• 한국환경과학회지
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• 제15권5호
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• pp.439-446
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• 2006

The effluent discharge standards of industrial wastewater has become more stringent since 2003. Many industrial wastewater treatment plants has been upgraded to advanced treatment facilities. There are high concentrations of nitrate(>200 mg/L) and ammonium(>50 mg/L) nitrogen in the acrylic fiber wastewater of H textile Co. Wastewater from acrylic fiber industry containing acrylonitrile, which may affect the subsequent biological treatment process. Manufacturing of acrylic fiber also produces shock loadings. Excessive acrylonitrile and polymer debris produced in the polymerization process was screened, coagulated with CaO and settled down. A preaeration system was added to treat this high pH effluent to remove volatile organic compound and ammonia nitrogen by the air stripping effect. it was found that nitrification rate was not sufficient in the Anoxic/Oxic(AO) process. One denitrification tank was converted to nitrification reactor to extend HRT of nitrification. Nitrification rate of ammonia nitrogen was promoted from 32% to 67% by this modification and effluent nitrogen concentration was well satisfied with the effluent standards since then.

• 한국산학기술학회논문지
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• 제14권1호
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• pp.493-498
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• 2013

합성 고분자 화합물의 생산과 ethanolamine(ETA, 원자력발전소에서 사용하는 pH 조절제)는 수질을 오염시키는 폐수를 발생한다. 본 연구는 유기물에 의해 유발된 COD를 감소시키기 위한 물리 화학적 처리법과 처리 약품을 개발하였다. $FeCl_2$와 $MgCl_2$를 1/1로 혼합하여 혼합응집제를 사용함이 COD 제거효율이 가장 좋은 결과를 얻었다. 유기물을 함유한 폐수처리에 복합응집제를 주입함으로써 COD제거율이 80%이상으로 나타났다.

• 상하수도학회지
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• 제9권2호
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• pp.77-83
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• 1995

The effluent from conventional nightsoil treatment plants contains nutrients, color and chlorides, in addition to residual organics and suspended solids, and thereby causes substantial pollution problems in receving water resources. In order to verify the usefullness of electrolysis in removing those residual pollutants from such conventional nightsoil treatment plant effluent, a bench scale experiment was conducted using sufficiently dilluted human nightsoil as experiment feeds. The result showed mean removals of 45% of total phosphorus and 85% of color, in addition 87% of residual BOD, 47% of residual COD and 85% of residual SS. The optimum electric current was found to be 15 ampere and the optimum hydraulic residence time 21/2 hour.

• 산업기술연구
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• 제18권
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• pp.1-6
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• 1998

This study was conducted to use disused vinyl as biofilm for biological sewage treatment. Efficiency verification was performed on laboratory and on-site plant. In laboratory study, total biochemical oxygen demand(TBOD) removal rate was ranged 94.8~97 % in each hydraulic retention tim(HRT), 12, 16, 20, 24 hr, respectively. At that time, filling rate was 50 %. And effluent TBOD concentration was low ranged 3.64~6.28 mg/L. In on-site plant, TBOD removal rate was ranged 88.2~96.8 % and effluent TBOD concentration was 4.8~17.7mg/L. This concentration was lower than disign effluent concentration, 30mg/L. Total kjeldhal nitrogen(TKN) removal efficiency was ranged 56.8~90.9%. This was resulted higher than Lab. scale treatment efficiency.

• 상하수도학회지
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• 제14권1호
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• pp.84-98
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• 2000

Control of Trihalomethanes(THMs) is a major concern of many water treatment plants. A number of researchers have studied the effectiveness of activated carbon adsorption process in removing THMs or organic halogen compounds. Recently, attention has been paid to the biological activated carbon (BAC) treatment of THM precursors as an alternative to the carbon adsorption treatment because of its effectiveness as well as its low running cost. In this study, changes of THM formation potential(THMFP) and removal of substrates in the SBR effluent were investigated in an attempt to clarify the mechanisms of the decrease/increase of THMFP in the BAC treatment. The increase and decrease of THMFP concentrations were observed in effluents during prolonged operation. When PCP or DBS was feeded as substrate contained in SBR effluent, the THMFPs were easyly removed with TOCs removal. But the case of SBR effluent containing SDS or glycine was introduced, and when microbial growth came to its near steady state, the THMFPs of treated effluents were increased more or less in comparison to those in the influents. Such increases of THMFP coincided with the increase in microbial growth within the activated carbon fiber(ACF) column. In the case of only sucrose was feeded as substrate on ACF colume, THMFP concentrations of effluent were higher than those of influent. The THMFP concentration was significantly increased on inlet part of ACF column, which biomass inhabits abundantly, then they were decreased gradually. These increases mean production of the secondary THM precursors by biological activities, which can be removed by adsorption and biological degradation on ACF column.

• 한국물환경학회지
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• 제20권5호
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• pp.437-446
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• 2004

To develop sewage treatment apparatus by natural purification method, the sewage treatment plant that consisted of aerobic and anaerobic plot was constructed. And then, the effects of treatment conditions on the removal of pollutants in the relation to sewage loading, sewage injection method and season according to the pebble kind. Removal rate of BOD and COD according to the sewage loading in effluent were over 95 and 77%, respectively. Removal rate of nitrogen in treated water by aerobic plot and effluent using sand were about 22~40 and 49~75%, respectively. Those of effluent using sand 75%+ oyster shell 25% and sand 50%+ oyster shell 50% as filter media in comparison with using sand were about 7~25 and 16~23%, respectively. Removal rate of phosphorus in treated water by aerobic plot and effluent using sand as filter media were about 30~36 and 52~56%, respectively. Those of effluent using sand 75%+ oyster shell 25% and sand 50%+ oyster shell 50% in comparison with using sand as filter media were about 11~40 and 12~45%, respectively. Removal efficiency of BOD and COD according to the intermittent injection method of sewage were slightly decreased, but those of nitrogen and phosphorus were little varied in comparison with continuous injection method. Removal efficiency of BOD and COD in winter in comparison with the others were little varied, but those of nitrogen and phosphorus slightly decreased.

• 한국물환경학회지
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• 제37권1호
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• pp.20-31
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• 2021

In this study, an analysis of the characteristics of organic matter and nitrogenous oxygen demand (NOD) of 17 sewage effluent and wastewater treatments was conducted. High CODMn and carbonaceous biological oxygen demand (CBOD) concentrations were observed in the livestock treatment plants (LTP), wastewater treatment plants(WTP), and night soil treatment plants (NTP), but the highest NOD concentration and contribution rates of NOD to BOD5 were found in sewage treatment plants (STP). There was no significant difference in the CBOD/CODMn ratio for each of the six pollution source groups, but the LTPs, WTPs, and NTPs all showed relatively high CODMn concentrations in their effluent samples, indicating that they are facilities which discharge large amounts of refractory organic matter. The seasonal change of NOD in all facilities' effluent was found to be larger than the seasonal change of CBOD, and data results also revealed an elevation of NOD and NH3-N concentration from December to February, when the water temperature was low. There was no significant difference in NH3-N concentration in relation to pollution source group (p=0.08, one-way ANOVA), but the STP, which had a high NOD contribution rate to BOD5 of 48%, showed a high correlation between BOD5 and NOD (r2=0.95, p<0.0001). These results suggest that the effect of NOD on BOD5 is an important factor to be considered when analyzing STP effluent.

• 한국물환경학회지
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• 제21권2호
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• pp.158-168
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• 2005

In this study, the discharging effluents from have been 9 municipal wastewater treatment plants surveyed for 1 year-period. Statistics including probability distribution, cumulative occurrence concentration and other statistical parameters were presented. In addition, treatment performance and its stability were also discussed. Most of the plants, have an operational problem of high soluble organic content in the secondary effluent which may be associated with the integrated treatment of human and livestock manures. Nitrogen concentration in the effluents were usually higher during the period of summer and winter. It was found that this is mainly due to lack of the proper C/N ratio during the summer, or/and the effects of low temperature and less dilution by dry weather during the winter. Phosphorus concentration is sharply increased in June. Discussion with plant operators told that it is due to the dissolution of phosphate from the sludge accumulated in the primary settling tanks from the early spring to june. During this period, usually, sludge treatment line is highly overloaded with flush-outs of the sediments also stored in the bottom of combined sewer due to the low flow during winter season. Most of the plants can meet new effluent discharge limits of the nitrogen and phosphorus, and total coliform without further treatment.

• 한국물환경학회지
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• 제22권5호
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• pp.905-912
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• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• 한국농공학회지
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• 제42권4호
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• pp.96-105
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• 2000

Field experiment was performed from August 1996 to December 1999 to examine the performance of constructed wetland system for wastewater treatment in rural area. The constructed wetland system was installed in Konkuk University and the effluent from septic tank of school building was used as an influent to the treatment basin. The treatment basin was composed of sand bed with planted reed. From August 1996 to June 1998 the hydraulic loading rate was fixed with about 15.63cm/day and theoretical detention time was 1.38 days, and from July 1998 to December 1999 the hydraulic loading rate was about 6.25cm/day and theoretical detention time was 3.5days. It worked continuously even during winter time, and the sewage flowed without freezing even when average daily air temperature was below -1$0^{\circ}C$. Average removal rate of BOD , COD, and SS was about 70%, T-P removal rate was about 50.8% , and T-N removal rate was 23.9%. The reason for poor T-N removal might be due to high influent concentration and short retention times. At the later years BOD and COD removal rates were increased , and SS and T-P removal rates did not change significantly , but T-N removal rates were decreased. The effluent of the wetland system often effluent water quality standards for sewage treatment plant, therefore, further treatment would be required if the effluent need to be discharged to the public water. Wetland system involves relatively large land area and could be suitable for rural area. Therefore, utilization of reclaimed sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal of sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal of sewage in rural area.