Objectives: The main purpose of this study was to identify problems such as cooking fumes and lack of ventilation in school cafeterias and evaluate the improvement in the reduction of indoor pollutants in the cooking rooms through renovation. Methods: Three schools were selected for renovation and the spatial structures and air conditioning system of the cafeterias and cooking rooms wre investigated after renovation. The air conditioning systems were improved by the renovation work according to the characteristics of each school, and the concentration of indoor pollutants was measured and evaluated through CFD analysis. Results: The concentration of indoor pollutants in the cafeterias and cafe rooms was decreased after renovation. Conclusion: Air conditioning systems in the schools cafeterias and cooking rooms were improved in order to solve the problems of ventilation, and the indoor air quality improvement rate ranged from a minimum of 11% to a maximum of 40%. The renovation of cafeterias and cooking rooms was conducted to optimize the ventilation systems and this contributed to indoor air quality improvement by preventing the inflow of pollutants.

As awareness about the danger of radon in indoor air has increased, various studies have been conducted to reduce the source of radon. This study was performed to investigate the effect of radon mitigation technology in a railway tunnel. Radon barrier paint and radon shield membrane developed to reduce the concentration of radon in soil and construction material were applied in the tunnel. The tunnel was divided into three sections, A, B, and C, and radon barrier paint, a buffer section, and radon shield membrane were applied, respectively. After securing a sealing screen to the floor and division of each section, radon concentrations were measured and compared before and after each product was applied, and statistical significance was confirmed through the Wilcoxon signed rank test. Measurement was performed with the In-Situ Method and Closed Chamber Method. Radon concentration measured by the in-situ method changed in A section to 124.1 Bq/m2/day from 614.1 Bq/m2/day (79.8%, z=-2.521, p<0.05), in B section to 416.2 Bq/m2/day from 467.1 Bq/m2/day (10.9%, z=-0.980, p=0.327), and in C section to 47.3 Bq/m2/day from 645.6 Bq/m2/day (92.7%, z=-2.521, p<0.05). Radon concentration measured by the closed chamber method recorded a decrease in A section to 88.8 Bq/m3 from 364.2 Bq/m3 (75.6%, z=-2.201, p<0.05), in B section to 471.8 Bq/m3 from 583.3 Bq/m3 (19.1%, z=-0.700, p=0.484), and in C section to 115.9 Bq/m3 from 718.8 Bq/m3 (83.9%, z=-2.521, p<0.05). In addition to soil, it is very important to mitigate radon from building materials with a high contribution rate of radon in order to manage radon by source. Due to the spatial characteristics of railway tunnels, soil and wall concrete structures are exposed as they are, so it is considered that radon mitigation actions are required utilizing verified methods with high mitigation efficiency.

This study were performed to control color and satisfy discharge permission standard of effluents operating a small dyeing factory based on a fiber. The color removal efficiency was very high when the injection site of Sodium Hypochlorite(NaOCl) was more discharge site of second sedimentation tank than of first sedimentation tank. Although NaOCl usages was reduced from 1.0 ㎥/day to 0.8 ㎥/day, the removal efficiency of BOD, COD and SS were similar. At the time, the optimal Hydraulic Retention Time(HRT) was calculated to twenty five minute after NaOCl injection until effluent discharged finally. After controlling NaOCl usages and HRT, the effluent quality of BOD, COD, SS, Color and Chloroform were 8.6 mg/L, 24.7 mg/L, 43.3 mg/L, 191.2 degree and 0.346 mg/L, respectively, so that was satisfied to discharge permission standard.

Most small laundry factory has been operated without not only environmental expertise but also technical process. The objective of this study is to get the optimal coagulation dosage for satisfaction of discharge permission standard of laundry wastewater treatment plant(WTP) effluents by jar test.The coagulants are alum and sodium hydroxide(NaOH), coagulants aids is polymer. Also, the best coagulation reaction was shown in the following conditions ; Alum 4.13g/L, NaOH 1.03g/L, Polymer 0.27g/L on average. The optimal coagulation dosage could be reduced costs to 4.43 million won a year. It was considered that operating a small WTP was an important technical data in same industry.