• Journal of Environmental Health Sciences
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• v.17 no.2
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• pp.41-47
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• 1991

A study on the effects of volumetric loading rate, surface loading rate and hydraulic. retention time (HRT) for the anaerobic treatment was conducted with the anaerobic fixed-film process using synthetic wastewater at lower temperature than that of conventional anaerobic treatment. The results are as follows 1. Alkalinity and pH value decreased as the hydraulic retention time increased 2. Increase of the volumetric lodaing rate led to increasl of effluent COD concentration and decrease of COD removal efficiency. 3. The removed volumetric loading rate increased linearly according to the increase of the volumrtric loading rate. 4. Similarly, the linear increase of the removed surface loading rate was noticed with an increase of the surface loading rate.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.43-48
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• 2001

Terephthalic acid and ethylene glycol resulting form the weight-reduction process of polyester make trouble in the operation of activated sludge process. Also, polyester weight loss wastewater shows high pH, high organic strength and wide variation of organic loading. Therefore, this study was conducted in order to improve treatment efficiency by activated sludge process with Pseudomonas sp degrading components of polyester weight loss wastewater. The CO $D_{Mn}$ and BO $S_{5}$ of the waste wastewater were 560~3,000 mg/$\ell$ and 8000~3,000 mg/$\ell$, respectively. pH was 11.8~12.3. COD removal efficiency by activated sludge-coagulation process with Pseudomonas sp was 94.1~95.8% for 35 hr of hydraulic retention time. Total organic carbon removal efficiency was 97.1%. Ethylene glycol and terephthalic acid in the wastewater were completely degraded during 32 hr of hydraulic retention time.e.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.11-20
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• 2001

An anaerobic sludge-aerobic fixed-bed biofilm(packed with ceramic support carrier of 1 inch size) reactor system was built up to treat textile wastewater. The efficiency of reactor system was examined by determining the effects of textile wastewater ratio(from 25% to 100% at HRT 24 h). The influent range of SCOD concentration and color were 1,036~1,357 mg/L, and 1,487~1,853 degree, respectively. When textile wastewater ratio was 100% and hydraulic retention time was 24 hours, SCOD removal efficiency by the anaerobic stage were 39.2% 100% and hydraulic retention time was 24 hours, SCOD removal efficiency by the anaerobic stage were 39.2% and the removal efficiency of the whole system were 75.8%. Color removal efficiency by the anaerobic stage were 45.4%(soluble color), and the removal efficiency of the whole system were 70.2%. In the A/A reactor system, the aerobic stage played an important role in removing both color and COD as well as anaerobic stage.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.81-85
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• 2001

The aim of this study was to evaluate on the removal effect of total nitrogen and posphorus in municipal wastewater by decreasing hydraulic retention time(HRT) from 6 hour to 4 hour on CNR process using influent as a Carbon Source. CNR(Cilium Nutrient Romoval) is the process combining $A^2$/O process with cilium media of H2L corporation. The removal efficiencies for BOD$_{5}$, T-N and T-P were 81.1%, 61.4%, 61.4%, respectively. The removal efficiency of nitrogen and posphorus were low by decreasing hydraulic retention time(HRT) from 6 hour to 4 hour on CNR process.s.

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.172-179
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• 1999

In this research, biological treatability test was conduced using seawater flocculated tannery wastewater by fixed biofilm reactor. During one cycle, the removal efficiency of organic corbon obtained with fixed biofilm process for treating tannery wastewater was considerably greater than that with activated sludge process. As the hydraulic retention time increased form 0.5day to 4day, removal efficiency of organic carbon was increased from 72% to 87.3%. Attached biomass in media increased with influent organic loading up to 29g MLSS/L, that could reduce the specific organic loading rate. The continual measurement of attached biomass was possible for the operation of the biofilm reactor. Equal and low nitrication rates were observed in both suspended growth activated sludge process and fixed biofilm process, despite commercial nitrifier was seeded. Through the process of treating the tannery wastewater, EC50 values which is measured by the use of Ceriopdaphnia dubia, were decreased to the extent of 50% after treatment of seawater flocculation and of 83% after biological treatment, respectively, compared to those of the untreated wastewater.

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.110-116
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• 1999

This study was conducted to investigate the contaminants removal efficiency and the optimal operating parameters by the internal recycle rate (IRR) in the combining A2/O process with fixed film. The average removal efficiency of BOD and COD was 92.5%~94.6%, 73.9%~87.0% in RUN 1 and 91.9%~94.7%, 77.7%~89.0% in RUN 2, respectively. Organic removal efficiency, at two different hydraulic retention time of 10 and 14hr, was similar. At 50% of the internal recycle rate, organic removal efficiency was somewhat higher than the other. Total nitrogen (T-N) and total phosphorus (T-P) were removed, highly, at 50% of internal recycle rate. It could be suggested by this study that the optimum internal recycle rate is 50% and hydraulic retention time is 14hr.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.371-377
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• 2010

The purpose of this study is to investigate treatment efficiency in dyeing wastewater treatment by the high rate aeration system(HRA) and a combination of the HRA with magnetized wastewater treatment system(MWS). At the hydraulic retention time of 16hr, 24hr, 30hr, BOD removal efficiencies of HRA system were 93%, 96% and 98%, combination of the HRA with MWS system were 94%, 96.8% and 98.2%, respectively. In ease of COD, at the hydraulic retention time of 16hr, 24hr, 30hr, COD removal efficiencies of HRA system were 66%, 77.1% and 83.1%, combination of the HRA with MWS system were 70.2%, 80.1% and 86.6%, respectively. The comparison of the HRA and combination of the HRA with MWS, effluent BOD of the former was 22.7mg/${\ell}$ and the latter was 19.4mg/${\ell}$, theretore biological treatment efficiency identified to increase by the MWS.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.95-100
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• 1999

Process intensification without any increase in bed requires the exploitation of fluid mechanical phenomena as the basis for elegant solutions to the process engineering problems which result from the need to retain and control the immobilized biomass, and for biomass recovery. The fluidized bed biological reactor provides a solution to these needs. The wastewater treatment characteristics of the fluidized bed was filled with sand media. Indirect aeration were studied experimentally. The researcher was filled with sand particle size(0.60~0.42mm) in three reactors with different section area(A)/height(H), in the state BOD loading 4.5kg-$BOD_5/m^3$ㆍd, and under the fixed state of hydraulic retention time for around 32 minutes.

• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.808-812
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• 2013

A new type of microbial fuel cell (MFC) with anaerobic membrane filter was designed to produce bioelectricity and to treat domestic sewage at relatively high organic loading rate (OLR) of $6.25kgCOD/m^3/day$ and short hydraulic retention time (HRT) of 1.9 h. A following aeration system was applied to ensure effluent water quality in continuous operation. Glucose was supplemented to increase the influent concentration of domestic sewage. Influent substrate of 95% was removed via the MFC and following aeration system and the corresponding maximum power density was $25.6mW/m^3$. External resistor of $200{\Omega}$ and air-cathode system contributed better MFC performance comparing to $2000{\Omega}$ and dissolved oxygen as a catholyte.

• KSBB Journal
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• v.20 no.6
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• pp.443-446
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• 2005

Hydrogen fermentation from food waste was attempted at different hydraulic retention time(HRT, 18-42 h). A continuous reactor fed with ground, alkali-treated and diluted food waste(average VS 4.4%) exhibited stable hydrogen production during 126 days. Hydrogen production depended on HRT, resulting in the maximum values of 25.8 mL $H_2/g\;VS_{added}$, 0.36 mol $H_2/mol\;hexose_{added}$ and 0.91 L $H_2/L/d$ at HRT 30 h. n-Butyrate and isopropanol production increased with hydrogen production increased, while acetate production decreased. The fermentation efficiency ranged from 53.3 to 65.7%, which implied that hydrogen fermentation would substitute conventional acidogenesis of food waste.