Laboratory experiments were conducted to investigate the effect of digestion temperature on the settleability and dewaterability of anaerobically digested sludge. The digesters were operated at a hydraulic retention time of 20 days with a loading rate of 0.63~0.66kg volatile solids per cubic meter per day at the temperature of $35^{\circ}C$ and $55^{\circ}C$. A mixed primary and secondary municipal sludge was used as a feed. The interface height of the sludge during settling test was recorded to identify settleability. As a measure of dewaterability of the sludge, specific resistance and capillary suction time were also measured with and without chemical conditioning. Higher digestion efficiency was obtained at $55^{\circ}C$ than $35^{\circ}C$. However, the settleability and dewaterability of the sludge at $35^{\circ}C$ were quite higher than those of the sludge digested at $55^{\circ}C$. The optimum dosages of ferric chloride for sludge conditioning were 0.4% and 0.6% at $35^{\circ}C$ and $55^{\circ}C$, respectively. The filtrate COD of the sludge digested at $55^{\circ}C$ was higher than at $35^{\circ}C$, which means that poor dewaterability of the sludge result in high filtrate COD.

이용객의 이용압력에 의한 토양 및 식생에 대한 영향을 알아보고자 부산시의 어린이대공원과 금강공원의 이용 통제구역과 이용지역내에 20개의 조사구를 설치하고 본 조사를 실시하였다. 토양경도는 이용지역에서 평균90kg/ cm2 이상을 보여 식물생장에 지장을 주었고 이용객통제에 따른 토양경도의 완화효과가 있었으나 다른 토양특성들은 그 효과가 나타나지 않았다. 식물군집분석결과 이용압력에 의해 특히 관목층식생의 피해가 매우 컸으며 종다양성을 떨어뜨리게 하는 결과를 보였다. 그러나 단기간(2년)의 이용객통제는 식생의 자연복원과 종다양성 증진에 좋은 작용을 하고 있었다.

최근 작물의 공장적 재배는 『식물공장』이라는 단어로 대표되는, 새로운 재배방식의 하나로서 세계적으로 주목받고 있다. 식물공장(plant factory or factory- style plant production system)이라는 단어의 의미와 같이 『시설내의 작물을 공장제품의 생산과 동일하게 재배하는 시스템』이다. 즉 자연환경에 의존하지 않고 인공환경하에서 식물을 공장적으로 재배하는 방식을 의미한다. 이를 위해서는 지하부의 양액, 지상부의 온습도, 탄산가스, 광 등에 대한 고도의 환경제어 및 작업의 자동화가 필요하다.(중략)

Emission of hazardous and volatile organic chemicals from solid waste landfill site was become to important issue because of environmental pollution and health risk by such chemicals. Laboratory batch and continuous experiments were conducted respectively to elucidate isothermal sorption behaviors and transport phenomena(by gas through unsaturated solid waste layer) in wet solid waste-gas system. Source separated and size reduced refuse(bulky waste) and incinerated ash were used after controlling water content, and trichloroethylene(TCE) was chosen among many such chemicals because of it's generality among those man-created pollutants. Isothermal TCE sorption equilibria wet solid waste-gas system can be described in linear equation and partition coefficient in this system can be estimated approximately by the simple equation derived from schematic structure of the system. Transport equation modified by instantaneous equilibrium sorption fraction and kinetic sorption rate(overall mass transfer capacity coefficient) simulated well the column experiment results.

These studies were conducted to: a) investigate work patterns and productivity indices, b) rate performance levels of employees and c) determine the suggested levels of personnel and labor hours for the effective labor control in school foodservice. Eighteen elementary school foodservices in Seoul were selected in order to analyze work patterns by the work sampling methodology. Allowance time and performance rating by VTR observation was done to determine the standardized labor hours. The results were as follows. The average percentage of each work function of the total work functions such as direct work function, indirect work function and delay were 65.57%, 8.12%, 26.31% respectively. The productivity index is 0.92 min/meal. The average working and delay hours per week of the foodservice director, foodservice employees and supply person were 33.64 hours, 23.25 hours, 38.52 hours respectively. The percentage of delay hours of total labor hours for foodservice employees and supply person were 42.27% and 24.0%. The standardized work hours and the appropriate levels of foodservice employees of 17 elementary school foodservices were examined: The average rating of the foodservice employees work was 1.19 and British Insulated Calendarer Cables (BICC) allowance rate was 19.40% on the average. The total work hours of foodservice employees were 172.64 hours per week and levels of personnel were 4.53 persons. BICC allowance rate was applied: The standardized work hours per week was 180.95 hours and appropriate levels of personnel were 4.11 persons based on legal 44 working hours.

Denitrification activity of microbial communities in sand-gravel sediments and biofilms developing on a concrete riverbed of an urban small stream, Nogawa River, was measured monthly by laboratory incubations after the acetylene inhibition technique during une year from December 1987. The annual mean denitrification rate of the biofilm samples, 1.5 mgN m-2 h-1. was higtrer than the rate ut the sandgravel sediment samples. 0.8 mgN m-2 h-1. Contrary, ratios of the denitrified nitrogen to the total inorganic nitrogen fluxes was lower at the stretch where an attached microbial community developed un the concrete riverbed the stretch with sand-gravel riverbed. The longer residence times of water masses ut the site with a sand-gravel riverbed is responsible for the above relationship. Based on the average denitrifieation rates, if all the channel of Nogawa River were covered with concrete, the proportion of denitrified nitrogen to the input nitrogen should decrease to 1.3 %, whereas the ratio is 2.5% when the riverbed is composed of sands and gravel. The results suggest that the efficiency of nitrogen removal by benthic denitrification is strongly affected by the structure of a channel of the river.

The purpose of this study was to investigate the value evaluation of foodstuff of 448 college students residing in the urban area. As a result of analyzing the value of each foodstuff, two to four factors were drawn from each foodstuff. The factors were classified into the social-conceptual factor, the preparatory factor, the quality factor, the economic factor, the subjective factor, and the complex factor. It was learned that the social-conceptual factor was dominant over the majority of college students in the evaluation of value of foodstuffs. There was a difference in the factor of the value evaluation for each foodstuff according to sex and the main growth region among the college students. A significant difference was found between the sexes regarding the preparatory factor and the economic factor. Also, in accordance with the main growth region, there was great difference in the social-conceptual factor(except for the Korean rice cake).

미국 캘리포니아주 Orange County에 위치한 Water Factory 21(WF-21)은 생물학적 처리공정을 거친 도시하수를 재생하여, 이 재생수를 지하수지층으로 유입되는 해수의 침투를 막기 위한 Reinjection System에 이용하고 있다. 장치 구성 공정은 Lime처리, Air Stripping, 사여과, 활성탄처리, 역삼투막 및 염소처리 등으로 이루어지며, 이에 대한 각 처리공정의 효율성에 대하여 실험을 실시하였다. 3년간의 장기간에 걸친 실험결과로부터, 도시하수에 대한 RO Membrane 처리수는 음료 수질 기준에 적합한 고수질의 물을 생성할 수 있음을 입증했다. Pilot Plant 실험에선 Lime Clarifier만으로 전처리를 실시하여 성공적인 결과를 얻었으며, 또한 저압 (250 psi)이 적용된 새로운 Membrane을 사용하여 에너지 절약을 통한 비용 절감 효과에 대한 실험도 상당한 가능성을 보여주었다.

Water samples were collected every one hour during July 23-24 1987 from the Minami-Asakawa River and sewage effluents into it. Mearldaily loading and budgets of some bioelements, such as carbon, nitrongen and phosphorrs, were estimated. the fluxeds of suspended matter, organic carbons and ammoioum appeared to remove by self-purification pocesses. On the other hand, those of nitrate, nitrite and chlorophyll a, which were considered to be produced in situ, increased with the river flow. From these results, it was suggested that the river is not only the place for transportation of bioelements but also that for their metabolism.

본(本) 연구(硏究)는 대구시(大邱市)의 주요 하천(河川)인 이천(梨川), 범어천(汎魚川), 칠성천(七星川), 신천(新川), 달서천(達西川) 및 공단천(工團川)의 오염상태(汚染狀態)를 조사(調査)하여 도시하수(都市下水)의 효과적(效果的)인 처리(處理)와 금호강(琴湖江)의 오염방지책(汚染防止策) 수립에 필요한 기초자료(基礎資料)를 제공(提供)코자 하였다. 시기별(時期別) 각(各) 하천(河川)의 pH, DO, COD, 질산염 및 인산염을 분석(分析)한 결과(結果)는 다음과 같았다. 1) 각(各) 지점별(地點別) 평균치(平均値)는 pH 7.3~8.2, DO 흔적~6.5ppm, COD 20.4~116.9ppm, T-N 23.2~31.7ppm, -N 18.3~27.7ppm, -N 0.08~1.89ppm, -N 0.19~1.51ppm, -P 2.50~17.28ppm이었다. 2) 지점별(地點別) 오염도(汚染度)가 가장 높은 곳은 공단천(工團川)이었으며 12개월(個月)동안의 평균치(平均値)는 pH 8.2, DO 흔적, COD 116.9ppm, T-N 23.2ppm, -N 18.3ppm, -N 1.89ppm, -N 1.51ppm, -P 17.28ppm이었다. 3) 시기별(時期別)로 비교(比較)하면 pH, DO, COD, T-N, -N의 함량(含量)과 pH는 겨울철이 여름철보다 높았으며 -N and -P의 함량(含量)은 여름철이 다소 높았다.

It is aimed to survey the housewive's interest and understanding on the Korean traditional dishes in relation to the importance and the significance of those dishes in the Korean traditional folk ceremony. Questionnaires were distributed to and answered by 667 housewives ranging from the the mother of kindergarden children to the mother of seniors in the university. Some of the significant findings and speculations derived from the analysis of data are summarized as follows: 1. About 90% of subjects have taken the knowledge on cooking the traditional dishes from their mothers and their grandmothers. And they have had many opportunities to known about traditional dishes through the home life education. 2. The kinds of the Korean traditional dishes which are used often at the folk ceremony are Tto k(Korean rice cake), Shikhae (fermented rice fruits punch), Sujong Kwa (persimmon fruits punch), Whachae(flower, fruits punch) etc. 3. About two thirds of the subjects have a little knowledge about Korean traditional special menu for the Korean folk ceremony, however, most of them observe New York's Day, Chusuk (The Korean Tranks giving Day), Dongji (The winter solstice), and Deborum (The 15th of the January on lunar Calender). 4. About 74% of the subjects use Korean traditional foods when they have Korean traditional folk ceremony. But there is a tendency to use nontraditional dishes among young housewives. 5. More than 73% of the housewives agree to the idea that Korean traditional dishes have to be succeeded and developed. 6. Most of the housewives think the Korean traditional folk ceremony is important and they are willing to make Korean traditional foods on the occasions, but they also think the ceremony must be rather simplified.

The results obtained by survey on 599 respondents of different age groups for preference of 84 prepared foods were subjected to statistical principal component analysis, factor analysis, analysis of variance, scheffe verification, and discriminant analysis so as to find a structure of preference for foods. The results may be summarized as follows: 1. The results of the factor analysis indicate that 84 prepared food items may be classified into 3 groups and that by knowing an indvidual's preference to one prepared food, one can presume his preference to the others in the same group without carrying out actual test. 2. The results from an analysis of variance showed that most of primary school children extremely liked snacks, seniors liked Korean cooking, primary school children and collegians had weaknesses for western cookings while kindergarden children and adults over 50 years old disliked them.