The algal blooms in stagnant streams and lakes have caused many problems. Excessive algae leads to disturbance of ecosystem and overload of water treatment processes. Therefore, phosphorus(P), source of algal blooms, should be controlled. In this study, a filtration trench has been developed to convert dissolved phosphorus into hydroxyapatite(HAP) so that it could be crystallized on the surface of ‘phosphorus removal granular material’; and residual particulate phosphorus could be removed by additional precipitation and filtration. The front and rear parts of filtration trench consisted of ‘phosphorus removal granular material contact bed’ and ‘limestone filtration bed’, respectively. As a result of the column test using phosphorus removal granular material and limestone serially, PO4-P was removed more than 90% when EBCT(empty bed contact time) of the contact bed was over 20 minutes; and T-P represented 60% of removal efficiency when total EBCT was over 1.5 hours. The results of column tests to figure out the sedimentation characteristics showed that more than 90% of particulate phosphorus could be removed within 24 hours. It was necessary to optimize the filtration part in order to increase removal efficiency of T-P additionally. Also, it was confirmed through the simulation of Visual MINTEQ that most of particulate phosphorus in the column tests is the form of HAP. Based on the results of the study, it could be suggested that the design parameters are over 0.5 hour of EBCT for phosphorus removal granular material contact bed and over 1.5 hours of EBCT for limestone filtration bed.

One of the major sources causing eutrophication and algal blooms of lakes or streams is phosphorus which comes from point and nonpoint pollution sources. HAP (hydroxyapatite) crystallization using granular alkaline materials can achieve the decrease of phosphorus load from wastewater treatment plants and nonpoint pollution control facilities. In order to induce HAP crystal formation, continuous supply of calcium and hydroxyl ions is required. In this research, considering HAP crystallization, several types of lime-based granular alkaline materials were prepared, and the elution characteristics of calcium and hydroxyl ions of each were analyzed. Also, column tests were performed to verify phosphorus removal efficiencies of granular alkaline materials. Material_1 (gypsum+cement mixed material) achieved the highest pH values in the column tests consistently, also, Material_2 (gypsum+slag mixed material) and Material_3 (calcined limestone material) achieved over pH 9.0 for 240 hours (10 days) and proved the efficiencies of long-term ion supplier for HAP crystallization. In the column tests using Material_3, considerable pH increase and phosphorus removal were carried out according to each linear velocity and filtration depth. T-P removal efficiencies were 87.0, 84.0, 68.0% and those of PO4-P 100.0, 97.0, 80.0% for linear velocity of 1.0, 2.5, 5.0 m/hr respectively. Based on the column test results, the applicability of phosphorus removal processes for small-scale wastewater treatment plants and nonpoint pollution control facilities was found out.

본 연구는 전선공장 에나멜와이어 코팅과정에서 발생하는 악취의 저감방안을 마련하고, 악취를 저감한 사례를 소개하는 목적으로 수행하였다. 조사방법은 악취 발생원과 오염물 질의 이동경로를 확인하고, 복합악취와 지정악취물질을 측정하였다. 또한, 악취저감시설 인 촉매산화장치의 효율에 관한 실험을 실시하고, 전선공장의 악취 문제점을 제시하였다. 조사 결과, 공정상에서 관리 부주의로 인하여 악취를 저감 시켜주는 촉매산화장치의 촉 매가 높은 온도에서 제 역할을 수행하지 못했고, 발생된 오염물질이 옥상의 Push-Pull 덕 트 및 다양한 이동경로를 통하여 외부로 악취가 확산되는 것으로 나타났다. 이와 같이 측정된 자료를 토대로 사업장 실정에 알맞은 개선안을 마련하였고, 실제로 사업장 관리 를 개선한 결과 악취가 50 % 정도 저감된 것을 확인 할 수 있었다.

This study was conducted to investigate purchasing behavior of jeans consumers and to find differences in jeans evaluative criteria according to consumers' characteristics. Male and female university students participated in the study. Quota sampling method was used to collect the data. Data from 492 questionnaires were used for the statistical analysis. Descriptive analysis, factor analysis, Cronbach's alpha coefficient, ANOVA, Duncan test, and t-test were conducted. Three factors of jeans evaluative criteria classified (i.e., external criteria, internal/aesthetic criteria, internal/quality criteria). Results indicated that most of respondents put on jeans wear more than three times per a week and 38.1% of respondents reported that they owned three to four jeans products on average. Department store was the most used place to buy jeans product with 44.2%. 27.5% of respondents spent from 50,000 won to 100,000 won on purchasing jeans. Style was the highest important jeans evaluative criterion with 36.2%, followed by fitness, price, color, condition of washing treatment. Women respondents considered aesthetic criteria and quality criteria more importantly than men did. Respondents who were on a high income and spent more than 200,000 won per a month on apparel more concerned aesthetic criteria and external criteria than the other respondents did. Results of this study provide a basis for understanding jeans consumers' purchase behavior and evaluative criteria.