김응호E . H . Kim

DOI: Vol.18(No.1) 1-7, 2002

N/A

최근주Keun Joo Choi,김상구Sang Goo Kim,손희종Hee Jong Son,류동춘Dong Choon Ryu,류재익Jae Ick Ryoo,손인식In Sik Son

DOI: Vol.18(No.1) 9-17, 2002

Japan Environmental Agency announced 14 kinds of endocrine disruptors was detected on 130 watersheds of Japan in 1998 and the Ministry of Environment of Korea announced 13 kinds of endocrine disruptors involving Bisphenol-A was detected in domestic watersheds in 2000. According to the report, bisphenol-A, nonyiphenol and 4-n-heptylphenol were detected in all domestic watersheds. This study was carried out for finding removal method of 13 species of endocrine disruptors on water treatment processes. The concentrations of prepared endocrine disruptors standard water were about 10 ㎎/L and we analyzed the concentration of endocrine disruptors by W Absorbance. All 13 pieces of endocrine disruptors could be absorbed into the powder activated carbon(PAC) and the phthalates(DBP, DEP, DEHP) could be coagulated but other endocrine disruptors could not be coagulated by coagulant. Ozonation showed that it could not remove endocrine disruptors by measuring W Absorbance, but other researchers reported ozonation could transfered endocrine disruptors to isomer.

이상화Sang Wha Lee,이기세Ki Say Lee,곽종운Jong Woon Kwak

DOI: Vol.18(No.1) 19-26, 2002

Fe-Al dual salts were prepared by blending poly aluminium silicate chloride, Hi-PAX, and polyferric sulfate, PFS. Both AI-based (Hi-PAX, Fe/Al=0) and Fe-Al based (Fe/Al=0.1) coagulants were used to investigate the removal efficiency of turbidity, SS, and COD from dyeing effluents. At 40℃, Fe-Al coagulant maintained high removal efficiency of turbidity and SS at pH7∼9, whereas Hi-PAX exhibited a maximum coagulation efficacy at pH6∼7 followed by a rapid decrease of coagulation efficacy over pH7. Therefore, Fe-Al coagulant is expected to be effective for the treatment of basic wastewater possibly due to enhanced sedimentation contributed by Fe(III) and improved coagulability contributed by Al(III). Fe-Al coagulant was also characterized by the analysis of zeta-potential, size distribution, and FTIR spectrum. Hi-PAX exhibited a distinct decrease of zeta-potential with rising pH, while Fe-Al exhibited a gradual decrease of zeta-potential with rising pH. From the size distribution of coagulating species, Fe-Al was confirmed to have average size groups of 20∼50 ㎚ and 80∼200 ㎚, respectively. FTIR spectrum indicated some possible interaction between AI and Fe components in the blended salts.

성낙창Nak Chang Sung,강동효Dong Hyo Kang,박경철Kyung Choul Park

DOI: Vol.18(No.1) 27-34, 2002

Sewage sludge and livestock wastewater with food waste were mixed and digested. The results are as follows. In case of mixing digested sewage sludge with food waste, the pH vaule was lowed by the organic acid of a large quantity at the beginning of the inspection so that NaOH was poured into reactor. But in case of mixing digested livestock wastewater with food waste, during experimental the pH value was set neutral because of high alkalinity of livestock wastewater. In the case of VS removal ratio the result showed the higher removal value about 5.3% in R2(1:1), R₃(1:2) mixing sewage sludge and food waste than sewage sludge digestion alone, and reactor R-5 in which livestock wastewater and food waste were mixed with rate of 1:1 showed the highest removal value about 6.3% than livestock wastewater digestion alone. Though food waste with initial CI^- concentration of 3,000㎎/L showed about 4,700㎎/L at the highest point in the reactor R₃(1:2), there had no effect on VS removal and the production of CH₄. In the case of sewage sludge digestion alone and livestock wastewater digestion alone, the production rates of CH₄ gas per gVS removal were 125mL and 51mL. In the production rates of CH₄ gas per gVS removal, reactor R₂ and R₃ in which sewage sludge and food waste were conbined with mixing ratio of 1:1, 1:2 showed 68mL and 71mL which were more than sewage sludge digestion alone. But R-5 and R-6 in which livestock wastewater and food waste were conbined with mixing ratio of 1:1, 1:2 showed 18mL and 8mL. Therefore, it is concluded that sewage sludge and livestock wastewater mixing with food waste is more possible than sewage sludge and livestock wastewater digestion alone.

정현미Hyen Mi Chung,강태구Tae Gu Kang,염철민Cheol Min Yeom,이덕길Duk Kil Rhee,윤제용Je Yong Yoon

DOI: Vol.18(No.1) 35-45, 2002

This study was performed to select indicator microorganism practically applicable to water treatment plants for evaluating the removal of microorganisms such as viruses and protozoan cysts. Total of seven microorganisms were investigated. Four microorganisms for representing bacteria (E. coli, fecal coliform (FC), total coliform (TC) and heterotrophic plate counts (HPC)), two for protozoan (aerobic spore formers (ASF) and Clostridium perfringens (CP) spore) and one for viruses (F-specific RNA coliphage) were examined as a possible indicating microorganism. Each candidate microorganism was measured every month for 20 months in source and treated water of three water treatment plants (WTPs) characterized with varying water quality (lake or river; high or low BOD). The distribution of microorganisms in source and treated water were measured, and log removals of microorganisms in each water treatment plant were compared. Major findings are that ASF and HPC appeared to be the best indicator microorganism for evaluating pathogenic removal in water treatment plant although ASF was considered better. This decision was made from the following three criteria i) not only high but also stable level in the source water enough for quantitative evaluation, ii) the feasibility of detection method, iii) stability of the organisms in the water environment. For HPC and CP, the growth of microorganism and no detection in treated water were indicated as a weak point, respectively in this consideration.

Joong Dae Choi , Jae E Yang

DOI: Vol.18(No.1) 47-55, 2002

Two small agricultural watersheds were monitored from March 1998 to December 1999 to measure runoff and the pollutant loads of selected NPS(Non-point Sources). Runoff was measured and water quality was analyzed every two weeks for SS, T-N, T-P and COD. Annual runoff coefficients ranged from 0.47 to 0.75 depending on rainfall amount and intensity. SS concentrations maintained most of the time the 1st grade water quality standard of 25 ㎎/L or less while T-N concentrations could not meet the lowest reservoir water quality (5th grade) standard of 1.5 ㎎/L all the time. It was analyzed that the constituents of T-N were mainly supplied from groundwater. T-P and COD concentrations were in between the first and the lowest water quality criteria. The importance of T-N control by means of nutrient management and rural wastewater treatment was emphasized. About 80 to 95% of the NPS pollutants were discharged during a short flooding period of 2 to 3 months. NPS pollutant load per unit area varied depending on daily rainfall. Patterns of pollutant discharges from the watersheds were different between rainy and normal seasons. It was recommended that the use of pollutant load per unit area must be applied very carefully, and the control strategies of NPS pollutants for rainy and normal seasons must be separately developed.

김성홍Seong Hong Kim,최영균Young Gyun Choi,정태학Tai Hak Chung

DOI: Vol.18(No.1) 57-66, 2002

Batch digestion experiments were carried out to investigate the effect of digestion type and temperature on solids reduction and nitrogen release and transformation. Solids reduction kinetics can be well expressed by exponential decay equation with 2 parameters for aerobic or intermittent aerobic digestion and aerobic digestion is the fastest among 3 types. As the digestion temperature increases, decay constant is increased by 1.044 of temperature sensitivity coefficient. Oxygen deficit is very effective method to kill and dissolve aerobic organism, but this does not mean that solids reduction rate is higher in anaerobic digestion than aerobic or intermittent aerobic digestion. Organic nitrogen released from organisms is accumulated as ammonia nitrogen in anaerobic digestion. But released nitrogen is accumulated as nitrate nitrogen in aerobic digestion until the available alkalinity is exhausted. Nitrification is partially possible after the available alkalinity is exhausted because alkalinity is produced by the hydrolysis of biomass. Nitrogen removal is the highest in the intermittent aerobic digestion and the efficiency is up to 57% for 34 days.

김종민Jong Min Kim,허성남Seong Nam Heo,노혜란Hye Ran Noh,양희정Hee Jeong Yang,임연택Yeon Taek Lim,정완종Wan Jong Jeong

DOI: Vol.18(No.1) 67-76, 2002

The long-term data (`88∼2000), which have been released by National Institute of Environmental Research (NIER) and Ministry of Construction and Transportation on the water quality and hydrological characteristics in Lake Paldang, were analyzed to find their monthly and annual variation tendency. Water volume tended to decrease during summer season, this phenomenon was assumed that dam authority might open the floodgate in advance to prevent an inundation. And DO saturation ratio exceeded 95% during ail seasons. That time, the concentration of chlorophyll-a (about 10㎎/㎥or higher) and T-P (about 0.03 ㎎/l or higher) denoted high level. Correlation between conductivity and COD denoted middle level (r=0.597, r²=0.36, p$lt;0.01). Conductivity denoted the minimum value in January and February, that was the coldest and freezing season in Lake Paldang. COD denoted the maximum value in June, whereas the inflow and pollutant load were high in July and August. Therefore It was assumed that the effect of dilution was stronger than that of pollutant load. T-N annual variation pattern of annual mean level was similar to COD pattern, but T-P denoted an opposite pattern to T-N. N:P mass ratio seemed to be more affected by T-P concentration than T-N. Annual mean level of N:P mass ratio tended to increased during 1991-2000. In June, transparency denoted the highest level and the concentration of chlorophyll-a & suspended solids denoted the lowest level. The relationship between transparency and suspended solids were relatively high (r=-0.6, r²=0.362, p$lt;0.01) than the relationship between transparency and chlorophyll-a (r=-0.269, r²=0.072, p$lt;0.01).

윤제용Je Yong Yonn,변석종Seok Jong Byun,염철민Cheol Min Yeom,조순행Soon Haing Cho,김충환Chung Hwan Kim,채선하Seon Ha Chae

DOI: Vol.18(No.1) 77-86, 2002

Chloramine is one of the disinfectants and it is produced from the reaction between ammonia and chlorine. It has long been used to curb microorganisms and disinfection byproducts from drinking water. In this study, we investigated the characteristics of Trihalomethanes (THMs), Haloacetic acids (HAAS) and Total Organic Halides (TOX) (which means a surrogate of chlorinated byproducts) as chloramine process was applied in S pilot plant near downstream of Keum river and also compared with the results of bench scale experiments. Major findings were that chloramination process reduced up to 74% of THMs, 79% of HAAS and 73% of TOX when compared with those of the breakpoint chlorination practice in pilot plant experiments. In bench experiments, the percentage of reduction increased up to approximately 90% of THMs and HAAs, and 80% of TOX. In all experimented cases, HAAs was more highly detected than those of THMs. And the least formation of HAAS was found at the Cl₂/NH₃-N ratio of 4 as a mass basis. From these results, chloramine was feasible as a secondary disinfectant in S pilot plant.

정명훈Myung Hoon Chung,박명주Myung Joo Park,정용찬Yong Chan Chung

DOI: Vol.18(No.1) 87-94, 2002

Electrolytic hydrolysis of toxic chemicals such as pesticide and nerve agent simulants was examined in the presence of catalysts that range from amino acids to functionalized surfactant and inorganic solids (zeolite, silica, and titanium dioxide). Hydroxide ions produced from cathode activate the catalysts by deprotonation of the active group, and proton ions around anode can not only neutralize hydroxide ions but make aqueous solution around anode strongly acidic enough to kill microorganisms. The cleavage rates of toxic chemicals have improved with the aid of catalysts: among the catalysts tested, functionalized surfactant shows exceptionally high cleavage rate against PNPDPP, and slight increase in cleavage rate was observed with the inorganic solid like zeolite. Cysteine was the most effective among amino acids for the deactivation of organophosphates. The sewage water from the Suwon area was also tested to result in the remarkable reduction, especially with titanium dioxide, in COD, decolorization, deodorization, and turbidity. The applicability of the electrolytic hydrolysis system for the deactivation of toxic chemicals in aqueous system and its modification needed are thoroughly studied in this paper.

김지훈Ji Hoon Kim,최혁Hyeok Choi,김관엽Kwan Yeop Kim,김형수Hyung Soo Kim,김진모Jin Mo Kim

DOI: Vol.18(No.1) 95-101, 2002

This study was focused on investigating ability to maintain long-term high flux, especially variation of flux according to concentration ratio in actual reservoir water purification system using membrane separation technology. The pilot plant was operated in dead-end-filtration mode. The membranes used were hollow fiber microfilter with nominal pore size 0.1㎛. The permeate flux was maintained 25LMH(ℓ/㎡ hr). Materials causing SS and turbidity were almost completely removed and removal percent of UV_(260) and DOC was 40%. Measured max. concentration of SS and turbidity about concentrated water during any one cycle corresponded with predicted max. concentration through simple mass balance, and each measured max. concentration of UV_(260) and DOC was 84%, 80% of predicted max. concentration.