• 한국환경농학회지
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• 제22권4호
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• pp.251-254
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• 2003

Phosphorous removal rate and emergent plant growth were examined of a surface-flow constructed treatment wetland system, whose dimensions were 31 meter in length and 12 meter in width. The system was established on floodplain in the down reach of the Kwangju Stream in Korea in one and half months from May to June 2001. Cattails(Typha angustiflora) were transplanted in the system. They were dug out of natural wetlands and stems were cut at about 40 cm height from their bottom ends. Water of the Kwangju Stream were funneled into it via a pipe by gravity flow and its effluent were discharged back into it. The stems of cattails grew from 45.2 cm in July 2001 up to 186 cm in September 2001 and the number of cattail stems per square meter increased from 22 in July 2001 to 53 in September 2001. The early establishment of cattails was good. Volume and water quality of inflow and outflow were analyzed from July 2001 through December 2001. Inflow averaged $40\;m^3/day$ and hydraulic retention time was about 1.5 days. The concentration of total phosphorous in influent and effluent was 0.85 mg/L, 0.41 mg/L, respectively. The average removal rate of total phosphorous in the system was about 52%. The retention efficiency was slightly lower, compared with that in surface-flow wetlands operating in North America, whose retention efficiency was reported to be about 57%. The lower abatement rate could result from the initial stage of the system and inclusion of two cold months into the six-month monitoring period. Root rhizosphere in wetland soils and litter-soil layers on bottoms were not properly developed. Increase of standing density of cattails within a few years will establish both root zones and substrates beneficial to the removal of phosphorous, which may lead to increase of the phosphorous retention rate. The system was submerged one time by heavy storm during the monitoring period. The inundation, however, scarcely disturb its environment.

• 대한환경공학회지
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• 제34권5호
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• pp.326-334
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• 2012

본 연구는 최근 수 환경에서의 과불화화합물의 배출원 중 하나로 인식되고 있는 폐수처리장을 대상으로 이들 물질의 처리 공정별 물질량 흐름 및 거동을 예측하고자 수행되었다. 시료채취는 여름철과 겨울철에 유입수, 중화조유출수, 1차침전지 유출수, 포기조 유출수, 2차 침전지 유출수, 최종 방류수, 탈수여액, 1차 슬러지, 농축슬러지, 탈수 슬러지를 각각 3일간 채취하였으며, 채취한 후 동일한 비율로 혼합하여 분석용 시료로 하였다. 총 10개 물질을 대상물질로 하여 분석한 결과, 물 시료 중 농도는 PFOS (perfluorooctanesulfonate)가 N.D.~26.29 ng/L, PFOA (perfluorooctanoate)가 N.D.~38.15 ng/L로 검출되었으며 기타 PFNA (Perfluorononanoate)가 N.D.~36.79 ng/L, PFHxS (perfluorohexanesulfonate)가 N.D.~24.36 ng/L로 나타났다. 슬러지 시료의 경우, PFOS가 6.82~59.37 ng/g, PFOA가 0.13~0.37 ng/g, PFDS (perfluorodecanesulfonate)가 N.D.~0.83 ng/g으로 검출되었다. 각 처리 공정별 물질량 흐름을 관찰한 결과, 과불화화합물의 대부분이 유입되는 양보다 유출되는 양이 더 많은 것으로 나타났는데 이는 전구물질들이 처리공정을 거치면서 생물학적 분해에 의해 과불화화합물의 발생원으로서 작용하고 있기 때문인 것으로 판단된다.

• 한국물환경학회지
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• 제26권3호
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• pp.377-386
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• 2010

Introduction of TBELs into Korean environmental regulatory system for wastewater may require very careful considerations and appropriate modifications of the TBELs applied in US. The Korean regulations for wastewater are based on uniform regulatory criteria for wastewater effluent discharge and are quite different from the individual permit system in US. In addition, the toxic pollutants regulated in Korea are much less than those in US. Therefore, the effects of TBELs application on the pollutants reduction and the economic feasibility should be carefully assessed for different categories of wastewater sources. In this study, the applicability of TBELs for the industrial categories of Korea was discussed. The TBELs were derived for a sample category, the pulp paper paperboard manufacture, based on the previously reported analytical data from 52 facilities of the domestic pulp paper paperboard manufacture in Korea. It was suggested that the BAT effluent limitations were BOD 30 mg/L, $COD_{Mn}$ 40 mg/L, SS 40 mg/L, T-N 30 mg/L and T-P 4 mg/L and that the allowable effluent loads were $0.31{\sim}1.75kgCOD_{Mn}/ton$-products. Due to the limitation of insufficient data, there were difficult to obtain the important factors to derive more systematic and accurate limitation standards for the pollutants such as the 'Long Term Average (LTA)', the 'Product Normalized Discharge Flow (PNDF)', and the 'Variability Factor (VF)'. However, as the first trial of TBELs determination based on the all available analytical data reported, the procedure and the outcome of the study may provide valuable insight on application of TBELs in Korea.

• 한국환경복원기술학회지
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• 제4권4호
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• pp.64-71
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• 2001

Treatment efficiency was examined of a pond-wetland system constructed for water quality conservation of Koheung Estuarine Lake over one year after its establishment in July 2000. The system is composed of primary and secondary ponds in series and six wetland cells in parallel. Cattails (Typha angustiflora) were planted in three wetland cells and common reeds (Phragmites australis) in three other cells. Water pumped from Sinyang Stream flowing into the Lake was funneled into primary pond whose effluent was discharged into secondary pond by gravity flow. Effluent from secondary pond was distributed into each wetland cell. SS, $BOD_5$, T-N, and T-P concentrations in influent to primary pond, and effluent from primary pond, secondary pond, and three wetland cells planted with cattails were analyzed for about one year from August 2000 to August 2001. The removal rates at primary pond for SS, $BOD_5$, T-N and T-P were 29%, 30%, 15%, and 36%, respectively. The abatement rates at secondary pond for SS, $BOD_5$, T-N and T-P were 38%, 40%, 30%, and 47%, respectively. The reduction rates measured at three cattail-planted wetland cells for SS, $BOD_5$, T-N and T-P were 54%, 57%, 60%, and 68%, respectively. Considering early stage of the pond-wetland system and inclusion of winter during the research period, its treatment efficiency was rather good. Cattails had not yet grown to dense stands due to initial establishment period, which resulted in slightly lower treatment efficiencies of wetland cells for these pollutants, compared with those of ponds.

• 한국농공학회지
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• 제44권5호
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• pp.96-105
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• 2002

As an useful water purification system for non-point source pollution in rural watersheds, interests in constructed wetlands are growing at home and abroad. It is well known that constructed wetlands are easily installed, no special managemental needs, and more flexible at fluctuating influent loads. They have a capacity for purification against nutrient materials such as phosphorus and nitrogen causing eutrophication of lentic water bodies. The Constructed Wetland Design Model (CWDM), developed through this study is consisted mainly of Database System, Runoff-discharge Prediction Submodel, Water Quality Prediction Submodel, and Area Assessment Submodel. The Database System includes data of watershed, discharge, water quality, pollution source, and design factors for the constructed wetland. It supplies data when predicting water quality and calculating the required areas of constructed wetlands. For the assessment of design flow, the GWLF (Generalized Watershed Loading Function) is used, and for water quality prediction in streams estimating influent pollutant load, Water Quality Prediction Submodel, that is a submodel of DSS-WQMRA model developed by previous works is amended. The calculation of the required areas of constructed wetlands is achieved using effluent target concentrations and area calculation equations that developed from the monitoring results in the United States. The CWDM is applied to Bokha watershed to appraise its application by assessing design flow and predicting water quality. Its application is performed through two calculations: one is to achieve each target effluent concentrations of BOD, SS, T-N and T-P, the other is to achieve overall target effluent concentrations. To prove the validity of the model, a comparison of unit removal rates between the calculated one from this study and the monitoring result from existing wetlands in Korea, Japan and United States was made. As a result, the CWDM could be very useful design tool for the constructed wetland in rural watersheds and for the non-point source pollution management.

• 한국환경과학회지
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• 제15권10호
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• pp.945-949
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• 2006

For a membrane bio-reactor, it is possible to fillet and separate activated sludge and effluent by head loss of centimeters, if non-woven fabric material is used as titration media. However, if non-woven fabric material is used to thicken high-concentration sludge, excessive sludge attachment causes the rapid decrease of flux. Mesh with fore sizes of $100{\mu}m,\;150{\mu}m,\;and\;200{\mu}m$ allows for easy separation of attached sludge. This study examined the possibility of mesh as filtration media. Existing close-flow filtration process, which requires maintaining sludge movement, makes It difficult to obtain high thickening rate. With a view of complementing this weakness, this study has made an experimental examination on how high-concentration sludge (about 3,000mg/L to 10,000mg/L) will be filtered and thickened when mesh module is submersed in the bio-reactor. Effluent flowed from the bottom of the bio-reactor by head loss of 65cm. In case of pore size of $100{\mu}m$, SS showed high recovery of 80% to 96%; therefore, it has been decided that mesh can be used as filtration media. Filtration lasted for more than 9 hours, until sludge with 9,000mg/L in MLSS concentration was thickened 9 times as dense. In the range from 3,610mg/L to 9,060mg/L in MLSS concentration, it was possible to obtain effluent with less than 2mg/L in MLSS concentration within 10 minutes.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.236-241
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• 2005

A decolorization process using ion exchange chromatography was developed to refine rhEGF as a cosmetic ingredient. A macroreticular resin (D314) was selected, with respect to its high decolorization rate and recovery yield of rhEGF, and the operational conditions of the decolorization process optimized. The optimum conditions were as follows: the rhEGF effluent was ion exchanged at a flow rate of 60.0mL/h, with an effluent pH 5.0, using a chromatographic column (i.d. 16mm) packed with D314, with a 7.5cm in bed height. The decolorization process was carried out under the optimum conditions, and halted when the effluent volume reached 350mL, giving a decolorization rate and recovery yield of rhEGF higher than 67 and $80\%$, respectively. When the decolorization rate exceeded $67\%$, the final product turned out to be white or light yellowish, which was to the satisfaction of the cosmetic standard.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.85.2-93
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• 2000

A demand of marine outfall system have been much increased for the effective disposal of the wastewater due to population and industrial development at the coastal areas. The outfall system discharges primary or secondary treated effluent into coastline or at the deep water, or between these two. The discharge is carried out by constructing a pipeline on the sea bed with a diffuser or with a tunnel, risers and appropriate. The effluent, which has a density similar to that of fresh water, rises to the sea surface forming plume or jet, together with entraining the surrounding salt water and becomes very dilute. Thus there have been growing interests about plume behaviour around the outfall system. Plume or jet discharged from single-port or multi-port diffuser might cause certain impacts on coastal environment. Near field mixing characteristics of discharged water field using CORMIX model with has been studied for effective outfall design various conditions on ambient current, depth, flow rate, effluent concentration, diffuser specification, port specification etc.. This kind of analysis is necessary to deal with water quality problems caused by the ocean discharge. The analyzed vesult was applied to the Pusan Jungang dffluent outfall system plan.

• 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.

• Korean Chemical Engineering Research
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• 제57권4호
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• pp.469-474
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• 2019

Fermentation of palm oil mill effluent (POME) produces biohydrogen in a mixture at a specific set condition. This research was conducted to purify the produced mixed biohydrogen via absorption and membrane techniques. Three different solvents, methyl ethanolamine (MEA), ammonia ($NH_3$) and potassium hydroxide (KOH) solutions, were used in absorption technique. The highest $H_2$ purity was found using 1M MEA solution with 5.0 ml/s feed mixed gas flow rate at 60 minutes absorption time. Meanwhile, the purified biohydrogen using a polysulfone membrane had the highest $H_2$ purity at 2~3 bar operating pressure. Upon testing with proton exchange membrane fuel cell (PEMFC), the highest current and power produced at 100% $H_2$ were 1.66 A and 8.1 W, while the lowest were produced at 50/50 vol% $H_2/CO_2$ (0.32 A and 0.49 W). These results proved that both purification techniques have significant potential for $H_2$ purification efficiency.