• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.11
• /
• pp.1935-1944
• /
• 2000

This research was performed to investigate the effects of the location of recirculation port on the wastewater treatment efficiency of an anaerobic hybrid reactor consisted of a fluidized bed and a packed bed. The recirculation port was located either at the top of the packed bed (Reactor 2) or above the fluidized bed (Reactor 1). Media for the fluidized bed and the packed bed were granular activated carbon and Pall ring-type plastic media. respectively. At organic loading rates(OLR) up to $6.2kg\;COD/m^3-day$. Reactor 2 showed somewhat better performance than Reactor 1 with COD removal efficiencies of 85.0-95.2%. The COD removal efficiencies of the reactors drastically deteriorated at OLRs above $6.2kg\;COD/m^3-day$, and the tendency was more severe for Reactor 1 than for Reactor 2. Eventhough the two reactors showed similar effluent SS concentrations at OLRs below $3.6kg\;COD/m^3-day$, Reactor 2 showed higher effluent SS concentrations than Reactor 1 at OLRs above $5.3kg\;COD/m^3-day$. Reactor 2 was stabler than Reactor 1 with a methane production rate of $5.5kg\;COD/m^3$-day at the OLR of $13.3kg\;COD/m^3-day$. An abrupt increase in effluent volatile acid concentration was observed at the OLR of $6.2kg\;COD/m^3-day$ for Reactor 1 and $7.1kg\;COD/m^3-day$ for Reactor 2. and the increase was greater in Reactor 1. In conclusion. the range of OLR for adequate treatment in the hybrid reactor was determined according to the location of the internal recirculation port. It is more desirable for higher OLRs to locate the recirculation port at the top of the packed bed in order to utilize the whole volume of the reactor.

• Journal of the Korean Applied Science and Technology
• /
• v.31 no.4
• /
• pp.669-678
• /
• 2014

The amount of waste water generated from the domestic sources is consistently increasing in proportion to economic growth, and the conventional activated sludge process is widely being used for general waste water treatment. But the ministry of environment becomes stringthent treatment standards of N and P (less than 20mg/L of N, 2mg/L of P) to prevent the eutrophication of lake water, and therefore highly advanced treatment technology is required not only in the existing treatment plants where the activated sludge process is being used, but also in newly constructed treatment plants for the treatment of N and P. This study is aimed at highly operating the engineering technology method was developed by domestic to eliminate N and P at the same time. Experiments were conducted in the treatment plant located in Yong In city. The bioreactor was started from the principal equipment for the elimination of N and P and the elimination of organic compounds. It consists of an internal recycle piping from the end of the aerobic tank to the anoxic tank and external recycle piping from the final settling basin to the denitrification tank. By experiment of 4 types separate inflow of waste water to the denitrification tank and the anaerobic tank, and changes in staying time at the anoxic tank and the aerobic tank, the elimination of organic compounds in each type and the relationship in the efficiency between the elimination of N and P were researched.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.2
• /
• pp.249-255
• /
• 2014

So many drinking water treatment plants are under various difficulties by new reinforced effluent standards. Since the target turbidity, much higher than annual average, for designing sludge thickener have to be set to confront high turbidity season, the sludge at thickener should be put up for a long time during usual days. So the soluble manganese and chloroform may be formed under the anaerobic environment in the sludge thickener when the sludge retention time is longer with low turbidity. This phenomenon results in difficulties to keep regulatory level of the discharged effluent. For an effort to overcome the problems, a sludge aeration was successfully implemented into the thickening process. As a result, the final effluent quality and sludge volume were much improved; 41 % of manganese, 62 % of chloroform and 35 % of sludge volume. Additionally, effluent quality was improved ; 61 % of Manganese on aeration with pH control and we could make sure of stability effluent quality despite a long sludge retention time. We recommended the standard of installation sludge aeration equipment to nationally supply water treatment plant under effluent water quality problem ; Manganese, Chloroform, etc.

• Environmental Engineering Research
• /
• v.13 no.4
• /
• pp.177-183
• /
• 2008

Ex-situ reductive dechlorination of carbon tetrachloride (CT) by iron sulfide in a batch reactor was characterized in this study. Reactor scaled-up by 3.5 L was used to investigate the effect of reductant concentration on removal efficiency and process optimization for ex-situ degradation. The experiment was conducted by using both liquid-phase and gas-phase volume at pH 8.5 in anaerobic condition. For 1 mM of initial CT concentration, the removal of the target compound was 98.9% at 6.0 g/L iron sulfide. Process optimization for ex-situ treatment was performed by checking the effect of transition metal and mixing time on synthesizing iron sulfide solution, and by determining of the regeneration time. The effect of Co(II) as transition metal was shown that the reaction rate was slightly improved but the improvement was not that outstanding. The result of determination on the regeneration time indicated that regenerating reductant capacity after $1^{st}$ treatment of target compound was needed. Due to the high removal rates of CT, ex-situ reductive dechlorination in batch reactor can be used for basic treatment for the chlorinated compounds.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.11
• /
• pp.1174-1179
• /
• 2008

Many modeling and calibration methods have been developed to analyze and design the biological wastewater treatment process. For the systematic use of activated sludge model (ASM) in a real treatment process, a most important step in this usage is a calibration which can find a key parameter set of ASM, which depends on the microorganism communities and the process conditions of the plants. In this paper, a standardized calibration protocol of the ASM model is developed. First, a weighted effluent quality index(WEQI) is suggested far a calibration protocol. Second, the most sensitive parameter set is determined by a sensitive analysis based on WEQI and then a parameter optimization method are used for a systematic calibration of key parameters. The proposed method is applied to a calibration problems of the single carbon removal process. The results of the sensitivity analysis and parameter estimation based on a WEQI shows a quite reasonable parameter set and precisely estimated parameters, which can improve the quality and the efficiency of the modeling and the prediction of ASM model. Moreover, it can be used for a calibration scheme of other biological processes, such as sequence batch reactor, anaerobic digestion process with a dedicated methodology.

• Transactions of the Korean hydrogen and new energy society
• /
• v.25 no.1
• /
• pp.11-18
• /
• 2014

This study was conducted to investigate the effect of thermal pre-treatment on bio-hydrogen from food waste. Two continuous reactors operated and VFAs(volatile fatty acids) production and microbial communities were analyzed. The average hydrogen yield was 0.50 and 0.33mol $H_2/mol$ $hexose_{added}$ in thermally treated food added reactor(R1) and control(R2), respectively. Butyrate concentration was similarly 7,500mg/L in both reactors, but two times higher lactate concentration was observed in R2(3,800mg/L). The results of FISH(fluorescence in situ hybridization) showed that the relative microorganism to hydrogen producing bacteria was 78 and 27% in R1 and R2, respectively.

• Journal of Korean Society on Water Environment
• /
• v.32 no.2
• /
• pp.191-196
• /
• 2016

This study aimed to evaluate SBR operation cycle for removing the high-concentration organic matter of distillery wastewater in the ginseng processing plant. The experiment was conducted with the use of a laboratory scale SBR reactor and distillery wastewater as the influent. The results indicated an increase in pH from 4.08 to 7.59 of distillery wastewater after aeration for 2 hours. Also, the optimum SBR operation cycle for the removal of organic matter and nitrogen was 2 hr of aeration and 6 hr of anaerobic conditions. Adjustment of proper pH through aeration time is most critical in the SBR operation for distillery wastewater treatment. In this study, we presented an efficient method for distillery wastewater treatment.

• Advances in environmental research
• /
• v.4 no.3
• /
• pp.155-172
• /
• 2015

In this study, a complete set of recirculating cooling water system and the required instruments were built in a semi-industrial-scale and a 50 g/h ozone generation plant and a chlorine system were designed for cooling water treatment. Both chlorination and ozonation treatment methods were studied and the results were analyzed during two 45-days periods. The concentrations of ozone and chlorine in recirculating water were constant at 0.1 mg/lit and 0.6 mg/lit, respectively. In ozone treatment, by increasing the concentration cycle to 33%, the total water consumption decreased by 26% while 11.5% higher energy efficiency achieved thanks to a better elimination of bio-films. In case of Carbon Steel, the corrosion rate reached to 0.012 mm/yr and 0.025 mm/yr for the ozonation and chlorination processes, respectively. Furthermore, consumptions of the anti-corrosion and anti-sedimentation materials in the ozone cooling water treatment were reduced about 60% without using any oxidant and non-oxidant biocides. No significant changes in sediment load were seen in ozonation compared to chlorination. The Chemical Oxygen Demand of the blow-down in ozonation method decreased to one-sixth of that in the chlorination method. Moreover, the soluble iron and water turbidity in the ozonation method were reduced by 97.5% and 70%, respectively. Although no anaerobic bacteria were seen in the cooling water at the proper concentration range of ozone and chlorine, the aerobic bacteria in chlorine and ozone treatment methods were 900 and 200 CFU/ml, respectively. The results showed that the payback time for the ozone treatment is about 2.6 years.

• Journal of Environmental Health Sciences
• /
• v.24 no.1
• /
• pp.62-69
• /
• 1998

It has been studied that the measurement of odor component emission at confectionery manufacture. The objects of this study were to investigate reduction of offensive odor. The survey effects of odorous materials are presented as follows. The countermeasure of operating process is to minimize sludge sediment in each unit facility. Especially, in summer, we have to clean the sludge frequently, because anaerobic decomposing is likely to occur easily. The sludge or scum from sedimentation tank pond, and floating tank should be treated quickly. We should avoid overloading operation. In the case of overloading, dissolved oxygen should be increased, the quality of wastewater input should be decreased. When dried cakes from condense tank or floating tank are left in treatment plant, we should cover, to prevent diffusion of smell with masking materials. The seasonal condition of operating should be fixed and the kind of coagulants should be changed because the wastewater in each season have different loading rates and organic materials. Odorous materials are very sensitive to the seasonal temperature variation. Especially, when the amount of rainfall is small and the high temperature of maintenance in long periods, air diffusion rate is large, so odorous materials can make great effect on surroundings comparision with other periods. To reduce odorous gas, as short term method, we had better take ceramic addition method. Especially, in summer we should take ceramic addition method. Also, as long term method, the size of wastewater treatment facility is the most important in the normal operating of wastewater treatment facility. But wastewater treatment facilities in this factory are too old, treatment process is old fashion, and the size is too small. So, large wastewater quantity to treat in summer. As results, the expansion of wastewater treatment facility and the process of improvement are required. Restriction level of odor was exceed. As it is overloaded in summer, the basis cause of odor is that the size of wastewater treatment facility is small. The prediction of air quality equilibrium density variation show that the odorous materials from working place are Amine materials whose smell strength is about 2.5(a little strong degree). We can suppose that in summer is sensitive to temperature variation, smell strength is larger as to reduce the origin of odor. We must expand wastewater treatment facility and improve the process A.S.A.P.

• Journal of Periodontal and Implant Science
• /
• v.34 no.2
• /
• pp.449-459
• /
• 2004

Bacterial byproducts and volatile sulfur compounds(VSC) have been found to be the leading intra-oral agents, specifically, the byproducts of gram negative anaerobic bacteria have been implicated as primary factors of halitosis in patients presenting with periodontal disease. The objective of this study was to determine the correlation between periodontal treatment and the subsequent reduction in the level of halitosis. Forty-three subjects presenting with periodontal disease were examined before periodontal treatment, one week after treatment, one month after treatment, and finally, two months after treatment, using a portable sulfide monitoring $Halimeter^{(R)}$ to measure the VSC concentrations at the prescribed intervals. The results of the study were as follows: 1. Significant decreases in the mean VSC concentration were observed at the one week, one month, and two month post-op intervals relative to the pre-op measurement. (p<0.05) 2. Significant decreases in the mean VSC concentration were observed in subjects after completion of flap operations. Significant decreases in the mean VSC concentration were observed at the one and two month post-flap operation measurement relative to the VSC concentration at one week (p<0.05), but no significant differences between the one month and two month VSC concentrations were found. (p<0.05) 3. Significant decreases in the mean VSC concentration were observed in subjects after completion of subgingival curettage (p<0,05). Significant decreases were found between the one week and one month measurements and between the one month and two month measurements, but significant differences were not observed between the one week and two month measurements. (p<0.05) The results of this study show significant decreases in VSC concentration in test subjects after periodontal treatment. It can be inferred from the results above, that periodontal disease is a significant contributing factor of halitosis, and that treatment of periodontal disease can been an effective means of reducing VSC concentration in patients presenting with halitosis concurrent with periodontal disease.