유익근 Ik Keun Yoo

DOI:10.15681/KSWE.2014.30.1.001 Vol.30(No.1) 1-7, 2014

The purpose of this study was to investigate the nitrification characteristics of biological aerated filter (BAF) packed with Ceramic media, especially focusing on nitrite build-up during nitrification. When increasing the nitrogen load above 1.63 kgNH4(+)-N/m3d, ammonium removal efficiency decreased to less than 60% and the nitrite ratio (NO2+-N/NOx-N) of higher than 75% was achieved due to the inhibitory free ammonia (FA, NH3-N) concentration and oxygen limitation. FA inhibition, however, is not recommended strategy to promote nitrite build-up since FA concentration in the reactor is coupled with decreased ammonium removal efficiency. Nitrite ratio in the effluent was also affected by aeration rate and influent ammonium concentration. Ammonium oxidation was enhanced at a higher aeration rate regardless of influent ammonium concentration but, the nitrite ratio was dependent on both aeration rate and influent ammonium concentration. While a higher nitrite ratio was obtained when BAFs were fed with 50 mgNH4(+)-N/L of influent, the nitrite ratio significantly decreased for a greater influent concentration of 200-300 mgNH4(+)-N/L. Taken together, aeration rate, influent ammonium concentration and FA concentrations kept in the BAF were found to be critical variables for nitrite accumulation in the BAF system.

Biological Aerated Filter, Nitrification, Nitrite, Wastewater

권헌각 Heon Gak Kwon , 이재운 Jae Woon Lee , 이윤정 Youn Jeong Yi , 천세억 Se Uk Cheon

DOI:10.15681/KSWE.2014.30.1.008 Vol.30(No.1) 8-15, 2014

In this study, regression equation was analyzed to estimate non-point sources (NPS) pollutant loads in orchard area. Many Factors affecting the runoff of NPS pollutant as precipitation, storm duration time, antecedent dry weather period, total runoff density, average storm intensity and average runoff intensity were used as independent variables, NPS pollutant was used as a dependent variable to estimate multiple regression equation. Based on the real measurement data from 2008 to 2012, we performed correlation analysis among the environmental variables related to the rainfall NPS pollutant runoff. Significance test was confirmed that T-P (R2=0.89) and BOD (R2=0.79) showed the highest similarity with the estimated regression equations according to the NPS pollutant followed by SS and T-N with good similarity (R2>0.5). In the case of regression equation to estimate the NPS pollutant loads, regression equations of multiplied independent variables by exponential function and the logarithmic function model represented optimum with the experimented value.

load, nonpoint source, statistic tool, storm runoff

나은혜 Eun Hye Na , 신창민 Chang Min Shin , 박란주 Lan Joo Park , 김덕길 Duck Gil Kim , 김경현 Kyung Hyun Kim

DOI:10.15681/KSWE.2014.30.1.016 Vol.30(No.1) 16-24, 2014

A combined watershed and receiving waterbody model was developed for operational water flow forecasting of the Nakdong river. The Hydrological Simulation Program Fortran (HSPF) was used for simulating the flow rates at major tributaries. To simulate the flow dynamics in the main stream, a three-dimensional hydrodynamic model, EFDC was used with the inputs derived from the HSPF simulation. The combined models were calibrated and verified using the data measured under different hydrometecological and hydraulic conditions. The model results were generally in good agreement with the field measurements in both calibration and verification. The 7-days forecasting performance of water flows in the Nakdong river was satisfying compared with model calibration results. The forecasting results suggested that the water flow forecasting errors were structures such as upstream dams and weirs. From the results, it is concluded that the combined watershed-waterbody model could successfully simulate the water flows in the Nakdong river. Also, it is suggested that integrating real-time data and information of dam/weir operation plans into model simulation would be essential to improve forecasting reliability.

EFDC model, HSPF model, Nakdong River, Water flow forecasting

김성옥 Sung Ok Kim , 김학성 Hag Seong Kim

DOI:10.15681/KSWE.2014.30.1.025 Vol.30(No.1) 25-30, 2014

This study is done to prove the premise that both alkalinity and hardness affect on the dissolved phosphorus concentration so that the growth of algae is also affected in water bodies like rivers and lakes. Statistical analysis of the water quality data of 13 reservoirs collected for the last decade shows the relations between alkalinity and chlorophyll-α and between haedness and chlorophyll-α are not linear but follow second order equation. This relation seems to be due to two antagonistic effects accompanying a simultaneous increase in alkalinity and hardness. The increase stimulates the growth of algae by supplying carbonates and Ca2(+) to algae and at same time it causes a decrease in soluble phosphorus which retards algae to grow. These opposing tendencies are confirmed by theoretical calculations with the MNTEQ model. There seems to be ranges of alkalinity and hardness that are in favor of algae growth; the ranges are less than 44mg/L as CaCO3 in alkalinity and also less than 63mg/L as CaCO3 in hardness. This finding will provide a solid base to develop an effective water quality management of water bodies.

Algae, Alkalinity, Chlorophyll-α, Hardness, MINTEQ model, Soluble phosphorus

박형석 Hyeung Seok Park , 정세웅 Se Woong Chung

DOI:10.15681/KSWE.2014.30.1.031 Vol.30(No.1) 31-43, 2014

Recently, Andong Reservoir and Imha Reservoir located in Nakdong River basin (Korea) are being connected by a tunnel (length 2km, diameter 5.5m) for a conjunctive use. The objectives of this study were to construct a two dimensional(2D) laterally-averaged model for two reservoirs, and examine the effects of connection on the water transportation and temperature stratification in the reservoirs. The 2D models for each reservoir were calibrated using field data obtained in 2006, and applied to the linked system for the year of 2002 when a severe flood intruded into Imha Reservoir during the typhoon Rusa. Simulation results showed that 364 million m3 of water can be conveyed from Imha to Andong, while 291 million m3 of water from Andong to Imha after connection. It resulted in 1.38 m increase of annual averaged water level in Andong Reservoir, whereas 3.75 m decrease in Imha Reservoir. The structures of thermal stratification in both reservoirs were influenced in line with the flow exchanges. In Andong Reservoir, the location of thermocline moved upward about 10 m compared to an independent operation. The results imply that the persistent turbidity issue of Imha Reservoir might be shifted to Andong Reservoir during a severe flood event after connection.

Andong-Imha connection, CE-QUAL-W2, Reservoirs connection, Temperature stratification, Water Transportation

김경훈 Gyeong Hoon Kim , 정강영 Kang Young Jung , 이인정 In Jung Lee , 이경락 Kyung Lak Lee , 천세억 Se Uk Cheon , 임태효 Tae Hyo Im , 윤종수 Jong Su Yoon

DOI:10.15681/KSWE.2014.30.1.044 Vol.30(No.1) 44-59, 2014

Despite the implementation of TMDL, the water quality in lower watershed of Nam river dam has worsened continuously since 2005. Multifarious pollution sources such as cities and industrial districts are scattered around it. Nam river downstream bed slope is very gentle towards the downstream water flow of slows it down even more, depending on the water quality deterioration is accelerated eutrophication occurs. In this study, the mainstream in lower watershed of Nam river dam region to target aquatic organic matter by phytoplankton growth contribution was evaluated by statistical analysis. And statistical evaluation of water quality and the accuracy of forecasting, model calibration and verification procedures by completing QUALKO2 it`s eutrophic phenomena that occur frequently in the dam outflow through scenarios predict an increase in water quality management plans to present the best should.

Dam out flow, Nam river watershed, Multivariate analysis, Pearson correlation coefficient, QUAL2E, QUALKO2

김경훈 Gyeong Hoon Kim , 정강영 Kang Young Jung , 윤종수 Jong Su Yoon , 천세억 Se Uk Cheon

DOI:10.15681/KSWE.2014.30.1.060 Vol.30(No.1) 60-67, 2014

In this study, four methods for calculation of continuous daily flow was suggested using short-term or partial recording station of stream flow including missing data. Using these methods, standard flows at the outlet of unit/small basins for the management of total maximum daily loads (TMDLs) in Nam gang dam basin were estimated from full-period flow duration curve (FDC). Four methods of extension are described, and their properties are explored. The methods are regression (REG), regression plus noise (RPN), and maintenance of variance extension types 1 and 2 (MOVE.1, MOVE.2). In these methods, the continuous daily flow was calculated using extension equation based on correlation analysis, after conducting the correlation analysis between historic record of stream flow and long-term recording station (a base station). Finally the best optimal method was selected as the MOVE.2, and the standard flows in the abundant, ordinary, low and drought flow estimated from FDC was evaluated using MOVE.2 in unit/small basins.

MOVE.1, MOVE.2, REG, RPN, Streamflow record extension technique, TMDLs

최아름 Ah Reum Choi , 김아름 Ah Reum Kim , 손세환 Se Hwan Son , 양희정 Hee Jung Yang , 공동수 Dongsoo Kong

DOI:10.15681/KSWE.2014.30.1.068 Vol.30(No.1) 68-79, 2014

There are marked differences in climate condition between east-facing slopes and west-facing slopes in Mt. Seorak (1,708 m). This study was conducted to find out the differences of benthic macroinvertebrate communities between both slopes of Mt. Seorak. Quantitative (Surber net; 30 cm х 30 cm, mesh: 1 mm) and qualitative (Hand net; mesh: 1 mm) samplings ware carried out seasonally in each site which had 100-meter-high difference from November 2010 to November 2011. Most of the survey sites showed sound environmental conditions because they were located in the protection area of the national park. The benthic macroinvertebrates collected from all survey sites were composed of 158 species, 62families, 17 orders, 7 classes and 5phyla. DCA (Detrended Correspondence Analysis) ordination based on the abundance of benthic mactoinvertebrates showed that altitude was a major factor governing the structure of benthic macroinvertebrate community. There was no significant difference of the communities between both slopes.

Altitude, Benthic macroinvertebrates, DCA Ordination, Mt, Seorak, Slope

유지수 Jisu Yoo , 이보미 Bo Mi Lee , 허진 Jin Hur , 정진호 Jinho Jung

DOI:10.15681/KSWE.2014.30.1.080 Vol.30(No.1) 80-86, 2014

Unlike to natural organic matters (NOMs), effluent organic matters (EfOMs) are not well understood due to their complexity and heterogeneity. In this study, EfOMs from sewage and industrial wastewater treatment effluents and Suwannee River NOM (SRNOM) were isolated into hydrophobic (HPO), transphobic (TPI) and hydrophilic (HPI) fractions. Specific ultraviolet absorbance (SUVA) and fluorescence excitation emission matrix (FEEM) analyses were used to characterize physicochemical properties. In addition, acute toxicity and oxidative stress to Daphnia magna were evaluated to characterize toxicological properties. EfOMs showed similar properties to microbially derived organic matters having low hydrophobicity, which are totally different from SRNOM having high hydrophobicity. Moreover, acute toxicity and antioxidant enzyme activity in D. magna was largely dependent on fraction types of EfOMs. These findings suggest that EfOMs have different physicochemical and toxicological properties compared with those of NOMs, which needs to be further identified with various sources of EfOMs.

Acute toxicity, Daphnia Magna, dissolved organic matter, FEEM, wastewater

최대규 Dae Gyu Choi , 박무종 Moo Jong Park , 박배경 Bae Kyung Park , 김상단 Sang Dan Kim

DOI:10.15681/KSWE.2014.30.1.087 Vol.30(No.1) 87-94, 2014

According to the technical guideline of water pollutant load management, the rainfall captured ratio which can be estimated by the empirical formula is an important element to estimate reduction loads of nin-point pollutants water quality control basin. In this study, the rainfall captured ratio is altered to stormwater captured ratio considering its meaning in the technical guideline of water pollutant load namagement, and the new empirical formula of stomwater captured ratio is suggested. In order to do this, we calculate stormwater captured ratio by using the hourly rainfall data of seven urban weather stations (Busan, Daegu, Daejeon, Gangreung, Seoul, Gwangju, and Jeju) for 43 years. The regression coefficients of the existed empirical formula cannot reflect the catchment properties at all, because they are fixed values regardless of regions. However the empirical formula of storm water captured ratio has flexible regression coefficients by runoff coefficient(c), so it is allowed to consider the characteristics of runoff in catchment. It is expected that reduction loads of storage based water quality control basin can be more reasonably estimated than before.

Non-point pollutant source, Stormwater captured curve, TMDL, Water quality control basin

김종오 Jong O Kim , 이우범 Woo Bum Lee , 박수호 Soo Ho Park

DOI:10.15681/KSWE.2014.30.1.095 Vol.30(No.1) 95-101, 2014

Overall studies for the N-nitrosodimethylamine (NDMA) formation and treatment methods were conducted. In this study, occurrence in several countries and emerging treatment rechnologies of NDMA were generally reviewed. The NDMA formation was dependent on pH, contact time, and molar ratio (monochloramine/dimethylamine). The formation was rapidly increased when the molar ratio was greater than I. It was likely that monochloramine could be related to stimulate NDMA formation. NDMA concentrations in water supply and wastewater plants after disinfection were approximately 10ng/L and 100ng/L, respectively. UV oxidation and adsorption processes are regarded as effective technologies for the NDMA removal. It is suggested that the UV oxidation with proper lamps is applied in water supply system.

Disinfection, Dimethylamine, DMA, Monochloraminc, N-nitrosodimethylamine, NDMA, Treatment method, Water supply and wasterwater