류제하 Je Ha Ryu , 윤춘경 Chun Gyeong Yoon , 최재호 Jae Ho Choi , 이한필 Han Pil Rhee , 황문영 Mun Yuong Hwang , 양희정 Hwee Jung Yang

DOI: Vol.29(No.3) 309-316, 2013

Event mean concentration, Land uses, Non-point source pollution, Rainfall Level

Event mean concentration, Land uses, Non-point source pollution, Rainfall Level

서경애 Kyung Ae Seo , 정수정 Soo Jung Jung , 박종환 Jong Hwan Park , 황경섭 Kyoung Seop Hwang , 임병진 Byung Jin Lim

DOI: Vol.29(No.3) 317-328, 2013

The purpose of this study was to investigate the change of phytoplankton fluctuation and long term of water quality of Lake Juam and to evaluate the relationship between phytoplankton pattern and environmental factors data. Correlation and factor analyses were employed to identify key environmental factors affecting phytoplankton dynamics. Of 18 parameters, pH, temperature, COD, BOD and T-P were highly correlated with Chl-a. Phytoplankton data showed that cyanobacteria were dominant, and more than 60% of total algae density. Also Lake Juam received a lot of influence of the Asian monsoon climate. This study presents necessity of multivariate statistic techniques for evaluation of Lake Juam complex data set with a view to get better information data and effective management of water source.

Cyanobacteria, Factor analysis, Multivariate analysis, Phytoplankton, Principal component analysis

윤순욱 Soou Uk Yoon , 안창민 Chang Min Ahn , 김창균 Chang Gyun Kim

DOI: Vol.29(No.3) 329-336, 2013

This study was conducted to reduce excess sludge generation by recycling of return sludge to the aeration tank after solubilization by electric field charger and ultrasonifier. The return sludge was purposely broken-up to the ratio of SCODCr / TCODCr at 0.1, 0.2, and 0.3, which was tested along with control (i.e., untreated). Solubilized sludge was subsequently treated in a bench-scaled conventional activated sludge reactor. According to varying SCODCr / TCODCr ratios, TSS in the reactor was correspondingly increased from 129 to 219 mg/L and TCODCr was also from 257 to 335 mg/L. However, TSS in the effluent was nevertheless kept lower at below 30 mg/L and TCODCr was also unvaryingly below 40 mg/L. For SCODCr / TCODCr = 0.3, the amount of excess sludge produced was at the highest decreased up to as high as 78%.

Activated sludge process, Electric field, Return sludge, Sludge solubilization, Ultrasound

신상희 Sang Hee Shin , 전현숙 Hyun Sook Jeon , 이찬형 Chan Hyung Lee , 배기수 Gi Soo Bae

DOI: Vol.29(No.3) 337-342, 2013

The particle counter compared with the turbidimeter provides good precision and sensitivity and can get the characteristics of particulates effectively. The purpose of this study is to provide the application of particle counter in sand and activated carbon filters. The particle count by size could be more easily sense when the water quality is changed by the influent of high turbidity or algae. We could decide the optimal backwashing cycles and detect the efficiencies of filters by monitoring the total particle count of effluent in sand and activated carbon filters.

Activated carbon filter, Application of particle counter, Optimal backwashing cycle, Sand filter

박준대 Jun Dae Park , 오승영 Seung Young Oh

DOI: Vol.29(No.3) 343-353, 2013

Flow duration curve (FDC) can be developed by linking the daily flow data of stream flow monitoring network to 8-day interval flow data of the unit watersheds for the management of Total Maximum Daily Loads. This study investigated the applicable method for the development of long term FDC with the selection of the stream flow reference sites, and suggested the development of the FDC in 4 river basins. Out of 142 unit watersheds in 4 river basins, 107 unit watersheds were shown to estimate daily flow data for the unit watersheds from 2006 to 2010. Short term FDC could be developed in 64 unit watersheds (45%) and long term FDC in 43 unit watersheds (30%), while other 35 unit watersheds (25%) were revealed to have difficulties in the development of FDC itself. Limits in the development of the long term FDC includes no stream monitoring sites in certain unit watersheds, short duration of stream flow data set and missing data by abnormal water level measurements on the stream flow monitoring sites. To improve these limits, it is necessary to install new monitoring sites in the required areas, to keep up continuous monitoring and make normal water level observations on the stream flow monitoring sites, and to build up a special management system to enhance data reliability. The development of long term FDC for the unit watersheds can be established appropriately with the normal and durable measurement on the selected reference sites in the stream flow monitoring network.

Long term flow duration curve, Stream flow monitoring network, Stream flow reference sites, Total Maximum Daily Loads, Unit watersheds

김영윤 Young Ryun Kim , 김상단 Sang Dan Kim , 이석모 Suk Mo Lee , 성기준 Ki Jun Sung , 송교욱 Kyo Ook Song , 손민호 Min Ho Son

DOI: Vol.29(No.3) 354-364, 2013

The performance of the stormwater wetlands can be significantly influenced by antecedent stormwater in storage at the commencement of a stormevent. As inflows are intermittent and stochastic in nature, the evaluation of the treatment efficiency of a stormwater wetland should be considered by runoff capture and water treatment characteristics during interevent periods. In this study, analytical probabilistic model is applied to identity runoff capture rate and treatment efficiency of the stormwater wetland. To achieve this, continuous rainfall data recorded in Busan for 31 years has been analyzed to derive the runoff capture rate, and 1st order kinetic decay constants (kv, 1/d) are calculated from regression analysis to identify pollutants removal during interevent periods. The results show that about 60.9% of annual average runoff is captured through the stormwater wetland. The annual average treatment efficiencies of SS, BOD, COD, TN and TP is about 11.4, 8.9, 9.8, 4.3 and 9.6%, respectively. The analytical model has been compared with the numerical model and it shows that analytical model is valid. Performance evaluation methods developed in this study has the advantages of considering characteristics of rainfall-runoff, facility type and pollutant removal.

Anaytical probabilistic model, k-C model, Non-point pollution control, Stormwater capture, Stormwater wetland performance

이지원 Ji Won Lee , 금동혁 Dong Hyuk Kum , 김범철 Bom Chul Kim , 김영석 Young Sug Kim , 정교철 Gyo Cheol Jeong , 김기성 Ki Sung Kim , 최중대 Joong Dae Choi , 임경재 Kyoung Jae Lim

DOI: Vol.29(No.3) 365-376, 2013

The purpose of this study was to evaluate effects of spatio-temporal changes in land uses and rainfall magnitude using the Soil and Water Assessment Tool (SWAT). Prior of application of the model to real-world problem, the model should be calibrated and validated properly. In most modeling approaches, the validation process is done assuming no significant changes occurring at the study watershed between calibration and validation periods, which is not proper assumption for agricultural watersheds. If simulated results obtained with calibrated parameters match observed data with higher accuracy for validation period, this does not always mean the simulated result represents rainfall-runoff, pollutant generation and transport mechanism for validation period because temporal and spatial variables and rainfall magnitude are often not the same. In this study SWAT was applied to Mandae study watershed in Korea to evaluate effects of spatio-temporal changes in landuses using 2009 and 2010 crop data for each field at the watershed. The Nash-Sutcliffe model efficiency (NSE) values for calibration and validation with either 2009 or 2010 was evaluated and the NSE value for calibration with 2009 and calibration with 2010 were compared. It was found that if there is substantial change in land use and rainfall, model calibration period should be determined to reflect those changes. Through these approaches, inherent limitation of the SWAT, which does not consider changes in land uses over the simulation period, was investigated. Also, Effects of changes in rainfall magnitude during calibration process were analyzed.

Calibration, Mandae, Sediment, Spatio-temporal, SWAT model, Validation

박홍근 Hong Keun Park

DOI: Vol.29(No.3) 377-382, 2013

Enriching anammox bacteria (AMX) in a lab-scale granular sequencing batch reactor using local digester centrate, we observed the significant enrichment of the filamentous-like bacterial population. These bacteria were revealed as novel bacterial species (termed CHL) belonging to Chlorobi/Bacteroidetes phyla via Denaturing Gradient Gel Electrophoresis (DGGE). Further, niche differentiation of AMX and CHL quantification was observed in granule and filament biomass, suggesting AMX was dominant in the granule and CHL was dominant in the filament. Therefore, it was confirmed the structural role of CHL was indeed to aid the granule formation of the AMX. In parallel, the physiological role of CHL was suspected to degrade biopolymers in the digester centrate using nitrate as an electron acceptor.

Anaerobic ammonium-oxidizing bacteria, Bacterial population dynamics, Chlorobi, Bacteroidetes-like bacteria, Filamentous-like bacteria

서일원 Il Won Seo , 박인환 In Hwan Park , 김영도 Young Do Kim , 한은진 Eun Jin Han , 추민호 Min Ho Choo , 문현생 Hyun Saing Mun

DOI: Vol.29(No.3) 383-392, 2013

In this research, mixing behavior of the floating pollutant such as oil spill accidents was analyzed by studying the advection-diffusion of GPS floaters at water surface. The LPT (Lagrangian Particle Tracking) model of EFDC (Environmental Fluid Dynamics Computer Code) was used to simulate the motion of the GPS floater tracer. In the field experiment, 35 GPS floaters were injected at the Samun Bridge of Nakdong River. GPS floaters traveled to downstream about 700 m for 90 minutes. The field data by the GPS floater experiments were compared with the simulation in order to calibrate the parameter of LPT model. The turbulent diffusion coefficient of LPT model was determined as KH / hu* = 0.17 from the scatter diagram. The arrival time of peak concentration and transverse diffusion from the simulation results were similar with the experiments from the concentration curves. Numerical experiments for anticipation of damage from floating pollutant were conducted in the same reach of the Nakdong River and the results show that the pollutant cloud transported to the left bank where the Hwawon pumping station is located. For this reason, it is suggested that the proper action should be needed to maintain the safety of the water withdrawal at the Hwawon pumping station.

Floating pollutant, GPS floater tracer test, LPT model, Mixing analysis, Turbulent diffusion coefficient

박재홍 Jae Hong Park , 박배경 Bae Kyoung Park , 이재관 Jae Kwan Lee , 류덕희 Doug Hee Rhew

DOI: Vol.29(No.3) 393-399, 2013

To control organic matters, it needs to manage not only biodegradable organic matters but also refractory organic matters. Refractory organic matters from municipal wastewater, industrial wastewater, non-point sources and etc., have been continuously discharged to the near watersheds. It is estimated that the refractory organic matter ratios are continuously increased in waterbody. In watersheds of the Total Maximum Daily Loads (TMDLs), it was investigated that COD/BOD ratios increased in many unit watersheds of the 4 major river basins. The portions COD/BOD ratios increased were found to be a 97% of Geum River unit watersheds, a 81% of Yeongsan/Seumjin River unit watersheds, a 78% of Nakdong River unit watersheds, a 70% of Han River unit watersheds, respectively. Therefore, it has become important for establishment of effective management strategies to control refractory organic matter in watersheds of the Total Maximum Daily Loads (TMDLs). In order to properly manage organic matters including refractory organic matters, the present organic indicator (BOD) has to be converted to TOC (or COD). Compared to COD and BOD, TOC, as a organic matter indicator, is evaluated more appropriate.

BOD, COD cr, COD Mn, Refractory organic matter, TOC

박재홍 Jae Hong Park , 이재관 Jae Kwan Lee , 오승영 Seung Young Oh , 류덕희 Doug Hee Rhew

DOI: Vol.29(No.3) 400-408, 2013

Total phosphorus was set as a target indicator to prevent eutrophication and algae growth, etc., in three major rivers (Nakdong River, Geum River and Yeongsang/Seomjin River) for the second phase (2011 ∼ 2015) in total maximum daily loads (TMDLs) system. However, total phosphorus management was restrictively introduced, i.e., upstream of the Lake Daechung, in the Geum River watershed. Total phosphorus concentration and trophic levels in downstream of the Lake Daechung (include Mangyeong and Dongjin rivers) were increased more than upstream. Therefore, it is necessary to expand total phosphorus management in all watersheds of the Geum River. If total phosphorus was managed in all area of the Geum River watershed, it is possible to decrease total phosphorus concentration and trophic levels, and solve the unbalanced water quality between up and downstream of the Lake Daechung.

Total phosphorus, Trophic state, Water quality target, Watershed management

황윤정 Yoo Jung Hwang , 신상희 Sang Hee Shin , 박종숙 Jong Suk Park

DOI: Vol.29(No.3) 409-419, 2013

In this study, the analytical method for 27 residual pharmaceuticals in raw water was developed. Online sample preconcentration/extraction and analysis with high resolution Orbitrap mass spectrometry (LC-ESI/Orbitrap MS) were performed. The calibration curves showed good linearities (above r2 = 0.998) in the range of 5 ∼ 1,000 ng/L. The method detection limit and the limit of quantification were 1.1 ∼ 10.0 ng/L and 3.4 ∼ 31.7 ng/L, respectively. Recoveries of the target compounds were between 70.1% and 115.8% (except cefadroxil, cefradine, vancomycin, and iopromide (50.2 ∼ 67.0%)). The optimized analytical method can be useful to determine the residual pharmaceuticals in raw water.

High resolution, Online sample pre-concentration, Orbitrap LC-ESI-MS, Residual pharmaceuticals

신이숙 Yee Sook Shin , 정선아 Sun A Chong , 신재기 Jae Ki Shin

DOI: Vol.29(No.3) 420-427, 2013

In this study, the ecological characteristics of Limnoperna fortunei were surveyed as a preceding research to solve the problem such as biofouling or biowaste caused by those organisms in the closed water pipeline. Limnoperna fortunei was collected not in the main reaches of Somjin River but inside and outside of the intake tower which is located in the lower part of Sueo Reservoir. The dense populations were found at the inlet mouth and near part of the pipeline. Their byssuses were formed as a thick and tightly interwind mat. The rusted parts of the pipeline hold relatively more shells than those of the normal parts. Average count of the numbers ranged 12.1∼136.5 ind./㎡ through the sampling stations (A,B and C). The amount of attached shells at each station were A=386, B=258, and C=71, respectively. The relationships of shell height-length and shell length-width were proportional. The majority sizes in each station ranged A=20.01∼22.00 mm (33.9%), B=10.01∼14.00 mm (51.2%), and C=18.01∼20.00 mm (22.5%), 24.01∼26.00 mm (21.1%), respectively. Most of the bigger size of shells on C station was found dead. The ecological habitat seemed less suitable for Limnoperna fortunei when they located farther away from the intake tower of reservoir. From now on, it is necessary to consider the continuous monitoring of this organism.

Biofouling, Intake tower, Limnoperna fortunei, Pipeline, Water supply

김용진 Yong Jin Kim , 이옥민 Ok Min Lee

DOI: Vol.29(No.3) 428-437, 2013

Physico-chemical water quality parameters and the phytoplankton communities from 12 sites in Oship-stream, Songchunstream, and Namdae-stream, located Gyeongsangbukdo Uljin-gun, Yeongdeok-gun, and Pyeonghae-eup respectively, were investigated from April 2009 to February 2010. Oship-stream, which is an open estuary, was easily affected by ocean current compared to that of Songchun-stream and Namdae-stream. OS3 and OS4 conductivity was higher with a season average of 3,397 μs/cm. The streams were mesotrophic to hypertrophic. Biological oxygen demand (BOD) was about 3mg/L, which was level 2 on the water quality ratings, but a concentration of 5mg/L in April 2009 indicated increased pollution due to drought. A total of 118, 117, and 124 phytoplankton taxa were found in Oship-stream, Songchun-stream, and Namdae-stream, respectively. The apparent dominant species in the polluted waters included Cryptomonas ovata, Fragilaria construens var. venter, Oscillatoria limnetica, O. limosa, and Phormidium tenue. All of Oship-stream, SC2 and SC4 of Songchun-stream, and ND3 of Namdae-stream were eutrophic as a result of standing crop analysis. BOD was highly correlated with chlorophyll-a content(r=0.52). Phosphorus concentration and proliferation of phytoplankton were thought to most affect BOD concentration in all three streams.

Chlorophyll-a, Eutrophic, Physico-chemical factors, Phytoplankton

이상진 Sang Jin Yi

DOI: Vol.29(No.3) 438-442, 2013

According to Geum-River restoration project, given conditions for management of water environment in the Geum-River were changed. Because of those changes, this study was investigated the establishment of water quality standards and water quality target in the Geum-River basin. For management of water environment in the Geum-River, the sub-basins and watersheds are newly divided and the water quality and ecosystem standards in the sub-basins are reestablished. Considering the consistency of water environment policy and legal system, the legal name of sub-basins and watersheds are unified. TMDL (total maximum daily load) should be implemented in the sub-basin where exceeds the water quality standards and the number of water pollutant among the water quality parameters which exceeds the water quality standards are extremely minimized. The water quality target of water pollutant for implementation of TMDL should be established same or higher concentration of water quality standards.

Geum-River basin, Sub-basin, TMDL, Water quality standard, Water quality target, Watershed