벤추라제이알 Jey R Sabado Ventura , 남지현 Ji Hyun Nam , 양빈친 Benqin Yang , 나리 Ri Na , 길혜진 Hyejin Kil , 남덕현 Deok Hyeon Nam , 강기훈 Ki Hoon Kang , 장덕진 Deokjin Jahng

DOI:10.15681/KSWE.2015.31.6.599 Vol.31(No.6) 599-609, 2015

In order to investigate why OSA (oxic-settling-anaerobic) process produces less sludge than CAS (conventional activated sludge) process, sequential cultivation through 1st aerobic-anaerobic-2nd aerobic conditions, were carried out. Then, the intracellular concentrations of adenosine triphosphate (ATP), nicotinamide adenine dinucleotide (NAD and NADH), and nicotinamide adenine dinucleotide phosphate (NADP and NADPH) were monitored for these three stages. Results showed that the concentrations of these energy substances rapidly decreased through time in both aerobic and anaerobic conditions but the anaerobic culture contained the lower energy level than aerobic culture. The 2nd aerobic culture that experienced anaerobic condition showed lower concentration of these energy substances than those of the 1st aerobic culture. Meanwhile, the anaerobic culture corresponding to the sludge holding stage of OSA was subjected to different soluble chemical oxygen demand (SCOD) levels, detention time, and temperature to evaluate the effects of these variations on the energy level difference between the 1st and 2nd aerobic stages. The lower the SCOD concentration, the longer detention time; and the higher temperature in the anaerobic stage tended to further reduce the intracellular level of the 2nd aerobic culture. On the average, the intracellular energy level of the anaerobic and 2nd aerobic stage were 57.73% and 39.12% of the 1st aerobic culture, respectively. These indicated that the insertion of an anaerobic stage between two aerobic stages could lower the intracellular energy levels, hence the lower the sludge in OSA than CAS process. Moreover, manipulation of the operating conditions of the intervening anaerobic stage can change intracellular energy levels thereby controlling sludge production.

ATP, Excess sludge, NAD(P)H, OSA, Wastewater treatment

공동수 Dongsoo Kong , 김아름 Ah Reum Kim

DOI:10.15681/KSWE.2015.31.6.610 Vol.31(No.6) 610-618, 2015

This study was conducted to find out the influence of sample size (accumulated survey areas) on the seven biological indices of benthic macroinvertebrates. BMI, the index similar to Zeilika-Marvan’s saprobic index, tended to be independent on the variations of sample size. The other indices (Shannon-Weaver’s diversity, Margalef’s richness, Menhinick’s richness, Pielou’s evenness, and Lenat’s EPT index) showed the considerable variations along with the increase of sample size and environmental conditions. To get the appropriate index values, it should be sampled at least 6 replicates more based on 30×30cm Surber sampler. In addition, the habitat heterogeneity index of benthic macroinvertebrates suggested in this study, it will be able to be used for evaluating the heterogeneity of habitats.

Benthic macroinvertebrates, Biological index, Habitat heterogeneity, Sample size, Survey area

신소연 So Yeun Shin , 김종호 Jong Ho Kim , 안종화 Johng Hwa Ahn

DOI:10.15681/KSWE.2015.31.6.619 Vol.31(No.6) 619-624, 2015

This study experimentally determined the effect of titanium tetrachloride (TiCl4) concentration ([TiCl4]) (0.25-0.55 mM) and initial pH (3-11) on phosphorus (P) removal in synthetic wastewater (2 mg P/L). The P removal efficiency increased when [TiCl4] increased. The P removal efficiency showed a parabolic trend with an inflection point at pH 7. At the molar ratio of TiCl4 and P>6.2, the P removal efficiency was over 90% and the residual P concentration was less than 0.2 mg/L. Within the design boundaries, the complete P removal could be achieved at 7.0≤initial pH≤8.5 and 0.43≤[TiCl4]≤0.55 mM. The final pH was over 5.8 at initial pH≥7.7 and [TiCl4]≥0.35 mM. The results showed that TiCl4 was effective in P removal in water so that it could be an alternative chemical for P removal.

Coagulant, Initial pH, Optimization, Phosphorus, Titanium tetrachloride

최희정 Hee Jeong Choi

DOI:10.15681/KSWE.2015.31.6.625 Vol.31(No.6) 625-631, 2015

In this study, low cost bio-flocculants, chitosan, cationic starch and Mg-sericite, were used as a flocculant to harvest freshwater microalgae, Chlorella vulgaris. Chitosan, cationic starch and Mg-sericite separated successfully >98% of C. vulgaris at following optimal parameters: 90 mg/L chitosan at pH 6-7, 70 mg/L cationic starch at pH 9-10 and 50 mg/L Mg-sericite at pH 4-5. A relatively high correlation coefficient (R2) of 0.9993 for chitosan, 0.9971 for catonic starch and 0.9924 for Mg-sericite was obtained. The investigated flocculants amount increased linearly with increasing the microalgae amount. The biopolymer, Mg-sericite, was more effective than that of other investigated flocculants. These results indicated that a bio-flocculants, chitosan, cationic starch and Mg-sericite, could prove to be an effective flocculant for economical production of microalgae biomass. In addition, Mg-sericite was more effective comparing to the other investigated flocculants.

Cationic starch, Chitosan, Flocculation, Harvesting, Microalgae, Mg-sericite

이동호 Dong Ho Lee , 김성수 Sung Su Kim

DOI:10.15681/KSWE.2015.31.6.632 Vol.31(No.6) 632-636, 2015

This study aims to evaluate arsenic adsorption efficiencies over various metal oxides (CeO2, TiO2, Fe3O4, ZrO2, AlOOH, SiO2, α-Al2O3, and γ-Al2O3) and investigate the correlation between physico-chemical characteristics of metal oxides and their efficiencies. From XPS, XRD BET analysis and isotherm adsorption test, TiO2 powder showed that the best adsorption efficiency, and it``s mechanism was highly depended on the chemical adsorption.

Adsorption, Arsenic, Magnetite, Metallic oxide, Titania

마심초 Xin Chao Ma , 임봉수 Bong Su Lim , 허순욱 Soon Uk Heo , 곽미애 Mi Ae Kwak

DOI:10.15681/KSWE.2015.31.6.637 Vol.31(No.6) 637-643, 2015

This study has been carried out to provide the basic data obtained from the evaluation of the variation of water quality around the Chudong intake tower in Daechung resevoir, which may be able to help the establishment of a pure water supply policy. Five sites around the Chudong intake tower were selected, and the average data for recent ten years(from year 2004 to year 2013) were analysed. The average water quality around Chudong intake tower are as followed; pH 7.5, DO 8.7 mg/L, BOD 1.0 mg/L, COD 3.0 mg/L, SS 3.0 mg/L, TN 1.495 mg/L, TP 0.017 mg/L, and Chlorophyll-a 6.5 mg/m3 were matched the good class by comparing with the living environment standard of reservoir. COD values of higher than 3.0 mg/L after July were likely due to non-point pollutants and algae outbreak during rainy summer season. Total phosphorus rose sharply in the summer season, and then algae watch was issued consistently for average 40 days. Total nitrogen to total phosphorus ratio was average 90, and it is important to control the inflow phosphrous from small stream for proper management to block an algae growth according to eutrophication. It was recommended to operate the algae removing boats around intake tower from July to October, and was required advanced water treatment processes to remove NBD COD and bad odor and taste due to algae growth.

Algae watch, Chudong intake tower, Management to block algae growth, Total nitrogen to total phosphorus ratio

이규열 Kyu Yeol Lee , 이권철 Kwon Choel Lee , 김주언 Ju Eon Kim , 김신 Shin Kim , 안정민 Jung Min Ahn , 임태호 Tae Hyo Im

DOI:10.15681/KSWE.2015.31.6.644 Vol.31(No.6) 644-652, 2015

In this study the releasing of nutrients from sediments of Nak-dong River were investigated. We perfomed lab-scale simulation experiments using field sediment and ware. Nutrients, orgarni matter, particle size of the sediments and nutrients of released water were analyzed. Analyzed results of the sediments, mainly composed of mS(muddy Sand) sedimentary facies and IL were 2.46~6.83%, T-N were 1.189~2.492 mg/kg, and T-P were 333~726 mg/kg in the study area. Analyzed results of the nutrients of released water, pH and TOC were each 7.8~9.2% and 31.7~40.8% decreased after 20 days. T-N increased steadily, and NH3-N increased steadily then decreased, at this time NO3-N increase. Also NH3-N increased steadily, then decreased at this time. Furthermore release of phosphorus were mostly decreased.

Nak-dong River, Nutrient, Phosphorus, Sediment, Release, Water quality

황하선 Ha Sun Hwang , 이한필 Han Pil Rhee , 박지형 Jihyung Park , 김용석 Yong Seok Kim , 이성준 Sung Jun Lee , 안기홍 Ki Hong Ahn

DOI:10.15681/KSWE.2015.31.6.653 Vol.31(No.6) 653-664, 2015

TPLMS (Total water pollutant load management system) that is the most powerful water-quality protection program have been implemented since 2004. In the implementation of TPLMS, target water-quality and permissible discharged load from each unit watershed can be decided by water-quality modeling. And NPS (Non-point sources) discharge coefficients associated with certain (standard) flow are used on estimation of input data for model. National Institute of Environmental Research (NIER) recommend NPS discharge coefficients as 0.15 (Q275) and 0.50 (Q185) in common for whole watershed in Korea. But, uniform coefficient is difficult to reflect various NPS characteristics of individual watershed. Monthly NPS discharge coefficients were predicted and estimated using surface flow and water-quality from HSPF watershed model in this study. Those coefficients were plotted in flow duration curve of study area (Palger stream and Geumho C watershed) with monthly average flow. Linear regression analysis was performed about NPS discharge coefficients of BOD, T-N and T-P associated with flow, and R2 of regression were distributed in 0.893~0.930 (Palger stream) and 0.939~0.959 (Geumho C). NPS Discharge coefficient through regression can be estimated flexibly according to flow, and be considered characteristics of watershed with watershed model.

Discharge coefficient, HSPF, Korean TMDL, TPLMS, Watershed model

김신조 Shin Jo Kim , 송효정 Hyo Jeong Song , 박태진 Tae Jin Park , 황문영 Moon Young Hwang , 조항수 Hang Soo Cho , 송광덕 Kwang Duck Song , 이형진 Hyung Jin Lee , 김영석 Young Suk Kim

DOI:10.15681/KSWE.2015.31.6.665 Vol.31(No.6) 665-679, 2015

Yearly mean temperature in the 29 lakes surveyed ranges from 12.6 (Suncheon) to 13.9°C (Mokpo), the lowest in -2.7°C (January) and the highest in 25.9°C (July). Monthly mean the amount of rainfall recorded the highest of 336.7 mm in August and the lowest with 4.9 mm in January. A total of 424 species of phytoplankton were identified. They were 157 Chlorophyceae, 161 Bacillariophyceae, 39 Cyanophyceae, and 67 other algal taxa. The phytoplankton diversity were low in stream type reservoirs such as Guemho, Youngsan and Youngam. The population density of phytoplankton ranged from 19 to 53,161 cells/ml. Annual mean of total zooplankton abundance in 45 sites was 369±827 ind./L (n=180). Rotifers were the most common taxa and their relative abundance was high (65~77%). The benthic microinvertebrate fauna of 10 reservoirs of Jeonnam province were 71 species of 61 genera of 44 families of 16 orders of 7 classes of 4 phyla. Aquatic insects of Phylum Arthropoda were 50 species of 44 genera of 28 families of 6 orders. The number of individuals was 6,132. Diptera was highiest (41.3%), and Ephemeroptera (31.0%), Trichoptera (17.5%), Anellida (3.8%), Mollusca (3.3%), Crustacea (0.4%). Large hydrophytes were identified 32 taxa, 2 varieties 30 species 26 genera and 20 families. Especially, Jijung and Juam lakes require management such as physical remove of this ecosystem disturbance field plants. Fishes were identified total 44 taxa, such as 25 Cyprinidae (56.8%), 8 Cobitidae (17.0%), 3 Gobiidae (6.4%), 2 Bagridae (4.3%), 2 Osmeridae (4.3%), 2 Odontobutidae (4.3%), 2 Centrachidae (4.3%), 1 Siluridae (2.1%), and 1 Centropomidae (2.1%). A pale chub was dominant species (18.9%).

Aquatic invertebrate, Fish, Gwangju, Large hydrophyte, Phytoplankton, Zooplankton

안지홍 Ji Hong An , 임치홍 Chi Hong Lim , 임윤경 Yun Kyung Lim , 남경배 Kyeong Bae Nam , 피정훈 Jung Hun Pi , 문정숙 Jeong Sook Moon , 방제용 Je Yong Bang , 이창석 Chang Seok Lee

DOI:10.15681/KSWE.2015.31.6.680 Vol.31(No.6) 680-692, 2015

A landcover map watershed of downstream reach in the Gyungan stream was made by using the existing land use map and interpreting satellite images and aerial photos. Based on the map, we analyzed land use patterns of this basin. Broad-leaved forest occupied the largest area among landscape elements established in this watershed. The total area of the zone designated as the waterside district by the central government was 4.7 km2, and broad-leaved forest occupied the largest area as 33.9% in this zone. Therefore, the area did not meet the qualifications of riparian zones. Riparian vegetation established in the Gyungan stream watershed was composed of Phragmites communis, Miscanthus sacchariflorus, Salix gracilistyla, Salix koreensis. But terrestrial vegetation elements such as Ambrosia trifida, Ailanthus altissima, Robinia pseudoacacia also appeared in this area. On the other hand, Phragmites japonica, Salix gracilistyla, Salix koreensis, Salix integra, Ulmus davidiana and so on appeared in the riparian zone the reference streams. Differently from the vegetation established on the reference streams, terrestrial vegetation elements appeared frequently in the Gyungan stream watershed. This result would be due to that the Gyungan stream watershed is exposed to excessive human interferences.

Landscape structure, Land use type, Reference stream, Riparian vegetation

성윤수 Yunsoo Sung , 양재의 Jae E Yang , 김성철 Sung Chul Kim , 류지철 Jichul Ryu , 장원석 Wonseok Jang , 금동혁 Donghyuk Kum , 임경재 Kyoung Jae Lim

DOI:10.15681/KSWE.2015.31.6.693 Vol.31(No.6) 693-699, 2015

It has been known that torrential rainfall events have been occurring worldwide due to climate change. The accelerated soil erosion has caused negative impacts on water quality and ecosystem of receiving waterbodies. Since soil security issues have been arising in various areas of the world, intensive interests have been given to topsoil management in Korea. Thus in this study, Web GIS-based computing system of physical, chemical, and biological topsoil quality indices were developed. In this study, five soil quality maps at national scale and top soil erosion potential were prepared for evaluation of soil quality based on soil erosion potential. For this system, the open source Web GIS engine, OpenGeo, was used as core engine of the system. With this system, decision makers or related personnel in areas of soil erosion Best Management Practices (BMPs) would be able to find the most appropriate soil erosion BMPs based on soil erosion potential and soil quality at the area of interest. The Web GIS system would be efficiently used in decision making processes because of ease-of-use interface and scientific data used in this system. This Web GIS system would be efficiently used because this system could provide scientific knowledge to decision makers or stakeholders. Currently various BMP database are being built to be used as a decision support system in topsoil management and topsoil quality areas.

BMPs, Soil erosion, Soil quality, Web GIS

최옥연 Ok Youn Choi , 김기훈 Ki Hoon Kim , 한인섭 Ihn Sup Han

DOI:10.15681/KSWE.2015.31.6.700 Vol.31(No.6) 700-714, 2015

The characteristic of the water quality and pollutant discharge was analyzed at the units watershed of the total amount management in Han-river basin, and after classified in a similar area by multivariate statistical analysis, the main trend such as the water quality trend and pollutant discharge characteristic were analyzed. As a result of this study, the density of the pollutant at the unit watershed is not necessarily identified as discharge density, and the primary management watershed and targeted substances were analyzed depending on the operating status of the environmental infrastructure in watershed and the main pollution factor and discharge path per pollutants. As a result of cluster analysis, watersheds were classified into four groups according to discharge characteristics. It will be used when selecting target area of primary management that is appropriate to the characteristics of each river and establishing efficient water quality improvement plans.

Cluster analysis, Discharge load characteristics, Factor analysis, Pollution discharge, TMDLs, Unit watershed

김홍태 Hongtae Kim , 신동석 Dongseok Shin , 김현정 Hyeonjeong Kim , 최인욱 Inuk Choi , 이미선 Miseon Lee , 김용석 Yongseok Kim

DOI:10.15681/KSWE.2015.31.6.715 Vol.31(No.6) 715-722, 2015

Four major river basin in Korea has been managed with Total Maximum Daily Load(TMDL) System. Water quality indicators as targeted pollutants for TMDL were BOD and TP. In order to satisfy water quality criteria, government allocation using public treatment facilities and its action plan has been used. However, the role to improve water quality were recently faced to its limitation. It is time to require the role of non-government allocation in private discharge facilities to control good water quality. This study investigated three different scenarios in reduction demands of non-government allocations about industry and private sewages. The three different scenarios were discharge under 1) legal water quality standard, 2) water quality level in 2011 and 3) current water quality level with maximum value in group. The results showed that reduction potential in water discharge for TP indicator was 1,118kg/day, under second scenario with 20% of deduction. This results arrived at 42% of whole reduction potential costs and 0.012mg/L improvement in water quality. In conclusion, to intrigue voluntary participation in non-government allocation, various benefits such as tax reduction, tax exemption, and water quality trading should be provided.

Non-government allocation, Private discharge facilities, Reduction potential, Total Maximum Daily Load, TM이

나은혜 Eun Hye Na , 박수영 Suyoung Park , 김종하 Jongha Kim , 임성수 Seongsoo Im , 김경현 Kyunghyun Kim

DOI:10.15681/KSWE.2015.31.6.723 Vol.31(No.6) 723-731, 2015

We investigated the spatial and temporal patterns of water quality in the Gangjung-Goryoung weir that is located in the middle area of the Nakdong river, Korea. The monitoring results indicated that there are discernible vertical differences in water quality during the pre- and post-monsoon periods (May to September). During this period, it was observed that the weak thermal stratification formed at the maximum level, and pH, Chl-a, and DO concentrations in the surface layer were higher than those in the bottom layer. This vertical difference was especially noticeable for DO concentrations: there were DO depletions at the bottom layer in late June to early August. During the summer monsoon period with heavy rainfall, there was a decline in vertical differences in water quality. From this study, it was suggested that continuous monitoring of vertical profiles could become a useful tool for identifying the spatial and temporal distributions of water quality and for developing the best management policy for water quality in the Nakdong river.

Algal bloom, DO depletion, Gangjung-Goryoung weir, Nakdong river, Thermal stratification

김은경 Eunkyoung Kim , 류지철 Jichul Ryu , 김홍태 Hongtae Kim , 김용석 Yongseok Kim , 신동석 Dongseok Shin

DOI:10.15681/KSWE.2015.31.6.732 Vol.31(No.6) 732-738, 2015

Water quality in four major river basin in Korea was managed with Total Maximum Daily Load (TMDL) System. The unit watershed in TMDL system has been evaluated with Target Water Quality (TWQ) assessment using average water quality, without considering its volume of water quantity. As results, although unit watershed are obtained its TWQ, its allocated loads were not satisfied and vice versa. To solve these problems, a number of TWQ assessments with using Load Duration Curve (LDC) have been studied at other watersheds. The purpose of this study was to evaluate achievement of TWQ with Flow Duration Curve (FDC) and Load Duration Curve(LDC) at 26 unit watersheds in Han river basin. The results showed that achievement rates in TWQ assessment with current method and with LDC were 50~56 % and 69~73%, respectively. Because of increasing about 20% of achievement rates with using LDC, the number of exceeded unit watershed at Han river Basin was decreased about 4~6 unit watersheds.

Han-River, LDC, Load Duration Curve, Target Water Quality, TMDLs, Total Maximum Daily Loads