염철민 Cheol Min Yeom

DOI: Vol.20(No.5) 391-396, 2004

이지현 Jee Hyun Lee , 최지용 Ji Yong Choi , 박석순 Seok Soon Park

DOI: Vol.20(No.5) 397-408, 2004

Due to the growing impact of non-point source pollution and limitation of water treatment technology, a new policy of water quality management, called a source protection, is now becoming more important in drinking water supply. The source protection means that the public agency purchases the pollution sensitive area, such as riparian zone, and prohibit locations of point and non-point sources. Many studies have reported that this new policy is more economical in drinking water supply than the conventional one. However, it is very difficult to determine location and size of the pollution sensitive zone in the watershed. In this paper. we presented the scientific criteria for the priority of the pollution sensitive zone, along with a case study of the upstream watershed of the Paldang Reservoir, Han River. This study includes applications of the analytical hierarchy process(AHP) and a watershed-based land prioritization(WLP) model. After major criteria affecting water quality were selected, the AHP and geographic analysis were performed. The WLP model allowed us to include both quantity and quality criteria, using AHP as the multi-criteria method in making decision and reflecting local characteristics and various needs. By adding a travel-time function, which represents the prototype effectively, the results secured adaptability and scientific objectivity as well. As such, the WLP model appeared to provide reasonable criteria in determining the prioritization of land acquisition. If the tested data are used with a validated travel-time and AHP method is applied after further discussion among experts in such field, highly reliable results can be obtained.

Source protection, WLP model, AHP method, Land acquisition, Prioritization drinking water supply, Watershed management

김충환 Chung Hwan Kim , 김학철 Hak Chul Kim , 김한승 Han Seung Kim , 김범수 Berm Soo Kim , 안효원 Hyo Won Ahn

DOI: Vol.20(No.5) 409-414, 2004

Pilot-scale experiments were performed for the treatment of bank filtrate containing high manganese concentration around 2 ㎎/L using rapid manganese sand filtration to investigate effects of oxidant dose and pH control on the removal efficiency of manganese. For theoretical dose ranges of oxidant (sodium hypochlorite) between 3 and 4 ㎎/L, the manganese concentration of effluent was 0.57 ㎎/L, which corresponded to 72.5% removal and was higher than drinking water quality standards of 0.3 ㎎/L. For excess dose ranges of oxidant between 4 and 8 ㎎/L, the manganese concentration of effluent was reduced to 0.14 ㎎/L, which corresponded to 94.5% removal, but the residual chlorine concentration was over 1.0 ㎎/L. On the other hand, manganese removal efficiency drastically increased up to the value of 98.0%, which is equivalent to the effluent concentration of 0.03 ㎎/L by controling pH to the range between 7 and 8 for the theoretical dose of oxidant. Consequently, these results indicated that appropriate dose of chemicals, such as oxidant and alkali, and continuous monitoring of manganese should be necessary to obtain efficient removal of manganese and to optimize the maintenance of treatment facilities for the treatment of bank filtrate with high concentration of manganese.

Bank filtration, Manganese removal, Manganese sand, Chlorination, pH control

김이형 Lee Hyung Kim , 강주현 Joo Hyon Kang

DOI: Vol.20(No.5) 415-421, 2004

Litter wastes on highway runoff are gradually being considered one of the major pollutants of concern in protecting the integrity of receiving waters for beneficial use. The California State Water Resources Control Board has identified in their 303(d) list at least 36 water bodies where trash or litter is considered a pollutant of concern. The first TMDL adopted by the Region 4 (Los Angeles area) of the California State Water Quality Control Board was for trash in the Los Angeles River. The first flush characteristic study was developed to obtain first flush water quality and litter data from representative stormwater runoff from standard highway drainage outfalls in the Los Angeles area. Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over two years. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. The event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. Event mean concentrations were ranged 0.0021 to 0.259 g/L for wet gross pollutants and 0.0001 to 0.027 g/L for wet litters. The first flush phenomenon was evaluated and the impacts of various parameters such as rainfall intensity, drainage area, peak flow rate, and antecedent dry period on litter volume and loading rates were evaluated. First flush phenomenon was generally observed for litter concentrations, but was not apparent with litter mass loading rates. Litter volume and loading rates appear to be directly related to peak storm intensity, antecedent dry days and total flow volume.

EMC, First flush, Highways, Litter, Los Angeles, Nonpoint source

정팔진 Paul Gene Chung , 고홍석 Hong Seok Goh , 현미희 Mi Hee Hyun , 이은주 Eun Ju Lee

DOI: Vol.20(No.5) 422-431, 2004

Water quality modeling was performed for the purpose of diagnosis and prediction of water quality in Gyoung Choen reservoir, using EUTRO5/WASP Build model. WASP Builder is capable of visual display in window and it has an advantage of updating and modification for data. Field data of 1992, Spring, Summer, and Fall, were used to calibrate model and these results were validated using data of 2000, Spring, Summer, and Fall. The reservoir was divided into 4 epilimnion segments. Water quality system for modeling were consist of BOD, Chlorophyll-a, DO, NH₃-N, NO₃-N, T-N, PO₄-P. T-P. The results of water quality modelling using EUTRO5/WASP Builder, a range of the Correlation for calibration of BOD, T-N, T-P, and Chlorophyll-a according to three seasons are 0.63~0.90, 0.81~0.97, 0.75~0.98, and 0.77~0.98 respectively. And the correlation between simulated and observed values for verification of BOD, T-N, T-P, and Chlorophyll-a according to three seasons are 0.93. 0.94, 0.81, and 0.80 respectively. Among the pollutant sources for a basin of the Gyoung Choen reservoir, generated amount of livestock is the highest and BOD, T-N, T-P of generated loading percentage are 94%, 81%, and 95%. So, we suppose that inflow load amount will decrease 50% and increase 50% only livestock about current load amount. If increasing load amount of livestock 50% in segment 2 and 3, BOD, T-N, and T-P simulated increasing to range of 0.02~0.15㎎/ℓ, 0.029~0.08㎎/ℓ, 0.011~0.029㎎/ℓ in comparison with current water quality

Gyoung Choen reservoir, WASP5, WASP Builder, Calibration, Verification

정용 Yong Chung , 백영석 Young Seog Beck , 권동식 Dong Sik Kwon , 이기공 Ki Gong Lee , 강형석 Hyeong Seok Kang

DOI: Vol.20(No.5) 432-436, 2004

The principle and methodology of risk assessment was applied to establish the quality standard of potential impurities of drinking water treatment chemicals. The impurities(arsenic, lead, cadmium, chromium, mercury, etc.) are regulated as the contained quantity of chemicals in Korea while they are regulated as the quality standard with the idea of 10% of the national safety drinking water standard in U.S.A(NSF) and Japan(JWWA). According to risk assessment of the current standard implemented in Korea, the excess cancer risk of arsenic and lead were determined in around 10^(-5) and the hazard quotient(HQ) of cadmium and chromium were below 10^(-2), respectively. And the standard concentration of the impurities are regulated as much as 2%~6% of the national drinking water quality standard. The values are more enforced rather than the standards in U.S.A(NSF) and Japan(JWWA) regulating the concentration of impurities the 10% of the national drinking water quality standard. We conclude that the impurities standard of drinking water treatment chemicals should be reconsidered comprehensively concerning the national safety drinking water quality standard and risk assessment.

Risk assessment, Impurities, Excess cancer risk, Hazard quotient, HQ, Drinking water treatment chemicals

박현건 Hyun Geoun Park , 이춘식 Chun Sik Lee , 이홍재 Hong Jae Lee , 서동철 Dong Cheol Seo , 허종수 Jong Soo Heo

DOI: Vol.20(No.5) 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.

Natural purification, Sewage treatment, Nitrogen removal, Phosphorous removal

김우항 Woo Hang Kim , Okada Mitsumasa

DOI: Vol.20(No.5) 447-451, 2004

The various pretreatment processes were evaluated to remove organic pollutants of weathered oil contaminated seawater(WOCS) for reverse osmosis desalination process. Biodegradation, coagulation, ultrafiltration, advanced oxidation processes and granular activated carbon filtration were used to evaluate the potential of organic pollutants removal in WOCS. Dissolved Organic Carbon(DOC) was almost not removed by biodegradation in WOCS. DOC` was removed by 25% and 10% with the addition of FeCl₃ and PAC in WOCS, respectively. The removal efficiency using ultrafiltration(WOCS 500) was about 20% of DOC and 40% of E_(260), respectively. In AOP application of WOCS, the removal of organic materials was improved up to 60% by the combination of UV/O₃ compared to UV process. However, 98% of DOC in WOCS could be removed by granular activated carbon filtration. It is revealed that activated carbon filtration is the best process for the pretratment of DOC removal.

Desalination, Reverse osmosis, Pretreatment, Pollutants

이선미 Sun Mi Lee , 조훈제 Hun Je Jo , 김정규 Jeong Gyu Kim , 정진호 Jin Ho Jung

DOI: Vol.20(No.5) 452-456, 2004

Gamma-rays effectively decomposed TPA and EG, thus removal of 1.0×10^(-3)M pollutants was near 65 and 95%, respectively, at an absorbed dose of 10 kGy. However, TOC removal in the radiation treatment was less than 5% due to a low transformation of both TPA and EG to CO₂. For TPA, gamma-ray treatment largely reduced biodegradability(BOD_5/COD) by degrading TPA to non-biodegradable organic acids. This implies that the change of biodegradability should be considered when the radiation treatment is combined with conventional biological techniques. A weight-loss wastewater containing TPA and EG was also purified by gamma-ray treatment. Extraordinarily, biodegradability of the wastewater was increased at a low dose of 1 kGy. Though underlying mechanism was not clearly identified, this result stresses the effect of wastewater composition and absorbed dose on the biodegradability change.

Gamma-rays, Terephthalic acid, Ethylene glycol, Biodegradability, Weight-loss wastewater

박운지 Woon Ji Park , 이해승 Hae Seung Lee , 이찬기 Chan Ki Lee , 김성근 Sung Gun Kim

DOI: Vol.20(No.5) 457-465, 2004

The objective of this study is to evaluate the possibility to apply the Moving Bed Biofilm Reactor(MBBR) in the activated sludge treatment process with existing aerobic HRT. Optimal operation conditions were assumed according to the analysis of organic matter and nutrients removal efficiencies depending on loading variations. The process was operated under different conditions: RUN Ⅰ(HRT=7.14hr, I·R=100%), RUN Ⅱ(HRT=6.22hr, I·R=100%), RUN Ⅲ(HRT=6.22 hr, I·R=l 50%), RUN Ⅳ(HRT=6.22hr, I·R=200%), the TBOD removal efficien Gies are 88%, 88.5%, 94.6%, 97.6%, respectively. Overall TSS removal efficiency is 90%, and it is increasing in RUN Ⅳ. In the case of Nitrogen, the highest removal efficiency of 90% was observed in RUN Ⅲ and RUN Ⅳ, Nitrification and Denitrification rates are 0.013-0.016 ㎏ NH₃-N/㎏ Mv-d and 0.009-0.019 ㎏ NO₃/㎏ My-d, respectively. Phosphorus removal efficiencies are 89.6% in RUN Ⅰ, 91.5% in RUN Ⅱ, 84.3% in RUN Ⅲ, and 76.4% in RUN Ⅳ. The process under shorter SRT yields better performance in terms of phosphorus removal. It was noticed that to achieve the effluent phosphorus concentration of less than 1 ㎎/L and removal efficiency higher than 80%, SRT should not be longer than 10 days. Experimental result shows that HRT of 6.22 hours is suitable for this treatment process, and, as a result, the aerobic reactor including moving media and DO depletion tank have a sufficient effect to the process performance.

Moving Bed Biofilm Reactor, MBBR, Hydraulic Retention Time, HRT, Nitrification rate, Denitrification rate, Internal Recycle, I,R

김이태 I Tae Kim , 배우근 Woo Keun Bae , 김우정 Woo Jeong Kim

DOI: Vol.20(No.5) 466-472, 2004

Red mud is formed as a waste during bauxite refining known as Bayer`s process. Its main constituents are iron, aluminium, sodium and silica. The disposal of large quantities of wasted red mud causes a serious ecological problem. In this study, the red mud wasted from the bauxite refinery was studied for phosphate removal from aqueous solution according to activation methods. The influence of heat treatment, and neutralization with sea water and acid treatment level for the optimum conditions for phosphate removal have been determined. Heat treatment combined with acid treatment is most suitable for the removal of phosphate from aqueous solution. The optimal condition was activated with 1N HCl solution after heating in 600℃ during 4 hours. Acid and heat treatment causes sodalite compounds which hinder the phosphate adsorption to leach out. The adsorption data obtained followed a first-order rate expression and fitted well with the Freundlich Isotherm well.

Activation of red mud, Phosphate, Removal

장정렬 Jeong Ryeol Jang , 최선화 Sun Hwa Choi , 권순국 Soon Kuk Kwun

DOI: Vol.20(No.5) 473-479, 2004

A sedimentation basin (SB) at the inlet of an irrigation reservoir which was constructed using an auxiliary dam was monitored to evaluate its pollutant removal efficiency. Water sampling at three points, i.e., inflow stream, upstream and downstream of the reservoir, were taken 5 times before and after the construction of the SB in 1999 and 2003, respectively. No significant water quality variations in inflow stream were observed during these periods. The COD, T-N, T-P and SS removal efficiencies were 38, 24, 35 and 49%, respectively. The results indicated that those removal efficiencies significantly increased during the rainy season and COD removal efficiency, especially, was higher than others studies. The scale of SB in this study was rational as aspects of pollutant removal efficiency and hydraulic detention time. And it is recommended that SB, at inlet of an reservoir, should be constructed as completely separated structure from reservoir water body and having SAR Index from 0.7% to 1.0%.

Sedimentation basin, Irrigation reservoir, Pollutant removal efficiency, Surface to area ratio index

김이태 I Tae Kim , 이희자 Hee Ja Lee , 배우근 Woo Keun Bae

DOI: Vol.20(No.5) 480-487, 2004

This study was conducted to find the effect of electron acceptors on the formation of granular sludge by using four different types of electron acceptors. The phosphorous uptake, denitrification, and sulfate reduction in anoxic modes were simultaneously occured because of the presence of the polyphosphate accumultating organism(PAO) that utilize nitrate and sulfate as an electron acceptor in the anoxic zone. Denitrifying phosphorous removal bacteria(DPB) was enriched under anaerobic/anoxic/aerobic condition with a nitrate as an electron acceptor, and desulfating phosphorous removal bacteria(DSPB) was enriched under anaerobic/anoxic/aerobic condition with a sulfate as an electron acceptor. Polyphosphate accumulating organism(PAO) were enriched in the anaerobic/aerobic SBR. PAO took up acetate faster than DPB and DSPB during the aerobic phase. The sludge with nitrate and sulfate as an electron acceptors grew as a granules which possessed high activity and good settleability. In the anaerobic/aerobic modes, typical floccular growth was observed. In the result of bench-scale experiment, simultaneous reactions of phosphorus uptake, denitrification and sulfate reduction were observed under anoxic condition with nitrate and sulfate as an electron acceptors. These results demonstrated that the anaerobic/anoxic modes with nitrate and sulfate as an electron acceptors played an important role in the formation of the sludge granulation.

Sequencing batch reactor, SBR, Polyphosphate accumultating organism, PAO, Denitrifying phosphorous removal bacteria, DPB, Electron acceptors

신인수 In Soo Shin , 최봉종 Bong Jong Choi , 이승목 Seung Mok Lee

DOI: Vol.20(No.5) 488-493, 2004

The effects were examined from several conditions of TiO₂ photocatalysis reaction to phenols degradation by changing its reacting conditions such as phenol concentration, pH, TiO₂ concentration, H₂O₂ concentration, flow rate, and intensity of ultraviolet rays. Phenol degradation was more efficient in low concentration of phenol, neutral pH. Phenol degradation appeared to increase as concentration of TiO₂ photocatalyst, that of H₂O₂ and intensity of ultraviolet rays increased. As TiO₂ dosage increased, initial rate constant k linearly increased. When H₂O₂ was injected more than optimum, phenol removal rate didn`t increase in proportional to the change of H₂O₂ concentration as OH radicals was being consumed. When flow rate is less than 4.75 m³/m²?day, phenol removal efficiency appeared to decrease as ultraviolet rays transmission rate becomes low by TiO₂ suspension coated in photo reaction column. Meanwhile, initial rate constant according to light intensity change in less than 25mW/㎠ appeared to be in proportion to light intensity (mW/㎠). Removal efficiency decreased about 12% after 180 minutes of reaction time while showed stable removal efficiency of 100% after 300 minutes when using regenerated TiO₂.

Photocatalysis, Chemical oxidation, UV, TiO2, Phenol, Wastewater treatment

김석구 Seog Ku Kim , 김영임 Young Im Kim , 윤상린 Sang Leen Yun , 이용재 Yong Jae Lee , 김이호 Ree Ho Kim , 김종오 Jong Oh Kim

DOI: Vol.20(No.5) 494-499, 2004

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Therefore, it is necessary to manage both point and non-point sources contaminations for protecting water environment and improving water quality. This study investigated the characteristics of pollutant release over a wide range of rainfall intensities as a requisite to control road runoff that accounts for the largest portion of non-point source contamination in urban areas. Samples of runoff rainwater collected from real road surfaces were analyzed for physicochemical parameters such as pH, suspended solids, and heavy metals. A experimental model road (30cm×30cm) was also used to evaluate wash-off properties of pollutants deposited on the surface as functions of time and rainfall intensity. Analysis of runoff samples on rain events showed that the pollutant wash-off patterns for heavy metal and suspended solids were similar. This implies that the particles in rainwater adsorb heavy metals. Experiments using the model road made of impervious asphalt demonstrate a strong first flush phenomenon. At high rainfall intensity, approximately 80% of total pollutants were released within 15 min. The pollutant wash-off rates rapidly increase from 9 ㎜/hr to 12 ㎜/hr of rainfall intensity and decrease over 12 ㎜/hr of rainfall intensity.

First rainfall, Road runoff, Rain intensity, First flush effect

김석구 Seog Gu Kim , 윤상린 Sang Leen Yun , 김영임 Young Im Kim , 이용재 Yong Jae Lee , 김이호 Ree Ho Kim , 김종오 Jong Oh Kim

DOI: Vol.20(No.5) 500-505, 2004

While more attention has been paid in recent years to urban point source pollution control, no considerable measures have been taken to control urban non-point source pollution. Contaminants from non-point sources deposited on urban impermeable surfaces such as road and highway are easily released to the public waters by rainfall, leading to the deterioration in water quality in urban area. The present study investigated a system using filter media to reduce the level of contamination in urban road runoff. Three different media, designated as J-P (polypropylene, blowing type), B-P (polypropylene, fiber type), and P-F (Polyvinyl alcohol, cube and sheet type) were evaluated on the basis of pollutant removal efficiency as well as hydraulic property. Experiments were peformed using a 1/4-scale treatment unit at various pollutant roading and rainfall intensity with real rainwater runoff collected from road surfaces. The results at different rainfall intensities shows that the medium J-P is superior to the other media for water permeability. J-P was not blocked at 10 ㎜/hr rainfall and its permeability was stable. On the other hand, B-P and P-F resulted in substantial overflow ratio even at l ㎜/hr rainfall intensity. Comparing treatment efficiencies for suspended solids, all media showed similar removal ranged from 91% to 95%. However, J-P seems to be better than the other media considering its higher water permeability. J-P and P-F, both hydrophobic, yielded over 76% of heavy metal removal. But, the hydrophilic media B-P showed much smaller removal ranging from 26% to 47%. This indicates that J-P and P-F are beneficial to remove heavy metal due to their hydrophobic property. The treatment efficiencies over PAHs (poly aromatic hydrocarbons) showed the similar removal efficiency ranging from 66% to 97% for all three media.

Point source, Non-point source, Rainfall, Hydraulics special, PAHs

김윤중 Yun Jung Kim , 박은혜 Eun Hye Park , 김규동 Gyu Dong Kim , 남경필 Kyoung Phile Nam , 정태학 Tai Hak Chung

DOI: Vol.20(No.5) 506-511, 2004

Maintaining dissolved oxygen (DO) at sufficiently low concentration in the aeration tank at a wastewater treatment plant (WWTP) is essential for reduction of the costs of operation and maintenance. On the other hand, the low DO level may result in adverse effect on the integrity of the activated sludge. A typical and disastrous outcome frequently experienced is the outgrowth of filamentous microorganisms, which is called as filamentous bulking. In addition to the traditional methods such as sludge settleability and microscopic observation of the culture, molecular techniques including polymerase chain reaction (PCR) amplification followed by 16S rRNA sequencing were applied to identify filamentous bacteria present in bulking sludge under a condition of low DO concentration. Two morphologically distinct groups, presumably consisting of Sphaerotilus natans, and Eikelboom Type 1701 or Type 1851, were identified through microscopic observation. They were further confirmed by subsequent 16S rRNA sequencing. Dominant filamentous bacteria identified by the molecular techniques were consisted of three major groups. Sequences of partial 16S rRNA cloned showed that the filamentous bulking organisms were closely related to Eikelboom Type 021N and Eikelboom Type 1701, and Sphaerotilus natans, respectively. Molecular methods were found to possess a strong potential of direct examination of the microbial community of an activated sludge system.

DO, Filamentous bulking, 16S rRNA, Sphaerotilus natans, Eikelboom-type species

조현희 Hyun Hee Cho , 박재우 Jae Woo Park

DOI: Vol.20(No.5) 512-519, 2004

Hybrid barriers using reduction and immobilization were tested to remediate the groundwater contaminated with multi-pollutants in this study. Iron filings and HDTMA(hexadecyltrimethylammonium)-bentonite were simulated in columns to assess the performance of hybrid barriers for remediation of trichloroethylene(TCE)-contaminated water. TCE reduction rate for the mixture of iron filings and HDTMA-bentonite was about 7 times higher than that for iron filings, only suggesting the reduction of TCE was accelerated when HDTMA-bentonite was mixed with iron filings. TCE reduction rate for the two layers of iron and HDTMA-bentonite was nearly similar to that for iron filings alone, but the partition coefficient(Kd) for the two layers was 4.5 times higher than for that iron filings only. TCE was immobilized in the first layer with HDTMA-bentonite, and then dechlorinated in the second layer with iron filings. HDTMA-bentonite may contribute to the increase in TCE concentration on iron surface so that more TCE can be reduced. Also, TCE removal in the hybrid barriers was not affected by chromate and naphthalene while the reduction rate of TCE with the co-existing contaminants by iron filings was significantly decreased. Significant TCE removal in this research indicates that the proposed hybrid barrier system has the potential to become the effective remediation alternative during the occurrence of oil shock. Also, if subsurface environments are contaminated with multi-pollutants that contain non-reducible compounds as well as reducible compounds such as TCE, the conventional reactive barriers cannot be applied to this subsurface environment. while the proposed hybrid system can be applied successfully.

Reduction, Sorption, Trichloroethylene, Iron filings, HDTMA-bentonite, Chromate, Naphthalene

이선화 Sun Hwa Lee , 김동수 Dong Su Kim

DOI: Vol.20(No.5) 520-524, 2004

As a feasibility study for the application of carbon nanotubes to the treatment of environmental pollutants, the adsorption characteristics of humic acid on carbon nanotubes has been investigated. The dispersion features of carbon nanotubes in aquatic environment were investigated by measuring the variation of their electrokinetic potentials with pH, and the effects of some dispersants on their dispersion features were also examined. Under the experimental conditions, humic acid was observed to mostly adsorb on nanotubes within a few minutes and reach the equilibrium state within about one hour. The adsorption features of humic acid on nanotubes were found to follow the Freundlich model better than the Langmuir Model. Humic acid adsorbed on carbon nanotubes endothermically and the change of enthalpy in adsorption reaction was estimated to be ca. 18.37 kJ/mol at standard state. The entropic change in adsorption reaction for humic acid was ca. 0.0503 kJ/mol at standard state and the activation energy for adsorption was also estimated based on the change of rate constants with temperature. FT-IR investigations showed that the functional groups such as alcohol, ester, and aromatics existing in the chemical structure of humic acid might work as the bridge in its adsorption on nanotubes.

Humic acid, Carbon nanotubes, Adsorption, Dispersion, Kinetics

노성덕 Sung Duk Roh , 이대근 Dae Keun Lee , 전양근 Yang Kun Chun

DOI: Vol.20(No.5) 525-533, 2004

The object of this study was to test for STORMSYS process that composed Catch Basin and Stormsys(three units: vortex solids separator, filter media bed and vegetated filter strips). It could be applied to treat the first-flush non-point pollution materials on the road(especially, motorway). This study investigated that the runoff characteristics of non-point pollutions containing the heavy metal(Fe, Zn and Cu) by rainfall showed relatively high pollution concentration in the early-stage storm runoff on the road, which seems to be caused by the vehicular traffic, and showed the rapid reduction of pollution concentration on the basis of about 5mm rainfall volume. As the number of the non-rainy days were increased, the pollution concentration by storm runoff was increased, also. As a test result of this process, the average removal efficiency of BOD, COD_(mn), SS, T-N and T-P over the testing period were 92.7%, 88.6%, 97.4%, 93.0% and 93.3%, respectively. Also, the average removal efficiency of n-Hexane, Fe, Zn and Cu were 86.7%, 96.1%, 84.4% and 78.4%, respectively. As shown in the characteristics of storm runoff, the non-point pollution materials have high pollution concentration in the early-stage storm runoff on the road, the installation of STORMSYS process is expected to reduce considerable amount of non-point pollutions.

Catch Basin, Non-point pollution materials, Storm runoff, STORMSYS process

윤주환 Zu Whan Yun , 장희란 Hee Ran Jang , 한종훈 Jong Hun Han , 한혜정 Hye Jung Han

DOI: Vol.20(No.5) 534-538, 2004

Granulation characteristics have been studied with an aerobic sequencing batch reactor(SBR). Organic loading of 2.46 ㎏ COD/m³/day followed by 4.14 kg COD/m³/day had been applied to the lab-scale SBR with a very short settling time during the operating cycle. The granulation proceeded to the diameter range of 3 to 5 mm with MLSS concentration of 12,000 ㎎/L at 45th days of operation while COD removal efficiency remained almost consistent after the granule formation. It has been noticed that aerobic granulation under the higher loading with a very short settling time seemed to be due to the microbial selection of better flocculating species.

Aerobic granular sludge, Granulation, SBR