김종민 Jongmin Kim , 신기식 Kisik Shin , 유순주 Soonju Yu , 이정서 Jungseo Lee , 김웅기 Woongki Kim

DOI:10.15681/KSWE.2015.31.5.453 Vol.31(No.5) 453-459, 2015

This paper aims to evaluate the results of acute toxicity testing with Daphnia magna and Vibrio fischeri and characteristics of ionic substance of treated effluent which contained salt. Acute toxicity with Daphnia magna and Vibrio fischeri and salinity of 19 samples (4 business categories) were analysed. Salinity of effluent could explain the fluctuation of toxicity with D. magna about 66% ~ 91% (r2 = 0.66 ~ 0.91). The results of acute toxicity testing with V. fischeri of treated effluent (aggregate manufacture facilities) did not indicate toxicity (TU = 0), whereas that of chemical manufacture facilities indicated toxicity. V. fischeri, a candidate test organism, seemed suitable test organism for acute toxicity testing of effluent except high salinity (above 65‰ ~ 70‰) in aggregate manufacture facilities (nonmetalic minerals facilities). The performance of ion composition about treated effluent of surveyed facilities indicated that ion concentration of Na+ (5,740 mg/L) and Cl- (9,727 mg/L) showed high level among 6 major ions (Na+, K+, Ca2+, Mg2+, SO4 2-, Cl-) in effluent of nonmetalic minerals facilities. In addition, Clion seemed to influence the D. magna survival rather than Na+ ion.

acute toxicity, Daphnia magna, effluent, salt, ionic substance, Vibrio fischeri

김용진 Yongjin Kim , 윤석제 Seokjea Youn , 김헌년 Hunnyun Kim , 황문영 Moonyoung Hwang , 박진락 Jinrak Park , 이병천 Byoungcheun Lee , 이재관 Jaekwan Lee

DOI:10.15681/KSWE.2015.31.5.460 Vol.31(No.5) 460-467, 2015

We analyzed the formation of phytoplankton community and the occurences of odorus compound from benthic cyanobacteria in North, South Han-River, Paldang-Lake and Kyeongan-Stream sediments. Sediments were incubated in different water temperature. Akinetes were found (0~500 cells/g) with the highest number on sediment in Yangsoo railroad bridge (YC). The result showed that Anabaena ranged between 0.02~0.53×103 cells/mL in Sambong (SB), YC, Mukhyen-Stream (MS), Paldang-Lake (P2) and Kyeongan-Stream (KK). The total 68 taxa of phytoplankton were observed during the incubation period. A standing crop of phytoplankton was in the range of 0.13~8.97×103 cells/mL and Microcystis appeared in SB, YC, P2 and KK sites with 20~25°C temperature. In South Han-River (P3), Oscillatoria tenuis was dominant at 25°C temperature. The concentration of geosmin was the highest in SB-15°C (25.5 ng/L), and the concentration of 2-MIB was the highest in P3-25°C (286.8 ng/L). Odorous compounds were detected in all the temperature conditions from each site. Our results indicate that the dominant benthic cyanobacteria (O. tenuis, O. limosa, Phormidium tenue and Pseudanabaena limnetica) have high correlation with the occurrence odorous compounds and 2-MIB.

2-MIB, Benthic cyanobacteria, Geosmin, Phytoplankton, Sediment

정상조 Sangjo Jeong , 최형진 Hyungjin Choi , 박상진 Sangjin Park , 이준일 Juneil Lee

DOI:10.15681/KSWE.2015.31.5.468 Vol.31(No.5) 468-475, 2015

Various methods to degrade explosives efficiently in natural soil and water that include trinitrotoluene (TNT) have been studied. In this study, TNT in water was degraded by reduction with palladium (Pd) catalyst impregnated onto alumina (henceforth Pd-Al catalyst) and formic acid. The degradation of TNT was faster when the temperature of water was high, and the initial TNT concentration, pH, and ion concentration in water were low. The amounts of Pd-Al catalyst and formic acid were also important for TNT degradation in water. According to the experimental results, the degradation constant of TNT with unit mass of Pd-Al catalyst was 8.37 min-1g-1. The degradation constant of TNT was higher than the results of previous studies which used zero valent iron. 2,6-diamino-4-nitrotoluene and 2-amino-4,6-dinitrotoluene were detected as by-products of TNT degradation showing that TNT was reduced. The by-products of TNT were also completely degraded after reaction when both Pd-Al catalyst and formic acid existed. Even though there are several challenges of Pd-Al catalyst (e.g., deactivation, poisoning, leaching, etc.), the results of this study show that TNT degradation by Pd-Al catalyst and formic acid is a promising technique to remediate explosive contaminated water and soil.

Catalyst, Degradation, Formic acid, Palladium, Trinitrotoluene

김종대 Jongdae Kim , 한상무 Sangmoo Han , 정병곤 Byunggon Jeong

DOI:10.15681/KSWE.2015.31.5.476 Vol.31(No.5) 476-481, 2015

Water permeable block was manufactured using waste sewage sludge, loess and clay for the purpose of recycling waste sludge due to the prohibition of waste sludge ocean dumping. Experiments for determining optimum mixing ratio was conducted by changing sludge content in water permeable block as 5~20%. In respect of compressive strength, 1,600 N/cm2 (163.3 kg/cm2) was obtained when the mixing ratio of sludge : loess : clay were maintained by 5% : 65% : 30%, 10% : 65% : 25% and 15% : 65% : 20%, respectively. These mean that relatively high compressive strength can be obtained when the sludge content is maintained 5, 10, 15% at the 65% of loess content. In terms of water permeability and absorption rate, the higher values can be obtained as the sludge content increases. The optimum mixing ratio of sludge : loess : clay came out to be 15% : 65% : 20% when water permeability, absorption and strength were considered altogether, which matches the result observed by an electron microscope. The heavy metal leaching test result of the prepared permeable block appeared to satisfy the environmental standard in the content of Cd, Cu, Pb and As.

Clay, Loess, Waste sewage sludge, Water permeable block

한정호 Jeongho Han , 박윤식 Younshik Park , 금동혁 Donghyuk Kum , 정영훈 Younghun Jung , 정교철 Gyocheol Jung , 김기성 Kisung Kim , 임경재 Kyoungjae Lim

DOI:10.15681/KSWE.2015.31.5.482 Vol.31(No.5) 482-490, 2015

In this study, considering the factors that affects sediment trapping efficiency of Vegetative Filter Strips (VFS), the scenarios were designed to develop a regression equation to estimate sediment trapping efficiency of VFS for agricultural fields in South-Korea. For this, general conditions of agricultural fields in South-Korea were investigated. Then, based on these results, total 53,460 scenarios were set and simulated by Vegetative Filter Strip MODel (VFSMOD-w). Two variables were determined from the results of 53,460 scenarios. These two variables were applied to CurveExpert for development of a equation, which can estimate sediment trapping efficiency of VFS. The equation developed in this study can be used in SWAT model for estimation of sediment reduction efficiency of VFS to upland field in Korea. Moreover, it is expected that VFS will be effectively applied to agricultural fields in South-Korea.

Sediment, Sediment reduction, SWAT, Vegetative filter strips, VFSMOD-w

조홍래 Honglae Cho , 정의상 Euisang Jeong , 구본경 Bhonkyoung Koo

DOI:10.15681/KSWE.2015.31.5.491 Vol.31(No.5) 491-506, 2015

Distributed models represent watersheds using a network of numerous, uniform calculation units to provide spatially detailed and consistent evaluations across the watershed. However, these models have a disadvantage in general requiring a high computing cost. Semi-distributed models, on the other hand, delineate watersheds using a simplified network of non-uniform calculation units requiring a much lower computing cost than distributed models. Employing a simplified network of non-uniform units, however, semi-distributed models cannot but have limitations in spatially-consistent simulations of hydrogeochemical processes and are often not favoured for such a task as identifying critical source areas within a watershed. Aiming to overcome these shortcomings of both groups of models, a hybrid watershed model STREAM (Spatio-Temporal River-basin Ecohydrology Analysis Model) was developed in this study. Like a distributed model, STREAM divides a watershed into square grid cells of a same size each of which may have a different set of hydrogeochemical parameters reflecting the spatial heterogeneity. Like many semi-distributed models, STREAM groups individual cells of similar hydrogeochemical properties into representative cells for which real computations of the model are carried out. With this hybrid structure, STREAM requires a relatively small computational cost although it still keeps the critical advantage of distributed models.

Hybrid Watershed Model, Hydrology, Nonpoint source pollution, Sediment, Water quality

조홍래 Honglae Cho , 정의상 Euisang Jeong , 구본경 Bhonkyoung Koo

DOI:10.15681/KSWE.2015.31.5.507 Vol.31(No.5) 507-522, 2015

In this study, some of the model verification results of STREAM (Spatio-Temporal River-basin Ecohydrology Analysis Model), a newly-developed hybrid watershed model, are presented for the runoff processes of nonpoint source pollution. For verification study of STREAM, the model was applied to a test watershed and a sensitivity analysis was also carried out for selected parameters. STREAM was applied to the Mankyung River Watershed to review the applicability of the model in the course of model calibration and validation against the stream flow discharge, suspended sediment discharge and some water quality items (TOC, TN, TP) measured at the watershed outlet. The model setup, simulation and data I/O modules worked as designed and both of the calibration and validation results showed good agreement between the simulated and the measured data sets: NSE over 0.7 and R2 greater than 0.8. The simulation results also include the spatial distribution of runoff processes and watershed mass balance at the watershed scale. Additionally, the irrigation process of the model was examined in detail at reservoirs and paddy fields.

Calibration, Hybrid watershed model, Nonpoint source pollution, Sensitivity analysis, Validation, Verification

이준호 Junho Lee , 양승호 Seungho Yang , 방기웅 Kiwoong Bang

DOI:10.15681/KSWE.2015.31.5.523 Vol.31(No.5) 523-532, 2015

Hydrocyclone is widely used in industry, for its simple design, high capacity, low maintenance and low operational cost. The objective of this study is to develop hydrocyclone coagulation and filtration system. The system is made of hydrocyclone ballasted coagulation with polyaluminium chloride silicate (PACS) and upflow filter to treat micro particles in urban storm runoff. Roadside sediment particles (<200 μm) was mixed with tap water to make various turbid suspensions to simulate urban storm runoff. The filter cartridge was filled with polyethylene media system and ran 1hr per everyday and total operation time were 8.19hrs and backwashing everyday after end of operation. The operation condition of flowrate was 8.2~11.9 m3/day (mean 10.1 m3/day) and surface overflow rate (SOR) based on filter surface area was 45.5~65.9 m3/m2/day (mean 55.7 m3/m2/day). The range of PACS dosage concentration was 14.0~31.5 mg/L. As the results of operation, the range of removal efficiency of turbidity, SS were 81.0~95.8% (mean 89.5%) 81.8~99.0% (mean 91.4%), respectively. An increase of filtration basin retention time brought on increased of removal efficiency of turbidity and SS, and increase of SOR brought on decreased of removal efficiency. During the first flush in urban area, storm runoff have an high concentration of SS (200~600 mg/L) and the filtration bed becomes clogged and decreased of removal efficiency. Backwashing begins when the drainage pipe valve at the filtration tank bottom is completely open (backwashing stage 1). Backwashing stage 2 was using air bubbles and water jet washing the media for 5 mins and open the drainage valve. After backwashing stage 1, 2, 61.83~64.04%, 18.53~27.51% of SS loading was discharged from filtration tank, respectively. Discharged SS loading from effluent was 7.12~14.79% and the range of residual SS loading in fliter was 2.26~5.00%. The backwashing effects for turbidity, SS were 89.5%, 91.4%, respectively. The hydrocyclone coagulation and filtration with backwashing system, which came out to solve the problems of the costly exchange filter media, and low efficiency of removing micro particles of filter type nonpoint treatment devices, is considered as an alternative system.

Backwash, Coagulation, Hydrocyclone, Storm runoff, Upflow filtration

오경희 Kyounghee Oh , 김용준 Yongjun Kim , 조영철 Youngcheol Cho

DOI:10.15681/KSWE.2015.31.5.533 Vol.31(No.5) 533-542, 2015

In order to investigate the effect of internal loading from sediment on algal blooming at Chusori area in Daechung Reservoir, the amount and contamination level of sediment and the release rate of total phosphorus were analyzed. The sedimentary layer was consisted with two layers, and the average depth of upper and lower ones were 0.35 and 1.44 m, respectively. The fraction of inorganic phosphorus in the sediment was higher than that of organic phosphorus, and the fractions of phosphorus which responsible for internal loading were very high as in the range of 72.7 and 80.2% of inorganic phosphorus. The C/N ratio of sediment taken with core sampler indicated the organic compounds are originated from settled algae from water body. The average release rate of total phosphorus from sediment was 6.74 (±0.50) mg/m2/day. These results indicated that the internal loading from sediment contributes the excessive algal growth at Churosi area, and the countermeasures to improve the quality of sediments are required to manage algal blooming in Daechung Reservoir.

Chusori, Daechung reservoir, Internal loading, Nutrient release rate, Sediment

정영훈 Younghun Jung , 금동혁 Donghyuk Kum , 한정호 Jeongho Han , 장춘화 Chunhwa Jang , 양재의 Jaye Yang , 임경재 Kyoungjae Lim , 김기성 Kisung Kim

DOI:10.15681/KSWE.2015.31.5.543 Vol.31(No.5) 543-555, 2015

The existing standard for soil erosion risk assessment has limitations in sustainable topsoil management since the fixed criteria are applied to determination of soil erosion risk areas regardless of land use types. It may not be necessary to apply soil erosion best management practices to agricultural areas with high potential of soil erosion because human or economic damage derived from soil erosion might be tiny in that region. Furthermore, the fixed criterion with absolute values can select too many hot spots of soil erosion to conduct efficient soil erosion management. Thus, objective of this study was to suggest the relative criteria using statistical analysis for efficient soil erosion management. In future, the relative indices for soil erosion prevention should be improved to provide a priority of soil erosion management considering economic damage from soil erosion or functional values of soil with quantitative soil erosion. Additional researches will be needed to reflect a regional characteristics and to consider various land use types and different criteria.

Absolute criteria, Relative criteria, Soil erosion, Topsoil, Topsoil erosion indices, Topsoil management

김지연 Jiyeon Kim , 김병군 Byunggoon Kim , 김홍석 Hongsuck Kim , 윤주환 Zuwhan Yun

DOI:10.15681/KSWE.2015.31.5.556 Vol.31(No.5) 556-562, 2015

In order to remove the organic substances and the nitrate-nitrogen contained in wastewater, some researchers have studied the simultaneous removal of organics and nitrogen by using different biocathode microbial fuel cells (MFCs). The operating conditions for removing the contaminants in the MFCs are the external resistances, HRTs, the concentration of the influent wastewater, and other factors. This study aimed to determine the effect of the external resistors and organic loading rates, from the changing HRT, on the removal of the organics and nitrogen and on the production of electric power using the Denitrification Biocathode - Microbial Fuel Cell (DNB-MFC). As regards the results of the study, the removal efficiencies of SCODCr did not show any difference, but the nitrate-nitrogen removal efficiencies were increased by decreasing the external resistance. The maximum denitrification rate achieved was 129.2 ± 13.54 g NO3 --N/m3/d in the external resistance 1 Ω, and the maximum power density was 3,279 mW/m3 in 10 Ω. When the DNB-MFC was operated with increasing influent organic and nitrate loading by reducing the HRTs, the NO3 --N removal efficiencies were increased linearly, and the maximum nitrate removal rate was 1,586 g NO3 --N/m3/d at HRT 0.6 h.

Biocathode microbial fuel cell, Denitrification, External resistance, Influent loading rate, Simultaneous organic and nitrate removal

김현구 Hyungu Kim , 엄한기 Hanki Eom , 이동호 Dongho Lee , 주현종 Hyunjong Joo

DOI:10.15681/KSWE.2015.31.5.563 Vol.31(No.5) 563-568, 2015

Natural Organic Matter (NOM) is a precursor of disinfection by products. Recently, with the increase in NOM concentration caused by a large amount of algae, the creation of disinfection by-products is becoming a big issue. Therefore, in this study, PAC+Membrane+F/A hybrid process was organized to control disinfection by-products in small-scale water treatment plants. The optimal dosage of PAC was set at 20 mg/L through Lab. scale test. Also, it is judged that NOM concentration must be less than 1.0 mg/L to meet the recommended criteria of drinking water quality monitoring items of disinfection by-products during chlorination. The existing conventional water treatment process was compared to the independent F/A process and the PAC +Membrane+F/A hybrid process through pilot plant operation, and the result showed that there is a need to apply an advanced water treatment process to remove not only NOMs but also Geosmin caused by algae. Accordingly, it is considered that applying the PAC+Membrane+F/A process will help in controling a clogged filter caused by a large amount of algae and disinfection by-products created by chlorination and can be used as an advanced water treatment process to meet the recommended criteria of drinking water quality monitoring items.

F/A, Membrane, NOM, Powdered Activated Carbon, TOC

황하선 Hasun Hwang , 박지형 Jihyung Park , 김용석 Yongseok Kim , 류덕희 Doughee Rhew , 최유진 Yujin Choi , 이성준 Sungjun Lee

DOI:10.15681/KSWE.2015.31.5.569 Vol.31(No.5) 569-575, 2015

The current Total Pollution Load Control (TPLC) sets the Target Water Quality (TWQ) by utilizing the delivery ratio, unit loads, and water quality modeling, it also allocates the watershed’s permitted discharge load. Currently, common target pollutants of every unit watershed in TPLC are BOD and T-P. This study has reviewed the 1th and 2th of TWQ setting process for the Nakdong River 3th TWQ setting in Total Pollution Load Control (TPLC). As a result of review, 1th and 2th were divided into one management basin (mulgeum) for setting management goals. However, 3th was divided into six management basins (mulgeum, gnagjeong, geumho river, nam river, miryang river, end of nakdong river). The principle of management goal setting were to achieve the objective criteria of Medium Areas for the linkage of the water environment management policy. And Anti-Degredation (principle of preventing deterioration) were applied to the 3th TWQ. Also, additional indicators were considered in accordance with the reduction scenarios for the final management goals.

Management Basin, Management Goal, Nakdong River Basin, Total Pollution Load Control, TPLC, Target Water Quality, TWQ

안기홍 Kihong Ahn , 유홍덕 Hongdeok Ryu , 김용석 Yongseok Kim

DOI:10.15681/KSWE.2015.31.5.576 Vol.31(No.5) 576-582, 2015

In recently, the Korea government is concerning on non-point source pollution management to improve water quality. The objective of this paper is to investigate the improvement measurement for management of livestock wastes. As a result, we find that the National Pollution Source Survey is necessary to establish the unified database system with the Korea Statistics(KOSAT) in order to minimize the difference between relevant data. The investigation for environmental impact of livestock manure should be supported the designation of control areas and establishment of the technical guidelines including target material, monitoring site, standard method, etc. In addition, it should be followed by appropriate nutrient recycling and proper fertilizer usage based on social consultation and cost-benefit analysis.

Environmental Impact Investigation, Livestock manure, National Pollution Source Survey, Systems Improvement, Water quality management