.92 mg/L and 2.63 mg/L, respectively. The C: N: P ratio of influent was
113: 25: 1 and it was not suitable for growth of microorganism compared with 100: 5: 1 of proper growth C:N:P ratio. But,
at a total HRT of the system of 16 hours in Run 2, the system worked successfully obtaining removal of COD, T-N and T-P of
the case of Run 2A, 80.1 %, 74.9 %, and 50.8 %, respectively, and Run 2B(c) with exogenous carbon source (Na-acetate) obtained
86.2 % T-N removal efficiency. The results of this research showed that an innovative nutrient removal system (INRS) process
packed with SAC media could be applicable for treatment of nutrients from municipal wastewater. 相似文献
4.
Im-Gyu Byun Ju-Hyun Ko Young-Rok Jung Tae-Ho Lee Chang-Won Kim Tae-Joo Park 《Korean Journal of Chemical Engineering》2005,22(6):910-916
Batch experiments using acclimated sludge to sulfur utilizing autotrophic denitrification were performed to determine the
applicability of spent sulfidic caustic in autotrophic denitrification as alternative sulfur and alkalinity sources. Fluorescence
insitu hybridization (FISH) analysis showed that the microbial community of β-proteobacteria/ Eubacteria increased from 45% to 69%
during enrichment period and nitrate removal reached up to 84% under this enriched sludge condition. In thiosulfate utilizing
autotrophic denitrification, the initial condition at a sulfur/nitrate (S/N) ratio of 1.5 showed higher nitrate removal with
95.9%, and nitrate removal could be expressed by a first-order function of biomass concentration if all parameters such as
pH, alkalinity and S/N ratio were in the optimum range. In spent sulfidic caustic utilizing autotrophic denitrification, the
sulfate formation ratios to nitrate reduction were lower than those in thiosulfate utilizing autotrophic denitrification with
a range of 2.65 to 2.78, and nitrate removal was over 95% at 1.0 and 1.5 S/N ratios. For S/N ratios of 1.0 and 1.5, initial
alkalinities were sufficient to maintain optimum pH range of autotrophic denitrification. Furthermore, well enriched seeding
sludge showed good activity of autotrophic denitrification at pH over 10. Therefore, spent sulfidic caustic could be effectively
applied to autotrophic denitrification as an alternative sulfur source and an alkalinity source 相似文献
5.
Min-Gyu Song Jin-Hwe Kweon Jin-Ho Choi Jai-Hyun Byun Min-Hwan Song Sang-Joon Shin Tae-Joo Lee 《Composite Structures》2010
The present paper experimentally addresses the effect of manufacturing methods on the strength of composite bonded joints. A total of 391 specimens, manufactured by four different fabrication methods, were tested. For each method, various overlap lengths, adherend thicknesses and lay-up patterns were examined. The failure strength was higher in thicker adherend joints and lower in specimens with larger overlap length. Results showed that the secondary bonded joints had higher strength than the co-bonded and adhesively cocured joints and yielded similar strength compared with the non-adhesive cocured case. Changes in the stacking sequence also affected the interlaminar stresses and failure loads. 相似文献
6.
Jeung-Jin Park Im-Gyu Byun So-Ra Park Tae-Joo Park 《Korean Journal of Chemical Engineering》2008,25(6):1448-1455
Tests were performed to investigate nitrifying bacterial communities and activities in aerobic biofilm reactors with different
temperature conditions, denaturing gradient gel electrophoresis (DGGE) based on polymerase chain reaction targeting 16S rRNA
and amoA gene, fluorescence in situ hybridization (FISH) and dehydrogenase activity (DHA). T1, T2 and T3 reactors operated at different temperatures (5, 10 and
30 °C, respectively) were set up in the thermostat and acclimated. Nitrification was considerably limited in T1 and T2 reactors.
DGGE revealed specific genera of ammonium-oxidizing bacteria (AOB) and some Nitrosomonas genera endured at the low temperatures. FISH revealed a decreased distribution ratio between AOB and nitrate-oxidizing bacteria
at 5 °C, and showed that the decrease of AOB also affected the nitrification failure in the aerobic biofilm reactor. The mean
attached biomass of the T1, T2 and T3 reactors was 69.6, 80.6 and 112.9 mg/L, respectively, and the 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride dehydrogenase activity of the respective reactors was 73.6, 87.4 and 134.2 mgO2*/g VSS/day. The results demonstrate that a low temperature condition in an aerobic biofilm reactor decreases the attached
biomass, distribution ratio and activity of nitrifying bacteria, and produces a change in the composition of the AOB species,
which results in the failure of nitrification. 相似文献
7.
Jeung-Jin Park Im-Gyu Byun So-Ra Park Jae-Ho Lee Seung-Han Park Tae-Joo Park Tae-Ho Lee 《Journal of Industrial and Engineering Chemistry》2009,15(3):316-322
Caustic is utilized in petrochemical plants for the removal of hydrogen sulfide (H2S) from a variety of hydrocarbon streams. Because spent sulfidic caustic (SSC) harbors a high level of H2S and high alkalinity, it was injected into the anoxic zones of the biological nitrogen removal process as the electron donor and buffering agent for sulfur-based autotrophic denitrificaton. In order to determine the optimal SSC dosage, a modified Ludzack–Ettinger (MLE) process was first conducted at laboratory scale. As the result of the lab-scale experiments, the chemical oxygen demand (COD) increment of effluent and nitrification failure were observed, because SSC harbors barely biodegradable matter, and the caustic content was high, in accordance with the requirements. Thus, during the pilot-scale experiments, a hybrid Bardenpho process was designed and the SSC was neutralized from pH 13.3 to 11.5. These strategies were successful because no COD increment of effluent was observed and the pH of the unit process was stable. The heterotrophic and autotrophic denitrification ratios at each condition were calculated and, as the end product of sulfur-based autotrophic denitrification, the sulfate concentration was monitored. 相似文献
8.
Jeung-Jin Park So-Ra Park Dong-Jin Ju Jeong-Keun An Im-Gyu Byun Tae-Joo Park 《Korean Journal of Chemical Engineering》2008,25(3):542-547
Spent sulfidic caustics (SSCs) produced from petrochemical plants contain a high concentration of hydrogen sulfide and alkalinity,
and some organic matter. Most of the SSCs are incinerated with the auxiliary fuel causing secondary pollution problems. The
reuse of this waste is becoming increasingly important in terms of economical and environmental viewpoints. To denitrify wastewater
with a low COD/N ratio, additional carbon sources are required. Therefore, autotrophic denitrification has received increasing
attention. In this research, SSCs were injected as electron donors for sulfur-based autotrophic denitrification in a modified
Ludzack-Ettinger (MLE) process. According to the variations in the SSCs dosage, the efficiencies of COD, nitrification and
TN removal were evaluated. Heterotrophic denitrification by organic matter and autotrophic denitrification by SSCs were also
investigated. As a result, adequate injection of SSCs showed stable autotrophic denitrification. To investigate some of the
harmful effects of SSCs, fluorescence in situ hybridization (FISH) for nitrifying bacteria and Thiobacillus denitrificans was performed. Ammoniaoxidizing bacteria (AOB) and Nitrospira genus showed a similar pattern. Excessive injection of SSCs made nitrifying bacteria decrease and nitrification failure occur
because of the high pH caused by the SSCs. The distribution of T. denitrificans was relatively uniform as SSCs were injected. This result means that T. denitrificans are available at high pH. 相似文献
9.
Monitoring of bioventing process for diesel-contaminated soil by dehydrogenase activity, microbial counts and the ratio ofn-alkane/isoprenoid 总被引:1,自引:0,他引:1
Im-Gyu Byun Hae-Uk Nam Seung Koo Song In-Seong Hwang Tae-Ho Lee Tae-Joo Park 《Korean Journal of Chemical Engineering》2005,22(6):917-921
Monitoring parameters were evaluated for a bioventing process that was designed to treat soils contaminated with diesel fuel.
Statistical analyses were conducted to evaluate correlations between total petroleum hydrocarbon concentrations in the contaminated
soil and physico-chemical parameters of soil such as microbial counts, dehydrogenase activity, andn-alkane/isoprenoid ratio. The correlation coefficients (r2) obtained showed that TPH concentrations in the bioventing system were strongly correlated with dehydrogenase activity (DHA),
total heterotrophic bacterial count, and hydrocarbon utilizing bacterial count. Thus, it was concluded that these parameters
could useful monitoring parameters for soils contaminated with diesel fuel 相似文献
10.
Fenton oxidation process control using oxidation-reduction potential measurement for pigment wastewater treatment 总被引:1,自引:0,他引:1
Young-O?Kim Hai-Uk?Nam Yu-Ri?Park Jong-Hyun?Lee Tae-Joo?Park Tae-Ho?LeeEmail author 《Korean Journal of Chemical Engineering》2004,21(4):801-805
The Fenton oxidation process was applied as a pretreatment process to degrade non-biodegradable organic matters in pigment
wastewater. It was necessary to continuously measure the fluctuating concentration of organics in the pigment wastewater and
to determine the amount of Fenton’s reagent required to oxidize the organics. Batch and continuous flow tests were used to
evaluate the relationship between the concentration of organics (CODCr) and the amount of Fenton’s reagent required to achieve a sufficient oxidation of the organics. On-line measurements of the
oxidation-reduction potential (ORP) value in the batch and continuous flow tests showed that the maximum ORP values were highly
related to the organic concentrations (expressed as CODCr) and the Fenton’s reagent dosage (expressed as H2O2 concentration). The empirical equation was [CODCr]=8808+0.494[H2O2]-14.6ORP. A control program of Fenton’s reagent dosage based on the empirical equation was applied to control of a pilot
scale Fenton oxidation process using ORP measurement. The concentration of organics predicted with the control program well
agreed with the observed concentration of organics in the pigment wastewater. The variation of the effluent organics concentration
of the controlled Fenton oxidation process was significantly reduced compared to that of a process without the control system.
These results suggested that the control system of Fenton’s reagent dosage using ORP measurement would be applicable to the
Fenton oxidation process for efficient pretreatment of pigment wastewater. 相似文献