박선구 Park Seon Gu , 임연택 Im Yeon Taeg

DOI: Vol.20(No.2) 93-103, 2004

원성연 Won Seong Yeon , 이상일 Lee Sang Il

DOI: Vol.20(No.2) 104-109, 2004

Removal of nutrients from domestic sewage or industrial wastewater is needed to protect surface waters from eutrophication. This research was carried out to remove the nitrogen (N) and phosphorus (P) from the wastewater using the iron oxide obtained from the steel industry and the natural zeolite, respectively. This research was conducted in both batch and continuous systems. The removal efficiency of the nutrients was evaluated in the batch system using the varying concentrations of zeolite and iron oxide added. The removal efficiency of N was 60% at the 8g of zeolite added. In the same condition, the removal efficiencies of N were 76% and 82% at 12g and 16g of zeolite added, respectively. Removal efficiency of P was 80% as 8g of iron oxide was added. The removal efficiency of P was correspondingly increased as the concentration of iron oxide was increased. Continuous column system was also used to evaluate the removal efficiency of N and P by the addition of zeolite and ferric oxide, respectively. Removal efficiencies of N were compared in the mixed packing, two stage, and four stage columns, respectively. The removal efficiencies (80%) of N in the separate packed columns (two and four stages) were higher than the mixed packing column (400%) after 90 hr. Whereas, the removal efficiencies of P were similar to each other in the three columns.

Zeolite, Iron Oxide, Nitrogen, Phosphate

최용수 Choe Yong Su , 홍석원 Hong Seog Won , 권기한 Kwon Gi Han , 정일호 Jeong Il Ho

DOI: Vol.20(No.2) 110-119, 2004

The combination of biological and physical/chemical technologies is a promising technique to reduce highly concentrated pollutants in livestock wastewater. It is suggested to treat livestock wastewater efficiently as follows: firstly, biodegradable organic matters, nitrogen and some of phosphorus should be removed by a biological treatment process and then residual non-biodegradable organic matters, color and phosphorus be eliminated by physicochemical technologies. In this study, therefore, the integrations of chemical coagulation, activated carbon adsorption, Fenton oxidation and ozonation were evaluated to provide appropriate post-treatment processes for biologically pretreated livestock wastewater. After chemical coagulation followed by ozonation or Fenton oxidation process, the quality of treated wastewater could meet the discharge limit in Korea. However, a yellowish brown color still remained in the treated wastewater after a single method such as coagulation and Fenton oxidation was applied. The ozonation was found to be the most effective technology for the decolorization. Neither simple biological nor physicochemical treatment provides adequate decolorization and sufficient depletion of organics in livestock wastewater so far. Consequently, the integration of Fenton oxidation and ozonation with a biological treatment process is recommended to treat livestock wastewater in terms of removal efficiency.

Biologically Pre-treated Livestock Wastewater, Color, Non-biodegradable Organic Matters, Phosphorus, Physicochemical Technologies

신혜숙 Sin Hye Sug , 김희갑 Kim Hui Gab

DOI: Vol.20(No.2) 120-125, 2004

Exposure to volatile disinfection by-products (DBPs) such as chloroform included in chlorinated tap water can occur during household activities via inhalation as well as ingestion and dermal absorption. This study was conducted to examine the significance of inhalation route of exposure since humans are unintentionally exposed to volatile DBPs while staying home. Two sets of experiments were carried out in an apartment to measure: 1) the variation of chloroform concentrations in the living room air following kitchen activities (cooking and dish-washing); and 2) the variation of chloroform concentrations in the bathroom and living room following showering. Cooking, dish-washing, and showering all contributed to the elevation of household chloroform levels. Even a few minutes of natural ventilation resulted in the reduction of the chloroform levels to the background. Estimates of daily chloroform doses and lifetime cancer risks suggested that inhalation of household air during staying home be a major route of exposure to chloroform and that ingestion be a minor one in Korean people. It is also suggested that ventilation be a simple and important measure of mitigating human exposure to volatile DBPs indoors.

Chlorinated Tap Water, Chloroform, Cooking, Dish-washing, Disinfection by-products, Inhalation, Shower

Yoon Jin Lee , Sang Ho Nam , Byong Ho Jun , Kyoung Doo Oh , Suk Bong Kim , Jae Keun Ryu , Dionysios D. Dionysiou , Sadahiko Itoh

DOI: Vol.20(No.2) 126-131, 2004

This research sought to compare chlorine, chlorine dioxide and ozone as chemical disinfectants of drinking water, with inactivation of total coliform as the indicator. The inactivation of total coliform was tested against several variables, including the dose of disinfectant, contact time, pH, temperature and DOC. A series of batch processes were performed on water samples taken from the outlet of a settling basin in a conventional surface water treatment system that is provided with the raw water drawn from the mid-stream of the Han River. Injection of 1 ㎎/L of chlorine, chlorine dioxide and ozone resulted in nearly 2.4, 3.0 and 3.9 log inactivation, respectively, of total coliform at 5 min. To achieve 99.9 % the inactivation, the disinfectants were required in concentrations of 1.70, 1.00 and 0.60 ㎎/L for chlorine, chlorine dioxide and ozone, respectively. Bactericidal effects generally decreased as pH increased in the range of pH 6 to 9. The influence of pH change on the killing effect of chlorine dioxide was not strong, but that on ozone and free chlorine was sensitive. The activation energies of chlorine, chlorine dioxide and ozone were 36,053, 29,822 and 24,906 J/㏖ for coliforms with inactivation effects being shown in the lowest orders of these.

Chlorine, Chlorine Dioxide, Ozone, Disinfection, Factors, Drinking Water Treatment

이두진 Lee Du Jin , 신응배 Sin Eung Bae , 홍철의 Hong Cheol Ui , 안세영 An Se Yeong

DOI: Vol.20(No.2) 132-144, 2004

The purpose of this study was to evaluate alternatives for stable operation of WWTP(Wastewater Treatment Plant) with a higher rate of inflows and a higher concentration of pollutants during wet weather to minimize the pollution loads being discharged into receiving waters. 3Q(Q: dry weather flow) of a base flow is normally intercepted and flows into WWTP as it was current practice. It is revealed by simulation that the bypassing alternative of 1Q through secondary treatment and 2Q into the stream after primary treatment was as good as it is expected. The bypass pollution loads were in the range of 23.9 - 38.5% of the total loads flowing into the WWTP indicating that the bypassed flows need an extra treatment such as stormwater detention reservoir, high-rate coagulation with sedimentation, and step-feed. The high-rate coagulation with sedimentation was the most effective with respect to removal of the pollution loads.

3Q, Bypass, Stormwater Detention, Hihg-rate Coagulation/Sediment, Step-feed

김경숙 Kim Gyeong Sug , 오병수 O Byeong Su , 주설 Ju Seol , 강준원 Kang Jun Won

DOI: Vol.20(No.2) 145-150, 2004

This study investigated the effect of chlorine dose and chlorine reaction time for the formation of haloacetic acids (HAAs). According to the results, HAA formation was highly affected by chlorine dose and chlorine reaction time. HAA formation reached a plateau value at 30 ㎎/L of chlorine dose and 24 hr of chlorine reaction time. For the speciation of formed HAAs in the test water, the concentration of brominated-HAAs was significantly lower than that of chlorinated-HAAs because of low level of bromide ion concentration in the test water. It also investigated the removal efficiency of HAA precursors by several unit processes, such as ozone alone, UV alone, and combined ozone/UV system. Of them, ozone/UV system was proved as the best process to control the HAAs formation. The increase of the brominated-HAAs was observed during ozonation with and without UV irradiation showing the slight increase of total HAA concentrations.

Haloacetic Acids, Speciation, Ozone, UV, Ozone/UV

이혜영 Lee Hye Yeong , 박석순 Park Seog Sun

DOI: Vol.20(No.2) 151-156, 2004

A decision support system, Watershed Analysis Risk Management Framework(WARMF), was applied to the Kyungan Stream watershed, a tributary of Lake Paldang, for calculation of total maximum daily loads(TMDL). The WARMF system was developed by Systech Engineering, USA, and has been successfully used in several watersheds, for TMDL studies. The study area was divided into 14 sub-basins, based on digital elevation model(DEM). The integrated watershed and stream model of WARMF was validated by flow and BOD data measured during the year of 1999. There were reasonable agreements between model results and field data, both in water flow and BOD. The validated Kyungan WARMF was extensively utilized to study the quantitative relationship between waste loads and receiving water quality. Based on TMDL guideline at Paldang Lake and Kyungan Stream, the water quality criterion were set to be 3.0㎎/L, 3.5㎎/L, and 4.0㎎/L at the watershed outlet. The allowable waste loads of BOD, both from point and non-point sources, were determined at each water quality criterion. From this study, it was concluded that the WARh4F provided several advantages over the conventional application of watershed and stream models for TMDL study, such as time variable simulations, multiple possible soutions, and reduction loads for goal water quality, etc.

Total Maximum Daily Loads, Water Quality Model, Decision Support System, Waste Loa d Allocation, WARMF, Kyoungan Stream

박재홍 Park Jae Hong , 최의소 Choe Ui So , 조일형 Jo Il Hyeong

DOI: Vol.20(No.2) 157-162, 2004

Constructed wetlands are considered as an important tool for wastewater treatment, wastewater management and flooding control. In addition, one of the most promising technologies for application in many countries seems to be constructed wetlands, due to their properties such as utilization of natural processes, simple construction, operation and maintenance, process stability, cost effectiveness, etc. This study considered possibility of treatment of livestock wastewater using a constructed wetland. The removal efficiencies of COD_(cr), TOC, TN, TP, SS, and color were 97.6%, 96.6%, 97.0%, 96.7%, 99.0%, and 85.6%, respectively. In particular, SS was completely removed. However, Cl^(-) concentration of the constructed wetland effluent was higher than that in influent. In conclusion, constructed wetlands could be applied to livestock wastewater treatment if Cl^(-) would be properly treated. Further, it needs time for stabilization to reduce the pollutants which were accumulated in soil.

Constructed Wetland, Livestock Wastewater, Nutrient Removal

김석구 Kim Seog Gu , 정장식 Jeong Jang Sig , 곽필재 Gwag Pil Jae , 최준향 Choe Jun Hyang , 이현동 Lee Hyeon Dong , 이태윤 Lee Tae Yun

DOI: Vol.20(No.2) 163-169, 2004

Feasibility of using PE sheet laminated CSP(Corrugated steel pipe) to sewers were tested via corrosion and abrasion tests for PE sheet laminated CSP; 1) corrosion test for PE film and PE coated plate, 2) corrosion test for joint of PE sheet laminated CSP, 3) corrosion test for outside of PE sheet laminated CSP, and 4) abrasion test for inside of PE sheet laminated CSP. The results for the corrosion and abrasion tests are as follows. 1. Results for corrosion tests on PE films and zinc coated steel plates that were coated with PE films show that the surfaces of both PE were not changed compared to those of original PE samples. Furthermore, PE films maintained strong adhesion on the steel plates even though they were exposed to sewage and seawater provided cutting planes of the steel plates were treated with molding. But, results for corrosion tests on the spots that were previously cut off by a knife and a cutting planes of the steel plates were treated without molding show that steel plates have been corroded if they were exposed to sewage and seawater. 2. Results for corrosion tests on joints of PE sheet laminated corrugated steel using sewage show that gathering rust was observed at cutting plane of PE sheet laminated corrugated steel after 180 days, but PE film was not flaked off. However, PE film at cutting plane was flaked off when PE sheet laminated corrugated steel was exposed to seawater. Furthermore, flaking process was severely progressed at lockseam points of which the surfaces were not smooth. 3. Results for laying PE sheet laminated corrugated steel under the ground show that the surface of untouched PE film was almost identical to that of original PE film. However, the spots that were previously cut off by a knife and a cutting plane of PE sheet laminated corrugated steel have flaked off. 4. As a result of abrasion tests conducted with PE sheet laminated corrugated steel and sand, brilliance and thickness of PE was not greatly changed under the severe abrasion conditions. Therefore, the durability of PE sheet laminated corrugated steel for abrasion was determined to be good.

Abrasion, Corrosion, PE sheet laminated CSP, Corrugated steel pipe

오병수 O Byeong Su , 주설 Ju Seol , 김경숙 Kim Gyeong Sug , 강태희 Kang Tae Hui , 이지영 Lee Ji Yeong , 이혜영 Lee Hye Yeong , 강준원 Kang Jun Won

DOI: Vol.20(No.2) 170-175, 2004

The purpose of this study was to monitor bacteria present in raw water and to investigate the effect of ozone, UV and combined ozone/UV processes for inactivating bacteria. Both polymerase chain reaction (PCR)-fragment length polymorphic analysis (PRA) and PCR-sequence analysis (PSA) were applied for the simultaneous analysis of numerous bacteria species present in each tested water, such as drinking water (DRW), drinking water source (DRWS) and sewage effluent water (SEW). According to the result, the number of detected bacteria species was zero in DRW, 58 in DRWS and 13 in SEW. After treatment of the each process, the ozone/UV process was the most successful for inactivating almost all bacteria. However, it was found that Flavobacterium sp., Pseudomonas sp. and Beta proteobacterium sp. had strong resistant to all tested processes, requiring further detailed study.

Bacteria, PCR, Monitoring, Inactivation, Ozone, UV

송승주 Song Seung Ju , 오병수 O Byeong Su , 나승진 Na Seung Jin , 이응택 Lee Eung Taeg , 강준원 Kang Jun Won

DOI: Vol.20(No.2) 176-182, 2004

The purpose of this study was to investigate the heterogeneous catalytic ozonation of oxalic acid by manganese (Mn) doped-granular activated carbon (GAC). In order to observe the effect of the amount of Mn doped on GAC, catalysts were manufactured by varying the impregnated Mn concentration. In this paper, the following had labeled all sorts kinds of Mn-doped GAC were labeled with suitable names according to the amount (mM) of the concentration of dipping solution: They were each named as `Mn20`, `Mn50`, `Mn100` and `Mn200`. These experiments were performed in a batch reactor (0.5 L) and a semi-batch reactor (1L) and Mn-free GAC was used as a blank catalyst. The ozone decay properties of each manufactured catalyst were firstly investigated to find out the reactivity between the aqueous ozone and the catalysts. Oxalic acid removal by catalytic ozonation was then performed to demonstrate the oxidative efficiencies of each catalyst.

Catalytic Ozonation, Mn-doped GAC, Ozone, Catalysts, Oxalic Acid

김종오 Kim Jong O , 김석구 Kim Seog Gu , 김이호 Kim I Ho

DOI: Vol.20(No.2) 183-189, 2004

The performance of a membrane-coupled anaerobic fermenter system for the recovery of volatile fatty acids (WAS) from liquid organic sludge was experimentally investigated. Permeation flux was stably kept around 0.2 (㎥/㎡/day) during operational period. The membrane-coupled fermenter showed 2.2 times higher VFAs concentration and higher VFAs forming rate than those of fermenter without membrane. The fermenter with membrane proved to be an effective system for the recovery of soluble organic materials from liquid sludge.

Membrane, Liquid organic sludge, VFAs, Fermenter

김응호 Kim Eung Ho , 조연제 Jo Yeon Je , 박성주 Park Seong Ju , 신광수 Sin Gwang Su , 임수빈 Im Su Bin , 정진권 Jeong Jin Gwon

DOI: Vol.20(No.2) 190-195, 2004

A new technology for advanced wastewater treatment was developed using a modified Rotating Biological Contactor (RBC) process, named as Rotating Activated Bacillus Contactor (RABC) process that utilizes Bacillus sp., the facultatively anaerobic or activated microaerophilic bacteria on multiple-stage reticular rotating carriers, as a predominant species. The RABC process for a municipal wastewater with relatively low concentrations of organics, nitrogen, and phosphorus showed stable and high removal efficiencies, less than BOD_(5) 10 ㎎/L, T-N 15 ㎎/L, and T-P 1.5 ㎎/L in final effluent. The performance load of RABC process was shown to be 1.23 ㎏·BOD/㎡·day for the first stage (average 0.31 ㎏·BOD/㎡·day for the total stages) based on both removed BOD and converted disc area corresponding to the reticular one. The sludge produced in the RABC process is characterized by low generation rate (about 0.18㎏·MLSS/㎏·BOD) and excellent settleability. The number ratio of Bacillus (2.4×10(6)) CFU/ml) to heterotrophic bacteria ( 3.6×10_(7) CFU/ml) inhabiting in the biofilms of the RABC process was 6.7%, indicating that Bacillus sp. was a predominant species in the biofilms. The RABC process with reticular rotating carriers showed its excellent performance for the advanced wastewater treatment without any offensive odor problem due to organic overloading.

Advanced Wastewater Treatment, Bacillus sp., Nitrogen, Phosphorus, Rotating Activated Bacillus Contactor, RABC, Process