Franz Kevin F. Geronimo , Marla C. Maniquiz-redillas , 홍정선 Jungsun Hong , 김이형 Lee-hyung Kim

DOI:10.15681/KSWE.2017.33.1.1 Vol.33(No.1) 1-7, 2017

Bioretention systems, an advance low impact development and green infrastructure approach were currently utilized in different parts of the world because it promotes biodiversity thereby mimicking and preserving the pre-developed state of an area. This study investigated and compared the capability of four bioretention systems to identify factors affecting the hydraulic capabilities and pollutant removal efficiencies of each system. The two bioretention type A referred as Type A-C and Type A-FC were planted with perennials such as Chrysanthemum and Fan columbine, respectively. On the other hand, the two type B bioretention systems referred as Type B-A and Type B-JM were planted with shrub plant species such as Azalea and Japanese Meadowsweet, respectively. Based on the results, TV, infiltration mechanism, filter media depth and plant species were identified as the factors affecting the difference in flow attenuation, retained volume and pollutant removal efficiency of Type A-C, Type A-FC, Type B-A and Type B-JM bioretention systems. The design of bioretention Type B-A and Type B-JM were advantageous considering greater volume retention, groundwater recharge, longer HRT and peak flow attenuation and greater pollutant removal efficiency. On the other hand, the design of bioretention Type A-C and Type A-FC was more appropriate for design considering reduced groundwater contamination.

Bioretention, Event mean concentration, Flow attenuation, Green infrastructures, Low Impact Development

최희정 Hee-jeong Choi

DOI:10.15681/KSWE.2017.33.1.8 Vol.33(No.1) 8-14, 2017

Microcystis aeruginosa (M. aeruginosa) is a cyanobacterium species that can form harmful algal blooms in freshwater bodies worldwide. The use of pine needle extract (PNE) to control nuisance algae by allelopathic inhibition will be environmentally friendly and promising. PNE successfully removed up to 98% of M. aeruginosa at the following optimal conditions: pH 7, 25 °C, 100 rpm of mixing rate, 5 min of mixing time. These results indicated that 1 g/L PNE was removed 1g dry weight/L of M. aeruginosa. The kinetic data showed that substrate inhibition kinetics and maximum growth rate were obtained when the M. aeruginosa was grown in a medium containing 0.5 g/L of initial concentration of PNE. Different substrate inhibition models were fitted to the kinetic data; the Luong model was found to be best. The model-predicted kinetic parameters were in agree-ment with the experimental findings. The natural extract, PNE, can be a promising inhibition because its high efficiency and low dose requirements.

Algal blooms, Cyanobacterium, Inhibition, M. aeruginosa, Pine needle extract, Water treatment

최옥연 Ok Youn Choi , 김홍태 Hong Tae Kim , 서희승 Hee Seung Seo , 한인섭 Ihn Sup Han

DOI:10.15681/KSWE.2017.33.1.15 Vol.33(No.1) 15-33, 2017

Based on the existing pollutant emission standards which are armed at the pollutant concentration of each pollution source, the government formulated and implemented a new management system of total water-pollutant emission. By virtue of this new management system, pollution-loading amount of individual watershed could be controlled, which achieved the requirements of water-quality management, such as TP and BOD. In initiate stage of its implementation, BOD was selected as the object of water-quality management, since we need to consider the continuity of water-quality data and established pollutant-management laws and policy. During the ongoing management, TP management was added into the system, since BOD management alone was not enough. However, the frequency of algae bloom in Han river showed the same trend, even though TP was treated as additional control target. Therefore, this paper will analyze different water-quality parameters and characteristic of water quality, in order to serve as a reference for watershed management of water quality, by which the applicable management period and target pollutant can be selected in the future.

Han river, Mann-kendall test, Nonparametric trend analysis, Seasonal Mann-kendall test, TMDLs

김다은 Da-eun Kim , 유재민 Jaemin Yoo , 이용호 Yongho Lee , 박대원 Daewon Pak

DOI:10.15681/KSWE.2017.33.1.34 Vol.33(No.1) 34-39, 2017

Under a corrosive environment, electrodes that are applied in the water-treatment system need not only very high electro-chemical activity for fast reaction, but also high durability for cost saving. Therefore, fabrication condition of iridium electrodes was examined to produce a more durable iridium electrode in this study. Tantalum was selected as a binder to enhance the durability of the iridium electrode. Investigation on the weight ratio between the catalyst and the binder to improve electrochemical activity was performed. Also, to compare the effect of the different coating amount of the catalyst, the result of CV (Cyclic Voltammetry) and EIS (Electrochemical Impedance Spectroscopy) were discussed. Furthermore, ALT (Accelerated Lifetime Test) was designed and applied to the electrodes to determine the conditions for highly durable electrode fabrication.

Accelerated lifetime test, Catalytic electrode, Cyclic Voltammetry, Electrochemical characterization, Electro-chemical Impedance Spectroscopy

김미아 Mi-ah Kim , 이소영 Soyoung Lee , 문현생 Hyunsaing Mun , 조항수 Hang-soo Cho , 이재관 Jae-kwan Lee , 김경현 Kyunghyun Kim

DOI:10.15681/KSWE.2017.33.1.40 Vol.33(No.1) 40-50, 2017

We were interested in the long-term temporal and spatial variability trends of water quality. Trend tests, such as the Seasonal and Regional Kendall tests and LOWESS (LOcally WEighted Scatter-plot Smoother), have been recommended as outstanding tools for trend detection. In this study, we conducted four types of nonparametric trend tests (Seasonal and Regional Kendall tests, LOWESS, and flow-adjusted Seasonal Kendall). We aimed to identify water quality trends using the monthly data for five variables (BOD, COD, TN, TP, and flow) collected from 24 sites in the Nakdong River from August 2004 to December 2013. According to the Regional Kendall test, BOD, COD, and TN increased but TP decreased trend. The Seasonal Kendall test showed that BOD, TN, and TP remained constant at 62.5-83.3% of the sites. COD remained constant at 58.3% of the sites. LOWESS showed that TP gradually increased between 2007 and 2008, then decreased slowly at the Gumi, Geumhogang6, Daeam-1 and Milyanggang3 sites. BOD increased slightly between 2008 and 2009, and then decreased slowly at the Namgang4-1 site. Lastly, a flow-adjusted Seasonal Kendall test was conducted. There were different results from the Seasonal Kendall and flow-adjusted Seasonal Kendall tests at 11 of the 24 sites. According to the results from six of the eleven sites, BOD increased at one site, showed no trends at three sites, and decreased at two sites. Each of COD, TN increased at two, and one site. but TP decreased at two sites.

Flow-adjusted Seasonal Kendall, LOWESS, Nakdong river, Seasonal and Regional Kendall

김경훈 Gyeonghoon Kim , 권헌각 Heongak Kwon , 임태효 Taehyo Im , 이규동 Gyudong Lee , 신동석 Dongseok Shin , 나승민 Seungmin Na

DOI:10.15681/KSWE.2017.33.1.51 Vol.33(No.1) 51-62, 2017

The purpose of this study is to evaluate on the applicability of the Load Duration Curve (LDC) method using a Maintenance of Variance Extension type 2 method and sampling data for efficient total maximum daily loads at the Nakbon-A unit watershed in Korea. The LDC method allows for characterizing water quality data, such as BOD, TOC, T-N and T-P in this study at different flow regimes (or quarters). BOD usually exceeded the standard value (probability 50%) at the low flow zone. On the other hand, TOC, T-N, and T-P usually exceeded the standard value at the dry and low flow zone. Seasonally, all water-quality variables usually exceeded the standard value at Q1 (Jan-Mar) and Q2 (Apr-Jun) zones. Improvement of effluent control from wastewater-treatment plants are effectively improves BOD and T-P.

Extension method, FDC, LDC, MOVE.2, TMDLs

최유현 Yoo Hyun Choi , 주현종 Hyun Jong Joo

DOI:10.15681/KSWE.2017.33.1.63 Vol.33(No.1) 63-69, 2017

Small, privately owned wastewater-treatment plants have had a problem in treating their wasted sludge and maintaining steady effluent quality as compared with publicly owned wastewater-treatment plants. Therefore, this study has focused on how to improve treatment efficiency, specially nitrogen removal efficiency, by recycling filtrate as an alkalinity additive from filter press using CaCO₃. It was found that the optimal mixing ratio between the excess sludge and the CaCO₃ was 1:2. The major operation parameters, such as specific substrate utilization rate, specific nitrification rate, and specific denitrify-cation rate, were also improved by 64% (0.048-0.079 mg BOD₅/mg MLVSS·day), 35% (0.020-0.027 mg NH₃-N/mg MLVSS·day) and 68% (0.051-0.086 mg NO₃^--N/mg MLVSS·day), respectively, after the adoption of new methods. Therefore, both the problem of sludge treatment at small scale plants and the need for efficiency efficiency could be solved.

Advanced Treatment Process, CaCO₃, Dewatering Sludge, Filter Press

황하선 Ha Sun Hwang , 박지형 Ji Hyung Park , 김용석 Yong Seok Kim , 류덕희 Doug Hee Rhew , 최유진 Yu Jin Choi , 이성준 Sung Jun Lee

DOI:10.15681/KSWE.2017.33.1.70 Vol.33(No.1) 70-77, 2017

Total Pollution Load Control (TPLC) is a system for managing the discharge load assigned by satisfying the Water Quality (TWQ) in Standard Flow Conditions (SFC). TWQ between Metropolitan Cities/Dos Specified (Cities/Dos TWQ) is very important as the basis for each Unit Watershed TWQ. The purpose of this study was to establish a rational and scientific "Calculation Method for Cities/Dos TWQ." A methodology for the third-phase Cities/Dos TWQ was proposed in this study based on review of the past phases (first and second) Cities/Dos TWQ in the Nakdong river basin. The water-quality model was used to estimate the third-phase Cities/Dos TWQ. The allocation methods of individual discharge sources are important for estimating Cities/Dos TWQ In this case, the key point of the method of calculating the total allowable individual sources is the balance of the equity and the efficiency between individual sources of reduced pollutants. Thus, water quality should be determined for the current emission levels, the reduction capacity, and the technical possibilities of individual sources. We estimate the third-phase Cities/Dos TWQ according to the ` Calculation Method of Cities/Dos TWQ`.

Boundary between Metropolitan Cities/Dos Specified, Nakdong River Basin, Target Water Quality (TWQ), Total Pollution Load Control (TPLC)

안정민 Jung-min Ahn , 정강영 Kang-young Jung , 김신 Shin Kim , 이혜진 Hae-jin Lee , 신석호 Suk-ho Shin , 양득석 Duk-seok Yang , 신동석 Dongseok Shin , 나승민 Seung-min Na

DOI:10.15681/KSWE.2017.33.1.78 Vol.33(No.1) 78-89, 2017

Water quality monitoring network data is being affected continuously due to non-point source pollution arising from agricultural land located on the Gwangsancheon outlet in the Nakdong River basin. In this study, we have performed analysis of water quality monitoring system, water quality pattern using SOM and water quality in the Gwangsancheon for sub-basin located at Gisan-myeon in the Nakdong River basin. We developed and applied the model to estimate the runoff and non-point source loading. As a result of SOM pattern, the effect of non-point source pollution was the largest in the paddy fields and fields. As a result of the developed model, we found contribution rate and reduction rate for non-point source loading according to change of landuse because the reduction effect of nonpoint pollutants was 20.9% of SS, 9.9% of TN, 21.2% of TP and 8.9% of TOC depending on the landuse change.

EMC, Gwangsancheon, Non-point source loading, Runoff

장희선 Hee-seon Jang , 이호식 Ho-sik Lee

DOI:10.15681/KSWE.2017.33.1.90 Vol.33(No.1) 90-96, 2017

Many sewage-treatment plants have applied the advanced technology of chemical coagulant system to remove phosphorus in Korea. However, there are some problems with the injection of optimum coagulant dosage. In order to solve these problems, research on the more cost-effective automatic total phosphorus coagulation control system using an EC (Electrical Conductivity) has been in progress. This study was conducted by the same process and operation method as the Lab scale for public, small-town sewage-treatment plants. First, it confirmed the correlation among the EC, PO₄-P, and coagulant dosage in the Lab-scale MSBR (Membrane Sequencing Batch Reactor) process. Next, it found the correlation coefficient of EC and the coagulant dosage was 0.92 in the Full-scale MSBR process. As a result, not only was the T-P removal efficiency doubled, but the process also it satisfied the effluent water-quality standard in a stable manner. In addition, by applying the automatic control system using the EC, the coagulant dosage could be reduced by 28% compared to the fixed coagulant injection system.

Automatic Control System, Coagulant Dosage, EC, MSBR, Phosporus

신민환 Minhwan Shin , 전지홍 Ji-hong Jeon

DOI:10.15681/KSWE.2017.33.1.97 Vol.33(No.1) 97-106, 2017

In this study, the characteristics of nonpoint source pollutant loads from separate sewer overflow (SSO) and combined sewer overflow (CSO) were evaluated during 2016 in Namyangju city, Korea. Five rainfall events were monitored during 2016 with ranging from 14.5 mm to 121.5 mm. The runoff ratio of CSO was higher than that of SSO because only design volume of maximum sanitary sewer (1Q_h) was transported and treated and 2Q_h was overflowed to waterbody during rainy day although combined sewer system was designed to transport 3Q_h to treatment system. The event mean concentrations (EMCs) and pollutant loads from CSO were higher than those from SSO. BOO and COD of CSO, and TOC and TN of SSO represented distinct first flush phenomena. The inadequate management in combined sewer system from which the untreated 2Q_h from CSO was overflowed to waterbody during rainy day could influence on high pollutant loads and first flushing. Treating 2Q_h from CSO, source control such as low impact development, and treating outflow from SSO were strongly recommended to control non-point source pollution in urban area.

Combined sewer system, Nonpoint source pollution, Separate sewer system, Urban runoff