• 한국환경보건학회지
• /
• 제26권4호
• /
• pp.9-14
• /
• 2000

In this study, the removal efficiencies of organics, nitrogens and phosphorus from municipal wastewater using $A^2$/O process were investigated. BO $D_{5}$ removal efficiencies were indicated 95% and 94% with HRT of 12 hr and 10 hr, respectively. CO $D_{Cr}$ average removal efficiency and concentration of effluent were indicated 87% and 34mg/$\ell$. SS average removal efficiency and concentration of effluent were indicated 93% and 4~17mg/$\ell$. T-N removal efficiency and concentration of effluent were shown as 60~80% and below 15mg/$\ell$. In aerobic basin, removal efficiency of N $H_4$-N was shown over 97% with N $H_4$-N volume load 0.16kg N $H_4$-N/㎥.d and in anoxic basin, denitrification efficiency was indicated over 80% with return sludge rate 0.5Q and internal recirculation rate 2.5Q. Removal efficiency and effluent concentration of phosphorus were shown over 80% and below 2 mg/$\ell$ with return sludge rate 0.5Q.Q.

• 한국환경복원기술학회지
• /
• 제8권1호
• /
• pp.45-51
• /
• 2005

Total phosphorus(TP) removal was examined in a surface-flow wetland constructed in April 2003 during its initial operating stage from June to November 2003. Its dimensions were 87mL by 14mW. It was a part of a four-wetland-cell treatment system constructed near the Kohung Estuarine Lake located in the southern part of Korea. Effluent from a night soil treatment plant was discharged into the wetland and purified effluent from the wetland was discharged into Sinyang Stream flowing into the Lake. Cattails(Typha angustifolia ) from natural wetlands were cut at about 40 cm height and transplanted into the wetland. An average of 25.0$m^3$/day of effluent flowed from the plant into the wetland. Water depth was maintained about 0.2m and hydraulic detention time was about 5.2 days. Average heights of the cattail stems in June and October 2003 were 47.2 and 164.6cm, respectively. The average number of stems was 10.2 stems/$m^2$ in June 2003 and 18.8 stems/$m^2$ in October 2003. Average temperature of influent and effluent ranged 23.4 and $24.2^{\circ}C$, respectively. The average TP concentrations of influent and effluent were about 1.31, 0.50mg/L, respectively. TP loading rate of influent into the wetland averaged 26.81mg/$m^2$, day and average TP loading rate of effluent was 10.04mg/$m^2$, day. Monthly average TP removal by the wetland during the warm growing season of cattails(June to September) ranged 16.28~19.57mg/$m^2$, day and during the cold senescent period (October to November) ranged 12.62~13.90mg/$m^2$, day. TP removal in the wetland continued during the cold winter months and was primarily done by sedimentation and precipitation of phosphorus rather than phosphorus absorption by cattails and microorganisms.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 동계학술발표대회 논문집
• /
• pp.434-440
• /
• 2007

The Effluent ground water overflows in deep and broad ground space building. Temperature of effluent ground water is in 12$\sim$18$^{\circ}C$ annually and the quality of that water is as good as living water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effuent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and close type heat pump system using effluent ground water was installed and tested for a church building with large and deep ground space. The effluent flow rate of this building is 800$\sim$1000 ton/day. The heat pump capacity is 5RT each. The heat pump system heating COP was 3.0$\sim$3.3 for the open type and 3.3$\sim$3.8 for the close type system. The heat pump system cooling COP is 3.2$\sim$4.5 for the open type and 3.8$\sim$4.2 for close type system. This performance is up to that of BHE type ground source heat pump.

• 한국환경농학회지
• /
• 제23권4호
• /
• pp.234-239
• /
• 2004

[ $NO_3$ ]-N and T-N removal rates of cattail wetland cells were compared with those of reed wetland cells. The examined cells were a part of a pond-wetland system composed of two ponds in series and six wetland cells in parallel. Each wetland cell was 25m in length and 6m in width. Cattails (Typha angustifolia) were transplanted into three cells and reeds Phragmites australis) into another three ones in June 2000. Water of Sinyang stream flowing into Kohung Estuarine lake located in the southern part of the Korean Peninsula was pumped into the primary pond, its effluent was discharged into the secondary pond Effluent from the secondary pond was funneled into each cell. Two cattail and reed cells were chosen for this research. Water quantity and quality of influnt and effluent were analyzed front May 2001 through October 2001. The volume of influent and effluent of the cells averaged about $20.0\;m^3/day$ and $19.3\;m^3/day$, respectively. Hydraulic retention time was approximately 1.5 days. Influent $NO_3$-N concentration for the four cells averaged 2.39 mg/L. Effluent $NO_3$-N concentration far the cattail and reed cells averaged 1.74 and 1.78 mg/L, respectively. Average $NO_3$-N retention rate for the cattail and reed cells by mass was 30 and 29%, respectively. Influent T-N concentration far the four cells averaged 4.13 mg/L. Effluent T-N concentration for the cattail and reed cells averaged 2.55 and 2.61 mgL respectively. Average T-N retention rate for the cattail and reed cells by mass was 39 and 38%, respectively. $NO_3$-N and T-N concentrations in effluent from the cattail cells were significantly low (p=0.04), compared with those from the reed cells. Cattail wetland cells were more efficient for $NO_3$-N and T-N abatement than reed ones.

• 한국환경보건학회지
• /
• 제24권1호
• /
• pp.132-140
• /
• 1998

회전원판공정(rotating biological contactorRBC)과 화학적 처리공정을 결합한 처리시스템을 이용하여 도시하수내 포함된 유기물과 영양염류를 제거할 경우에 수리학적 부하 (hydraulic loading)와 처리수 반송율 (recirculation rate)의 시스템 처리효율에 미치는 영향을 알아보고자 하였다. 각각의 수리학적 부하 0.031, 0.0535 및 0.076 $m^3/m^2/d에서 반송율을 100%, 200%, 300%로 변화시켰고, 질산화에 필요한 알카리도의 보충 및 화학적 처리를 위하여 lime(CaCO$_3$)을 가하여 유입수의 pH를 10.4-11.0으로 유지시켰다. 실험결과 수리학적 부하 0.0535 $m^3/m^2/d에서 BOD, COD의 제거효율이 가장 높게 나타났으며, 질산화 효율 및 질소 제거효율에서는 수리학작 부하 0.035 $m^3/m^2/d, 반송율 300%에서 가장 높았으며, 반송율별에서는 수리학적 부하를 고려할 때 300% 반송하는 것이 가장 높은 유기물 제거효율을 보였다. 반송율과 수리학적 부하를 증가시킬 경우에 발생되는 슬러지내 유기물 함량은 점점 증가하였고, 수리학적 부하 0.076 $m^3/m^2/d, 반송율 300%일 경우에는 유기물 함량이 47%로 매우 높았다. 이는 부하증가에 따른 미생물 성장의 증가와 더불어 수리학적 부하 증가에 따른 전단력의 증가가 영향을 미쳤기 때문이다. 인을 제거하기 위하여 pH를 10.4-11.0으로 유지시킨 경우에 인을 90%이상 제거할 수 있었으며, 유출수내 평균 SS농도는 40 mg/l를 상회하였다.

• Journal of Electrochemical Science and Technology
• /
• 제12권2호
• /
• pp.266-271
• /
• 2021

A commercial PbO₂ electrode was adopted as the anode for the electrochemical degradation of the real textile effluent with the initial COD of 56.0 mg L^-1 and the stainless steel plate as the cathode. The effect of the initial pH, the electrolyte flow rate and the cell voltage on the COD, the current efficiency and the energy consumption were investigated without the addition of NaCl or Na₂SO₄. The experimental results illustrated that the PbO₂ electrode can reduce the COD of the textile effluent from 56.0 mg L^-1 to 26.0 mg L^-1 with the current efficiency of 86.1% and the energy consumption of 17.5 kWh kg^-1 (per kilogram of degraded COD) under the optimal operating conditions. Therefore PbO₂ electrode as the anode was promising to further electrochemically degrade the real textile effluent.

• 한국물환경학회지
• /
• 제23권1호
• /
• pp.12-18
• /
• 2007

Difference of total coliforms (TC) survival time of mixed samples (effluent were mixed by seawater or freshwater) were examined in various conditions. The time taken to achieve a 90% reduction in the TC concentration ($T_{90}$) of effluent, high initial TC concentration and low initial TC concentration samples indicated 143.9, 121.9 and 89.6 hours at $25^{\circ}C$, respectively. At $4^{\circ}C$, log removal rate after 336 hours were 0.96, 1.04, and 1.30. TC survival time of effluent-inoculated seawater sample was longer than that of effluent-inoculated freshwater sample in laboratory. At outdoor condition, TC inactivation curves of effluent-inoculated seawater or freshwater samples showed similar patterns. And both of them were greatly influenced by climate condition. There was not enough evidence that TC survived longer in freshwater than sea water. It was unlikely that the salinity of sea water contributed to the inactivation process of TC.

• 한국환경복원기술학회지
• /
• 제7권5호
• /
• pp.100-106
• /
• 2004

$NO^3$-N removal was examined from July 2002 to December 2002 of a surface-flow constructed treatment wetland cell, which was a part of a treatment wetland system composed of four wetland cells and one distribution pond. The system was established on rice paddy near the Kohung Estuarine Lake located at the southern part of the Korean Peninsula. The lake and the paddy were formed by a salt marsh reclamation project. Effluent from a secondary-level treatment plant was funneled into the system. The investigated cell was created in June 2002. Its dimensions were 87 m in length and 14 m in width. It had an open water zone at its center, which was equivalent to 10 percent of its total area. Reeds(Phragmites australis) were transplanted from natural wetlands into the cell and their stems were cut at about 40 cm height from their bottom ends. Average 25 $m^3$/day of effluent from the plant was funneled into the cell by gravity flow and average 24.2$m^3$/day of its treated effluent was discharged into the Sinyang Stream flowing into the lake. Its water depth was maintained about 0.2 m and its hydraulic detention time averaged 5.2 days. The average height of the reed stems was 45.2 cm in July 2002 and 80.5 cm in September 2002. The number of stems averaged 40.3 stems/$m^2$ in July 2002 and 74.5 stems/$m^2$ in September 2002. The reeds were established initially well. $NO_3$-N loading rate of influent and effluent averaged 173.7 and $93.5mg/m2{\cdot}day$, respectively. Removal of $NO_3$-N averaged $80.2mg/m2{\cdot}day$ and its removal rate by mass was about 50 %. Considering the initial operation of the cell and the inclusion of the cold months of November and December in the analysis period, the $NO_3$-N removal rate was good.

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

• 한국농공학회지
• /
• 제42권4호
• /
• pp.96-105
• /
• 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.