• Journal of Korean Society on Water Environment
• /
• v.31 no.4
• /
• pp.418-427
• /
• 2015

This study was carried out to evaluate the performance of a lab-scale novel septic tank system for improving the conventional septic tank in the developing countries of water shortages. The lab-scale novel septic tank system consists of sepetic tank, aeration tank with HBC-ring, and sand filter. Optimum HRT was reguired about 1.5days to get a total COD removal efficiency of 90%, COD, BOD and SS removal efficiency was about 70%, 60%, and 85% in sepetic tank only. The structure of sepetic tank with two stages results in the high removal efficiency of organic matter. When sepetic tank, aeration tank, and sand filter were more than HRT 1.5days, 18hrs, and 12hrs, respectively, final effluent was less than 20 mg/L of BOD, 14 mg/L of SS, so that there is a high potential of its use for reusing water in flush toilet. There is no significant effect of HRT change on nutrient removal. Total nitrogen removal efficiency was about 40%, final effluent was 30~40 mg/L of TN, total phosphorus removal efficiency was about 11~25%, final effluent was 9~12 mg/L of TP. Because there is very small amounts of organic nitrogen and phosphorus in effluent, it was possible to reuse water for agricultural use.

• Journal of Environmental Science International
• /
• v.6 no.4
• /
• pp.409-415
• /
• 1997

In order to Investigate the possibility as a simple technique of wastewater treatment for recirculating aquaculture system, the experiment by a biofilter unfit was carried out. The high and stable removal efficiency of nitrogen could be obtained by selecting the optimum recycle ratio and DO concentration. It was found that the proper combination of nitrifacation and denitrfication step in the reactor would be required for increasing the removal efficiency. The extent of nitrogen removal gradually decreased UO the rise of re- cycle ratio since the depression of denitrificatlon by the lack of hydrogen donor. The depression of nitrogen removal was overcome by increasing the CIN ratio In the wastewater. The extent of phosphorus removal was increased slightly with the increase of DO concentration and recycle ratio, but high removal efficiency was not observed. However, the extent of COD removal was not affected by recycle ratio and DO concentration and showed the stable removal of above 90%.

• Journal of Korean Society on Water Environment
• /
• v.25 no.1
• /
• pp.18-25
• /
• 2009

Nitrogen removal and methane production from piggery wastewater were investigated in two-phase anaerobic digestion (TPAD) coupled with biological nitrogen removal (BNR) process at $35^{\circ}C$. Methane production rate was about $0.7L/L{\cdot}day$ at organic loading rate (OLR) of $1.2g{\cdot}TCOD/L{\cdot}day$ in methanogenic UASB. Conversion efficiency of the removed TCOD into methane in UASB was as high as 72% and overall TCOD removal efficiency in this system was over 97%. Ammonia nitrogen were stably removed in BNR system and overall efficiency were 98%. With recirculation of the nitrified final effluent to TPAD, nitrogen oxides were completely removed by anaerobic denitrification in the acidogenic reactor, which did not inhibit the acidogenic activities. Overall TN removal efficiency in the TPAD-BNR system was as high as 94%.

• Journal of Environmental Health Sciences
• /
• v.19 no.3
• /
• pp.36-40
• /
• 1993

The objective of this research was to retrofit an on-site sewage treatment system suitable to current situation of Korea to reduce the pollution loading and preserve the invaluable water resources. Operation at the F/M ratio of 0.1 kg. BOD/kg MLSS day showed 87.1% BOD removal efficiency and 84.5% COD removal efficiency, and its effluent concentration was 6.4 mg/l as BOD and 21.7 mg/l as COD. Average removal of total nitrogen showed high removal efficiency of 80%.

• Journal of Animal Environmental Science
• /
• v.6 no.2
• /
• pp.65-72
• /
• 2000

This study was conducted to investigate the effects of artificial filaments equipped in the aeration tank of aerobic·fermentation system on the removal efficiency of swine wastes which were fermented an aerobically and thus containing high nitrogen. Two aerobic fermentation system each consist4s of 4 tanks ; storage tank, 1st and 2nd aeration tank and settling tank were run before and one or three weeks after equipment of artificial filament in the aeration tanks. Total solids concentration tended to increase by aerobic fermentation in all running periods. However, decreased(P<0.05) total nitrogen concentration was shown three weeks after the equipment of artificial filament. Ammonia nitrogen concentration also largely decreased(p<0.05) in both running periods of one and three weeks after equipment of artificial filaments. These results suggest that the artificial filaments may improve the removal efficiency of nitrogen in swine wastewater containing high nitrogen during aerobic fermentation.

• Journal of environmental and Sanitary engineering
• /
• v.5 no.2
• /
• pp.45-52
• /
• 1990

This study is to discuss limiting factors influenced on the removal efficiency of organic materials investigated using the polypropyrene biofilter which appropriate to attach micro-organism in order to apply the contact oxidation proce,:5. The results obtained in the experiment were as follows : 1. In the range o: pH 4.0~ 12.0 was obtained the removal efficiency of COD higher than 85% It was proved that variation of pH(4.0 ~ 12.0) was nothing to do with the removal efficiency of substrate in continuous reactor. 2. Temperature to obtain removal efficiency of COD higher than 85% was $10^{\circ}$ ~$40^{\circ}$. Removal efficiency of COD was no less than those at high temperature if MLVSS concentration was maintained 8,000~ 15,000 m/1. 3. In the continuous reactor, the volumetric loading of COD for removal efficiency higher than 95% had to be 0.5~1.5 kg COD/.d below. And then the HRT was Bhrs. 4. In comparison with the conventional activate sludge process, the contact oxidation process was excellent in removal efficiency, sludge production rate and maintenance.

• Journal of Korean Society on Water Environment
• /
• v.25 no.5
• /
• pp.727-734
• /
• 2009

This study was carried out to evaluate the high rate biological reactor such as lab scale reactor before the application in site, and to get the basic data for possibility using liquid fertilizer with the effluent from biological reactor when the centrifugal machine was applied. The total volume of this reactor in 6 L, in composted of anoxic reactor (2 L), aerobic reactor (2 L), and nitification reactor (2 L). BOD removal efficiency rates when centrifugal machine was applied after effluent from biological reactor are over than 95%. This biological reactor was required post process to satisfy the effluent standards, and was need centrifugal machine to control the washout of microbes in the reactor. T-N removal efficiency rate in HRT 24 hr with centrifugation is 80.0%, and it is desirable to operate less than $1.3kgN/m^3{\cdot}d$ for 70% of T-N removal efficiency rate. T-P removal efficiency rate in HRT 24 hr is 68.2%, and become higher 71.3% after centrifugation. Considering in the 28.6% T-N removal efficiency rate, the nitrogen contents of the effluent from reactor is 0.34% to satisfy the liquid fertilizer.

• Journal of Korean Society of Water and Wastewater
• /
• v.13 no.4
• /
• pp.27-34
• /
• 1999

An experimental study on improvement of the paper-mill wastewater treatment using the pure oxygen activated sludge process was conducted. The effects of hydraulic retention time(HRT) and BOD loading on organic removal efficiency were investigated. The BOD removal efficiencies were above 90% under all examined HRTs except for HRT of 3 hours. The increase of HRT from 3 hours to 6 hours, and to 12 hours significantly improved BOD and COD removal efficiencies, respectively. However, additional increase of HRT did not affect organic removal efficiency. F/M ratio change at fixed HRT did not affect organic removal efficiency. However, F/M ratio investigated in this study(0.11~1.98kgBOD/kgMLVSS/day) was 5 times greater in maximum than that of conventional activated sludge process, which implies that pure oxygen activated sludge process can treat wastewater with high organic strength. Under the same HRT, the volumetric BOD loading change cause no effect on organic removal efficiency also.

• Journal of Korean Society of Water and Wastewater
• /
• v.14 no.1
• /
• pp.62-75
• /
• 2000

Most of biological treatment to remove contaminants in municipal wastewater have been conducted by activated sludge process. But, the process have several probIems such as enormous site needed for construction of treatment facilities, unstable treatment due to limited ability to control load fluctuation, frequent sludge bulking and appearance of lots of surplus sludge. In this study, the experiments were performed through submerging biofilm of PEPP media in existing aeration tank with raw water from municipal wastewater treatment plant and then submerging PVDC and PEPP media, different from shape and chemical peculiarity in anoxic reactor. Throughout the experience, nutrient removal efficiency according to HRT, nitrogen phosphorous removal efficiency, behavior of nitrogen and dewatering efficiency have been compared and analysed with those of activated sludge process. As the results, BOD removal efficiency according to BOD volumetric load and F/M ratio was not found any differency in two processes, but was decreased below 90% as going along the condition of high load in activated sludge process. Kinetic coefficient was $K_{max}=1.162day^{-1}$, $K_s=53.77mg/L$, $Y=0.166mgVSS/mgBOD_{rem}$. and $K_d=0.019day^{-1}$. It was found that the removal efficiency, even though in aerobic condition, in biofilm process equipped anoxic reactor was higher than the one in activated sludge process within the range of 70~80%, and became better as HRT increased. Phosphorous removal efficiency was not found any differency in two processes. In biofilm process, treament efficiency even in conditions of high load was not decreased, because the biomass concentration could be maintained in high condition compared with activated sludge process. As HRT increased, suspended and attached biomass was increased and the other hand, F/M ratio was decreased as biomass' increasing. Biomass thickness was increased. from $10.43{\mu}m$ to $10.55{\mu}m$ as HRT increased and density of biomass within $40.79{\sim}41.16mg/cm^2$. The results also present that the dewatering efficiency of sludge generated in biofilm process was higher than in activated sludge process, and became better as HRT increased.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.6
• /
• pp.755-760
• /
• 1999

To remove nitrogen oxides(NOx) in exhaust gas of diesel engine three-way catalytic process with plasma discharger has great possibilities. Characteristics of NOx removal depends on NO conver-sion to $NO_2$ and /or $HNO_3$ due to high activation energies for NO oxidation and reduction, NOx removal efficiency by using three-way catalytic with plasma discharger indicated about 50% at 40watt power consumption condition.