최의소 , 임봉수 Eui So Choi , Bong Su Lim

DOI: Vol.3(No.2) 2001-2006, 1987

This study was conducted to characterize the microbial growths on media in aerobic and anaerobic fixed-film processes upon the variation of organic loading rates. It appears that the growth on media became more likely to be suspended rather than attached as organic loading rate reached around 3 ㎏ COD/㎥/d. At an organic loading rate less than around l㎏ COD/㎥ /d the microbial attachment became stronger in aerobic than in anaerobic condition. As the organic loading rate increased, the effluent quality became poorer. However, at the same loading rate, the effluent concentration varied little, even influent concentration greatly increased. The maximum F/Mv (㎏ COD)/㎏ MLVS/d)ratio measured from anaerobic condition was about 1 which is lower than that of activated sludge process. The computed minimum SRTs were respectively 7.6 days for anaerobic and l.ldays for aerobic condition.

정용 , 정재춘 , 권숙표 , 이수환 Yong Chung , Jae Chun Chung , Sook Pyo Kwon , Soo Hwan Lee

DOI: Vol.3(No.2) 2007-2021, 1987

The Hanging Biological Contactor(HBC), which has been developed in 1984 and currently in experimental stage in Korea and Japan is a very new fixed-film process utilizing attached microorganisms on the polyvinylydene-chloride fiber media. It is similar to rotating biological contactor process but the media immersed in the wastewater does not rotate and appropriate air is supplied by the aeration apparatus underneath. Thes study was to identify HBC microorganisms and to determine their relative abundance. One pilot scale and two full scale Hanging Biological Contactors(HBC) were investigated for various microorganisms. Microorganisms found were pretty much similar to those fixedfilm reactors such as rotating biological contactors and trickling filters. In the start-up study of pilot scale HBC plant, Beggiatoa became highly populated in the first stage and the species diversity index increased along the stages with the time lapse. When the aeration level increased, the populations of Beggiatoa and Paramecium decreased, while those of Vorticella, Linonotus, Diplogaster(nematode), Philodina(Rotifer), and annelid Worms increased. Microorganisms also differ abundance by stages. More populations of Beggiatoa, Peranema, Amoeba, Paramecium, Trachelocerca, Aspidrsca, Linonotus, Oxytricha, Vorticella, Opercularia, Carchesium, Tokophrya, Philodina, and annelid Worms in the first 2 stages occured, while Arcella, Difflugia, Stylonychia, Trachelophyllum and Epistylis were shown higher abundance in the last stage (stage 3 and 4).

김환기 , 권문선 Hwan Gi Kim , Moon Sun Kwon

DOI: Vol.3(No.2) 2022-2036, 1987

The substrate utilized in this study is a synthetic wastewater similar to septic tank effluents containing a considerable amount of nitrogenous compounds. The processes for the removal of nitrogen consist of nitrification and denitrification. The carbon source needed in denitrification and the oxygen and the alkalinity required in nitrification are important in the process for the removal of nitrogen. In order to reduce the treatment cost, a three-stage Biological Fluidized Bed reactor as an Anoxic-Aerobic-Anaerobic process was conceived. The efficiency and the rationality for the removal of nitrogen in wastewater using this reactor are discussed. The results obtained by varing the recycle ratio, the hydraulic retention time and the recirculation ratio between reactors showed that the organic removal efficiency and the nitrification efficiency were more than 90% and 92%, respectively, and the denitrification efficiency was above 95% when C/N ratio was above 2.75. In these cases, the recycle ratio, the total hydraulic retention time and the recirculation ratio were found 30, 3hrs and 2 respectively, and the internal recycling in denitrification stage was needed only to fluidize the media well. The following experimental equation could be derived from distinguishing between the oxygen required for nitrification and the oxygen required for organic BOD oxidation. [grO₂/day] Total=1.5 [grBOD-5/day] + 4.95 [grNr/day] The relationship between the alkalinity and the recirculation ratio in nitrification, the feasibility of phosphorus removal using the principle of releasing phosphorus in the anaerobic reactor were also discussed briefly.

옥삼복 , 김원만 Sam Bok Ok , Won Man Kim

DOI: Vol.3(No.2) 2037-2043, 1987

This study researched into the denitrification which occurs at the reactor, when the wastewater flow in upflow method in the reactor filled up with floating media in anaerobic state. Making the proportion of 3/1, charged the detention time into 2.47, 3.53, 4.63, 7.69, 8.90 and 16.5hr when the detention time was over 4.63hr, the removal efficiency of NO₃-N was over 98 %. When the detention time fixed in 4.63hr, and charged the proportion of C/N into 3/1, 3/2 and 3/3, the removal efficiency of NO₃- N was 98.1%, 95.1 % and 87.2 %. So in the experimental limit of this research the most desirable was the case that the proportion of C/N was 3/1 and detention time 4.63hr. This study had the highest value mainly at the first step by the measurement of the microbial quantity in reactor, that was closely connected with the rapid occurring denitrification at the first step.

김교붕 , 박성배 , 정용 , 권숙표 Gyeo Bung Kim , Sung Bae Park , Yong Chung , Sook Pyo Kwon

DOI: Vol.3(No.2) 2044-2052, 1987

This study was performed to investigate the possibility of THM formation by chlorination in the Han river and tributary waters in Seoul area form March to May 1987. Raw water samples were collected at 6 points in the Han river, 4 points in the tributary waters, and were chlorinated at 20℃ with sodium hypochlorite solution in laboratory and THM concentrations were measured after 24 hrs. THM of the finished water in water treatment plants along the Han rever was also determined by head spacegas chromatographic method. The results were as follows: 1. THMs of the finished water in water treatment plants were detected in the range 7.5∼14.1 ppb. 2. A range of 2.5∼7.6% of the bromide in raw water was converted to bromine-containing THM by chlorination in water treatment plants. 3. The higher the raw water polluted in the Han river, the higher THMs were produced by chlorination. The raw water of the Han River in the vicinity of Seoul could produce 35∼72 ppb of THMs by high level of chlorinatron and the tributary waters could produce them in the range of 104∼126 ppb. 4. The brominated THM formation by chlorination was definitely dependent on bromide concentration in water. 11.7±5.6% of the bromide in raw water could be converted to THMs by high lerel of chlorination. From the above results, the possibity of THM formation would necessitate more extensive control for safety water supplies.

엄경숙 , 송민영 , 정재춘 , 정용 Kung Suk Eum , Min Young Song , Jae Chun Chung , Yong Chung

DOI: Vol.3(No.2) 2053-2062, 1987

The acute toxicity and bioconcentration of heavymetals, Hg(HgCL₂), Pb(Pb(NO₃)₂), Cd(CdCl₂) and Cr(CrO₃) on a freshwater fish, Apiochilus latipes were investigated in a laboratory. The results were as follows: 1. The 24hr-LC_(50) values were 0.345㎎/ℓ for Hg, 3.4㎎/ℓ for Pb, 0.317㎎/ℓ for Cd and 3.8㎎/ℓ for Cr. 2. The combined effect of heavy metals was also investigated for Hg(031 $quot;/. )+pb(3.2㎎/ℓ )and Cd(0.3 ㎎/ℓ )+Cr(3.8㎎/ℓ ). No synergistic and antagonistic accumulation of those metals occured in the fish body for 24 hour exposure times. 3. When Apiochilus latipes was exposed to 1/5 and 1/10 of 24hr-LC_(50) concentrations of Hg(0.0690㎎/ℓ, 0.0345㎎/ℓ ), Pb(0.68㎎/ℓ, 0.34㎎/ℓ ), Cd(0.064㎎/ℓ, 0.032㎎/ℓ ) and Cr(0.75㎎/ℓ, 0.38㎎/ℓ ), their BCF(Bioconcentration factor) obtained were 117.90 and 49.30 for Hg 71.41 and 23.29 for Pb, 20.62 and 25.93 for Cd and 10.63 for Cr. The highest BCF appeared in Hg 4. Based upon the exposure time and concentration the following linearity between logarithum of BCF and logarithum of pollutant concentration(P)Xexposure time(T) was obtained: Hg; log BCF=1.63 log P.T+2.35(r²=0.688) Pb; log BCF=0.967 log P.T+1.12(r²=0.889) Cd;log BCF=0.681 log P.T+1.62(r²=0.805) Cr; log BCF=0.984 log P.T+0.33(r²=0.726) Where, P: Pollutant concontration (㎎/ℓ ) T: Exposure time (day)

박찬영 , 정수현 Chan Young Park , Soo Hyun Chung

DOI: Vol.3(No.2) 2063-2068, 1987

Poly acrilic acid was employed to flocculate water soluble protein from fish processing effluent. The froth formed by microfine aeration contained most of the soluble protein. BOD of the waste water was decreased apparently after the treatment. From the experiment, the optimal conditions for the recovery of protein are as follows: pH of waste water: 5∼6 molecular weight of flocculant : 30,000∼70,000 concentration of flocculant : 200∼300 ppm temperature of waste water: 25∼300℃

신정식 , 박성배 , 정용 , 권숙표 Jung Sik Shin , Sung Bae Park , Yong Chung , Sook Pyo Kwon

DOI: Vol.3(No.2) 2069-2078, 1987

This study was performed to investigate the distribution of enterobacteria resistant to heavy metal compounds (Pb(II), Zn(II), Co(II), Te(II), Cr(VI), Cd(II), Hg(II))in the stream water and sediment receiving municipal and industrial wastewater. The results were as follows: 1. Similar numbers of total count, coliforms and fecal califorms were present in stream waters receiving either industrial or municipal wastewater. However, the higher numbers of those bacteria were present in the stream sediment receiving industrial wastewater. The concentrations of Pb(II), Zn(II), Cr(VI), Cd(II) and Hg(II) were higher in the stream sediment receiving industrial than municipal wastewater. 2. The higher number of heavy metal-resistant bacteria were present in the stream water receiving industrial wastewater. The percentage of enteric strain isolates survived in＞10^(-3)M concentrations of Pb(II) and Zn(II) was over 97% Among the enteric strains isolated from the stream receiving municipal wastewater, 25.3% of the river water isolates and 32.9% of the sediment isolates were survived in＞10^3M concenration of Co(II). The percentage of enteric strain survived in＞10^(-3)M concentrations of Cr(VI) was 1.0% and 2.9% for the river water and sediment isolates from the stream receiving municipal wastewater, and 7.8% and 11.7%, for those from the stream receiving industrial wastewater. Among the enteric strain isolates from the rever water and sediment, none was survived in＞10^3M concentrations of Cd(II) and Hg(II). Only 2 strains (1.1%) of the sediment isolates from the stream receiving industrial wastewater was survived. Generally the enteric strain isolates showed the highest resistance to Zn(II) and then Pb(II), Co(II), Te(II), Cr(VI), Cd(II) and Hg(II) in decreasing order. 3. Bacteria isolated from the river water and sediment were streaked on Muller Hinton agar containing 10^(-3)M concenrations of 7 heavy metal compounds with various combinations. Among the enteric strains isolated from the stream receiving municipal wastewater, 47.9% of the sediment isolates were survived in the media containing more than 2 heavy metal compounds. While, the survival ratio was 81.0% and 85.0% from those in the stream receiving industrial wastewater.