James C . Young , In S . Kim

DOI: Vol.14(No.1) 1-12, 1998

Anaerobic processes have become attractive alternatives to aerobic processes for treating moderate to high-strength industrial wastewater. While there are no definitive guidelines for process selection, aerobic processes generally are more appropriate for treating wastewaters containing chemical oxygen demand concentrations (COD) less than about 3,000㎎/L or biochemical oxygen demand (BOD) concentrations less than about 2,000㎎/L. In this paper, important parameters such as organic loading rate, F/M ratio, biomass concentration, and overall COD removal efficiency for internationally patented processes (Upflow Fully Packed Anaerobic Filter, Upflow Hybrid Anaerobic Filter, Two-Stage Fixed Media System, Downflow Anaerobic Filter, Upflow Sludge Blanket Reactor, Anaerobic Fluidized Bed Reactor, and Thermophilic Fixed-Film Reactor) are analyzed and discussed. Detailed discussions are also made on the factors affecting the design and operation of these anaerobic systems.

김동현 , 이경혁 Dong Hyun Kim , Kyung Hyuk Lee

DOI: Vol.14(No.1) 13-19, 1998

Degradation of organic chemicals in organic acid cleaning reagent using Fenton oxidation was demonstrated. The optimum conditions for Fenton oxidation of organic acid cleaning reagent were determined; pH of solution was 3.5, the concentration of ferrous ion (Fe(Ⅱ)) was 90mM, and the ratio of ferrous ion to hydrogen peroxide (H₂O₂) was 1:4.9(mM:mM). Under the optimum conditions of Fenton oxidation, the concentration of total organic carbon (TOC) of organic acid cleaning reagent decreased from 8668ppm to 5585ppm after Fenton oxidation and the reaction was completed within or less than 10 minutes. When Fenton oxidation was performed, the concentration of TOC of organic acid cleaning reagent became 3593ppm and 2678ppm after the second and the third Fenton oxidation, respectively. The components, hydroxy acetic acid and thiourea, of organic acid cleaning reagent were difficult to be degraded, on the other hand, formic acid, triton X-100, and sorbic acid were easily degraded by Fenton oxidation.

정금희 , 손정희 , 박종복 , 이용희 Keum Hee Jung , Jung Hee Shon , Jang Bok Park , Yong Hee Lee

DOI: Vol.14(No.1) 21-28, 1998

Nitrogen removal study of municipal wastewater was carried out in A City`s Wastewater Treatment Plant with dual sludge system. The dual sludge system consists of anoxic tank, oxic tank, and clarifier followed by Modified Ludzack-Ettinger(MLE) system. For nitrogen removal, methanol was used as an external carbon source in the anoxic tank. This process showed the effluent quality, achieving 81% of COD_(Cr), removal and 71% of total nitrogen removal. Influent wastewater contained 199∼548㎎/l of COD_(Cr), and 51∼83.8㎎/l of total inorganic nitrogen. The final effluent contained 42∼150㎎/l of COD-Cr and 11.2∼33.5㎎/l of total nitrogen. The specific denitrification rate and C/N ratio in the anoxic tank were 0.1∼0.34 (gNO₃-N/gVSS/d) and 3.06∼4.64 (gCOD consumed/gNO₃-N removed), respectively, at the range of 4∼14℃ of temperature.

임연택 , 서정범 , 유재근 Yeon Taek Rim , Jeong Beom Seo , Jae Keun Ryu

DOI: Vol.14(No.1) 29-35, 1998

Treatability and pressure difference in ultrafiltration was investigated in sequential anaerobic/aerobic activated sludge wastewater treatment system. Ultrafiltration had advantages for sludge separation than secondary sludge settling tank in biological wastewater treatment system. Clean and steady water quality in effluent was achieved but the flux was decreased with the lapse of time. Accordingly, the influence of control parameters of backwashing intervals and various loading rate to treatment efficiency and pressure difference to sustain steady flux were studied for the combination process of activated sludge and ultrafiltration membrane. The effluent BOD concentration showed less than 2㎎/l and T-N resulted in 11.5∼21.2㎎/l in this system. When organic loading rate was 0.5㎏BOD/㎥·d with less than 0.04㎏/c㎡ pressure difference the system could be controlled to sustain 0.2㎥/㎡·d flux. Specifically, hydrophilic membrane showed less than 0.02㎏/c㎡ pressure difference. Flux of 0.2㎥/㎡·d required 0.04㎏/c㎡ pressure difference but higher pressure difference was required to raise flux. Outside pressure infiltration and suction infiltration were compared. 0.25∼0.35㎏/c㎡ pressure difference was required to earn 0.2㎥/㎡·d of flux for outside pressure infiltration but only 0.04㎏/c㎡ pressure difference was required for the same flux of in the case of suction infiltration. In conclusion, there were no difference in effluent water quality between filtration by hydrophobic membrane and hydrophilic membrane but lower pressure difference was required by hydrophilic membrane to earn steady flux rate. When flux and organic loading rate in the reactor was raised, the required pressure difference was dramatically increased. In the case of longer backwashing intervals pressure difference tends to build up.

이광현 Kwang Hyun Lee

DOI: Vol.14(No.1) 37-45, 1998

The performance of two module sets with the variation of pH was compared and determined. The permeate flux of two module sets was increased with the increment of TMP and energy consumption per membrane surface area on the whole range of pH. Permeabilities for linear and helical modules of first module set compared to D.I. water permeability were increased about 20% and 11% at pH 3.18, but decreased about 60%`s at pH 9.11 respectively. Permeabilities for linear and helical modules of second module set compared to D.I. water permeability were increased about 40% and 31% at pH 2.94, but decreased about 47% and 58% at pH 8.56 respectively. The highest permeabilities for the linear and helical module of first module set at pH 3.18 showed about 199% and 174% increment compared to lowest values at pH 9.11. The highest permeabilities for the linear and helical module of second module set at pH 2.94 showed about 163% and 212% increment compared to lowest values at pH 8.56. From these, pH is the variable which effects membrane performance.

최돈혁 , 강호 Don Hyeok Choi , Ho Kang

DOI: Vol.14(No.1) 47-56, 1998

15 Aerators were constructed in Kwangdong Dam and Dalbang Dam to solve the ordor problem caused by algae and heavy metals, such as Fe and Mn. There for this study was carried out to investigate the effect of aeration on the water quality, species of plankton and the major environmental factors for algal growth. The results showed that the thermal stratification was destroyed and pH was decreased by the successful operation of aerators for one month in both lakes. COD and Chl-a were increased by applying aeration in Kwangdong Dam, a shallow lake while these were decreased in Dalbang Dam, a deep lake. For the case of dominant species of phytoplankton, Chlorophyta was replaced to Bacillariophyceae in Kwangdong Dam and Cyanophyta was replaced to Bacillariophyceae in Dalbang Dam, respectively. Correlation analysis between algal growth and environmental factors indicated that Cyanophyta and Bacillariophyceae correlated in opposition with dissolved inorganic phosphorus(DIP) in Kwangdong Dam, while in Dalbang Dam, Cyanophyta and Bacillariophyceae correlated in opposition with Temperature. However Cyanophyta correlated with total phosphorus and Bacillariophyceae with DO.

이해일 , 부경민 , 최명원 , 김창원 Hae Ill Lee , Kyung Min Bou , Myung Won Choi , Chang Won Kim

DOI: Vol.14(No.1) 57-64, 1998

Submerged Aerobic Biofilm Reactor(SABR) with series was investigated for wastewater treatment of the Pusan Janglim wastewater plants. SABR has obtained high SS removal efficiency which also showed flexible to load change. SABR has gained avg. organic removal rate 12.2gSCOD/㎡·d (1.4㎏TCOD/㎥·d) in stage 1+2. Nitrification was mainly accomplished at stage 1, 2 in that nitrification rate was avg. 2.6gNH₄-N/ ㎡·d (0.2㎏NH₄-N/㎥·d). This system also sustained high VSS conc. 14,111㎎VSS/l (about 177gVSS/㎡·d) in stage 1, as a results, substrate(ogranics, ammonia)removal was completed in stage 1, 2. There was also observed that nitrification rate was influenced by pH change. Those results suggest that SABR combined sand filter applicable in small-scale treatment plants without secondary clarifier.

김창수 Chang Soo Kim

DOI: Vol.14(No.1) 65-69, 1998

Removal effect of fluoride and iron in raw water by water treatment chemicals was investigated. Raw water contained fluoride was taken from the Juduk water treatment plant in Chungbuk and distilled water which iron was added in was used. Removal effect of fluoride by activated alumina was good in order of acid, neutral and basic activated alumina reagent. But the commercial alumina which is being used in water treatment was 50% of activated alumina. Ion exchange resin was 15% of activated alumina. Iron in raw water was removed perfectly by the 0.5㎎/ℓ chlorine dioxide(ClO₂) and stabilized chlorine dioxide(S-ClO₂). But removal rate was 98% and 78% expectively in the 0.1㎎/ℓ ClO₂ and S-ClO₂, and 89% by ClO₂, 76% by S-ClO₂ in the 0.05㎎/ℓ.

권순영 , 유성환 , 우영국 Soon Young Kwon , Sung Whan Yo , Young Gug Woo

DOI: Vol.14(No.1) 71-77, 1998

The combined process of biofilm and suspended growth type for denitrification was used to treat seafood processing wastewater containing high organic and nitrogen compounds. The reactors were made by transparent prexiglass and consisted of the two sequent anoxic and oxic basins for nitrification and denitrification. Wastewater for experiment was supplied from collecting reservoir at industrial wastewater treatment plant twice a week. Concentration of wastewater was ranged in the TCOD of 4,000∼5,500㎎/l, TSS of 3,000∼5,000㎎/l, TKN of 500∼600㎎/l, T-P of 197∼275㎎/l and Temperature of 14℃∼29℃. In order to get stable efficiency, the experiment was operated for 180 days. During experiment the efficiency was shown stably in treating organic and nitrogen compounds. The results were as follows: 1) Most of organic materials were removed at the first anoxic reactor, but nitrogen compounds were removed at the second oxic reactor. 2) The efficiency for organic and nitrogen treatment were 93% and 86%, respectively at the organic volumetric loading rate of 0.75KgTCOD/㎥·d and nitrogen volumetric loading rate of 0.1KgTKN/㎥·d. 3) At predenitrification process, the nitrogen was removed above 90% at the loading rate of 0.3∼1.2KgN/㎥· d, but removed in the range of 20∼60% at 0.15∼0.6KgN/㎥·d at the post-denitrification process. 4) The removal efficiency in the organic volumetric loading rate of 0.75KgTCOD/㎥·d was higher than that of 0.50KgTCOD/㎥·d on the temperature of 26℃∼29℃. Consequently, the denitrification process of this study will get the satisfied effluent below the effluent limit of BOD 30㎎/l if the reactor be designed at the loading rate of 0.6KgBOD/㎥·d and HRT=3days without addition of extra-Carbon source.

이현동 , 정원식 , 지재성 Hyun Dong Lee , Won Sik Chung , Chai Sung Gee

DOI: Vol.14(No.1) 79-86, 1998

Water quality in water distribution system is changed biological, physicochemical and organoleptic qualities, and then it has been more worse. Chlorine residual was used to as indicator for prediction of water quality behavior, characteristics and ensurement of regulatory requirment. Therefore, M&O of chlorine residual is to be important for water quality management in water distribution system. This study was performed to study the relationship for water quality changes and characteristic of chlorine residual decay according to pipe type and diameter, hydraulic effect, and water quality parameter. Results of this study indicated decay coefficient of chlorine residual was to characterized with pipe type and diameter. Also it was to different hydraulic effect and initial chlorine residual concentration and water quality parameter as temperature, TOC, etc.

김용환 , 조재현 , 이용우 , 정용대 , 이원권 Yong Hwan Kim , Jae Hyun Cho , Yong Woo Lee , Yong Dae Jeong , Won Kwon Lee

DOI: Vol.14(No.1) 87-97, 1998

Treatment of industrial wastewater containing high concentration of ammonia was studied using biofilm media such as Bio-CAP^(TM), Bio-PO.P^(TM) and Ringlace. Among the various configurations of biofilm media process, Bio-CAP^(TM)-Bio-POP^(TM) media process was considered as the best process for organic removal and nitrification reaction. Volumetric organic removal and nitrification rate of this process approached to approximately 6㎏ COD/㎥/day and 800g NH₃,-N/㎥/day, respectively. Settler was located between Bio-CAP^(TM) and Bio-POP^(TM) reactor to remove the inhibitory effect of SS on nitrification in 2nd Bio-POP^(TM) reactor. Organic removal rate and nitrification rate of Bio-CAP^(TM)-Bio-POP^(TM) process were 5 and 4 times higher, respectively than those of general activated sludge process. By using Bio-CAP^(TM)-Bio-POP^(TM) media process, it was expected to decrease the required area for treatment of industrial wastewater containing high concentration of organics and ammonia.

박금숙 , 김인호 , 김명호 , 김영희 , 이정전 Piao Jin Shu , In S . Kim , Myung Ho Kim , Young Hee Kim , Jung Jun Lee

DOI: Vol.14(No.1) 99-103, 1998

In this research, new coagulant was synthesized by copolymer reaction using starch and acrylamide. The compositions of testing materials were SCSA30(starch 30%, acrylamide 70%), SCSA40(starch 40%, acrylamide 60%) and SCSA60(starch 60%, acrylamide 40%). Then, coagulation tests under proper pH condition were conducted for sample obtained from a mixing control tank of nightsoil treatment plant in Na-ju City. Concentrations of coagulant prepared for the tests were w_t. 2%, w_t. 4% and w_t. 6%. Optimum dosages were determined sludge. 1. It is concluded that pH 7.0 was optimum condition for the test using w_t. 2% of SCSA30. 2. The best coagulation reaction in terms of suspended solid concentration showing 32㎎/L was obtained when w_t. 4% of SCSA30 was used. 3. In terms of effluent concentrations for the BOD_5, COD_(Cr), TKN and water content w-1. 4% of SCSA30 consistently showed the highest removal efficiency. However, w_t. 2% of SCSA40 was shown to be the best for the treatment of Total Phosphorus. 4. For the test of dehydration ability, the lowest value of specific resistance was obtained where w_t. 4% of SCSA30 was applied. Optimun dosage was turned out to be 50㎖ of coagulant per 1ℓ of sample.

학회자료

DOI: Vol.14(No.1) 105-108, 1998