김동윤 , 이상봉 , 황덕흥 Dong Youn Kim , Sang Bong Lee , Dug Heung Hwang

DOI: Vol.8(No.2) 59-66, 1992

Many lakes and rivers have reached levels of eutrophication that make them unacceptable for recreational activities and as municipal and industrial water supply sources. The eutrophic state is a direct result of an increase in the availability of both organic and inorganic nutrients. This increase in the nutrient concentration may be caused by wastewater discharges and urban or agricultural stormwater runoff. But in some waters, there must not be neglected as appreciable internal nutrient sources in the form of benthal deposits. And so the objective of this experiment is to understand the characteristics of phosphorous release from sediment as an internal pollution source and perform pertinent water management. As the phosphorus released from sediment was influenced seriously by anaerobic state, the protective measures of eutrophication must be setted up against not only external sources but also internal ones together.

강성현 , 오재룡 , 김형선 , 양동범 Sung Hyn Kahng , Jae Ryoung Oh , Hyung Seon Kim , Dong Beom Yang

DOI: Vol.8(No.2) 67-75, 1992

The effectiveness of domestic and foreign dispersants was compared by Labofina and swirling flask tests. Six domestic dispersants were shown to be less effective in oil dispersion than foreign products. By Labofina test, they dispersed 6-34% of the test oil at dispersant-to-oil ratio of 0.1, while dispersed 2-22% by swirling flask test. The effectiveness of dispersants varied with the type of crude oil and decreased with increasing viscosity of oil. Dispersion linearly increased in proportion to the dispersant-to-oil ratio. It was found that the $quot;self-mix$quot; dispersant, Enersperse 700, was the most effective in dispersing various crude oils. Toxicity tests with brine shrimp Artemia were performed on 12 dispersants. Two domestic dispersants had 48-hr LC_(50)`s ranging from 5.6 to 6.6 ppm which were similar to hydrocarbon slovent-type dispersants, while three dispersant concentrates had 48-hr LC_(50)`s ranging from 24.0 to 26.2ppm.

송준상 , 이재안 , 송민영 , 권명희 , 이인선 Jun Sang Song , Jea An Lee , Min Yong Song , Myeong Hee Kwon , In Seon Lee

DOI: Vol.8(No.2) 76-83, 1992

In order to isolate and identify Acinetobacter calcoaceticus, which can uptake the phosphorus luxuriously, from 27 samples 63 Gram negative strains were isolated first. And then, 17 strains were selected which had the biochemical characteristics of catalase positive and oxidase negative secondly. According to morphological and biochemical results, 5 strains were identified to Acinetobacter calcoaceticus bio lwoffi. The 5 strains, which had phosphorus uptake activities, didn`t grow at anaerobic state, but grew well at aerobic state, according to the results of optical density at 600㎚. PO₄-P concentration in the batch culture media were incresed about 40% during the incubation of anaerobic state, and then decreased suddenly because of phosphorus luxury uptake during the incubation of aerobic state. And 2 strains, such as P-1 and P-4 showed about 90% phosphorus uptake characteristics. The Total Organic Carbon(TOC) concentration in the batch culture media were not changed during the incubation of anaerobic state, this results showed that the strains can not obtain the energy from organic carbon at anaerobic pure culture state, but TOC concentration of their media decreased suddenly at aerobic pure culture state, because of using the organic carbon for their energy source. And 2 strains, such as P-3 and P-4 showed about 80% TOC removal characteristics after 48 incubation hours.

김원만 , 옥삼복 Won Man Kim , Sam Bok Ok

DOI: Vol.8(No.2) 84-92, 1992

This study was carried out to select the most economical altitude of distribution reservoir to minimize electric cost that is the major portion of costs for the maintenance of water supply service system. The water distribution patterns by the altitude in Seoul have been classified into three types. As required pressure and area(required eletric power ratio) (y) by the water tap distribution altitude is the function of economical distribution reservoir altitude (x), the equations are summarized as follows; 1. Majority of the water taps are located in lower altitude : case I y=0.010x² -0.600x+102.000 Economical distribution reservoir altitude(45.0m) 2. Maiority of the water taps are located in higher altitude : case II y=0.013x²-1.500x+164.000 Economical distribution reservoir altitude(72.7m) 3. Water taps are evenly located in both lower and higher altitued: case III y=0.010x²-0.902x+129.030 Economical distribution reservoir altitude(61.0m)

이보영 , 정용 Bo Young Lee , Yong Jung

DOI: Vol.8(No.2) 93-99, 1992

This study was conducted to measure residual aluminum concentrations, affected by the flocculation process in water treatment, the raw and tap water of 14 major cities in Korea during January and February 1989. The results are summarized as follows ; 1. The Maximum aluminum concentration detected in the raw water was 0.171㎎/ℓ in samples collected in the Inchon region. 2. The Average aluminum concentration detected in the tap water of 14 cities 0.149㎎/ℓ. 3. The samples were categories by aluminum concentration in the tap water and the results indicated that aluminum concentrations between 0.1∼0.2㎎/ℓ showed the highest frequency of 53.5%. 4. Of the overall samples, 22.4% exceeded the WHO`s recommended guideline value of 0.2㎎/ℓ. The samples of the Chunchon region showed the lowest value whereas the frequency of concentration exceeding the WHO`s value was 50.0% in the Pusan region. 5. Among the three kinds of coagulation in the water treatment system treated with alum, without coagulants and with mixed coagulants, the average aluminum concentration of the distribution system treated with alum showed the highest value. 6. The aluminum concentration in January and February was 2.58㎎/ℓ fold higher compared to that of May in Seoul region.

이찬기 , 윤주환 , 권재혁 Chan Ki Lee , Zu Whan Yun , Jae Hyouk Kwon

DOI: Vol.8(No.2) 100-108, 1992

Trickling filter was seldom considered for the piggery wastewater treatment since high suspended solids(SS) and biochemical oxygen demand(BOD) contents could hamper its operation due to the frequent clogging problem. In order to minimize the clogging problem, a pretreatment process using the rice straw column filtration was applied in this study. The filtered effluent was then applied to a two-stage laboratory trickling filter unit which used a crushed stone medium, and the removal of organics and conversion of nitrogenous compounds in the wastewater were observed. The operational results of laboratory trickling filter system showed that piggery wastewater was successfully treated without clogging problems. The trickling filter with effluent recycle improved the effluent quality probably due to the dilution effect. In addition treatment by two stage trickling fitter process could not achieve the full nitirification potential, probably due to the high ammonia-nitrogen concentration. It was also noticed that BOD test were affected by nitrification, especially at low organic concentration.

최의소 , 권수열 Eui So Choi , Soo Youl Kwon

DOI: Vol.8(No.2) 109-115, 1992

This study was conducted to compare biological treatment processes for uneasily biodegradable dyeing wastes with trickling filter(TF), activated sludge(AS) and their combination processes; TF/AS, AS/TF, TF/SC(solid contact) and RF(roughing filter)/AS. In addition, the effects of developed and specific bacterial strains applied to activated sludge were also compared. The COD removal efficiency of trickling filter was better than that of activated sludge. It appeared that total COD applied to trickling filter was removed about 35% by biooxidation, 10% by air stripping and chemical oxidation, and 20% by adsorption and settling. In comparison to individual process, the COD removal efficiencies of combination processes were not greatly increased. While the constructed Pseudomonas putida was failed to acclimate to dyeing wastes, mixed strains with specific strains slightly enhanced the treatment capability. The treatment capability of A stage in A/B process showed little improvement but the improvement seemed to be greatly affected by DO and temperature of A stage.

홍사욱 , 정규혁 Sa Uk Hong , Kyu Hyuck Chung

DOI: Vol.8(No.2) 116-124, 1992

The distribution and fate of anionic surfactants in Jungrang stream and in down stream of Han river tributary and in Jinwi stream of Ansung stream tributary were examined. The concentrations of linear alkylbenzene sulfonates(LAS) in river were determined by gas-liquid chromatogaphy. The ratio of concentrations of LAS to those of methylene blue active substances(MBAS) were estimated to 27-31% in Jungrang stream and 27-65% in Jinwi stream and 35-58% in down stream of Han river tributary. However, levels of LAS and its contribution to the MBAS in rivers was found to vary with the nature of the sampling location, i. e. depending whether it was above, below or in the vicinity of a sewage effluent discharge. The concents of LAS and carbon number of alkyl chain were high in Jungrang stream and low in Han river. In its seasonal variations, it is high in November and low in August.

유을열 Eul Leal Ryu

DOI: Vol.8(No.2) 125-134, 1992

In this paper, attempts were made to analyze the effects of the construction of public sewerage systems on the water quality in public water areas and to evaluate the treatment efficiency with the inflow of industrial sewage in Japanese large cities. The findings of this study were as follows; 1. The water quality in the public water areas has gradually improved as with the increase in the treated-sewage ratio. 2. The treatment-efficiency has not decreased though the industrial sewage flow into sewage treatment plants. 3. The attainment rate of environmental standard does not improve proportional to the increase in the treated-sewage ratio of public sewerage systems since the 1980s. An increase in the amount of pollution load from the residential wastewater, prevents from increasing the attainment rate of environmental standard in the public water areas. This finding implies a need of designing the anti-pollution policies focused on the domestic sewage.