The CDI (Capacitive deionization) is one of the desalination technologies that use a carbon material electrode with large surface area and excellent electrical conductivity. Recently, research on a MCDI (Membrane Capacitive deionization) process, which is a combination of an ion-exchange membrane, has been actively conducted. In this study, we tried to find out the water quality of treated water and the concentration characteristics of concentrated water through TDS analysis by MCDI conventional and circulation process. In producing treated water, there was no significant difference in adsorption efficiency between MCDI conventional and circulation process. It was confirmed that both processes adsobed more than 96 %. However, the MCDI conventional process showed a low yield of 50 %, whereas the MCDI circulation process showed a high yield of 97.6 %. It's because, the wasted water was reused at desorption. In the case of the TDS concentration using MCDI circulation process, as the cycle progressed, the TDS concentration was concentrated up to 1,300 mg/L, but the rate gradually decreased. It is believed that this is because the volume of the concentrated water tank is limited, and the amount of soluble ions gradually decreases. As a result of analyzing the wasted water at MCDI circulation process through Ion Chromatography, it was confirmed that the concentration of all ions were concentrated. However, there was no significant difference in the types and proportions of analyzed ions. It is judged that the types and concentration of ions do not have a significant effect on adsorption and desorption in the MCDI circulation process.

This paper presented experimental results for circulation type UV-TiO₂ photocatalytic oxidation process. We have developed UV-TiO₂ photocatalytic oxidation process with activated carbon to control odor and VOCs in indoor and industrial applications. In this study, common indoor air pollutants, namely ammonia, formaldehyde, hydrogen disulfide, toluene were selected to investigate their efficiencies for UV-TiO₂ photocatalytic oxidation. In high concentration test, the decomposition efficiency was high in order as ammonia, toluene, formaldehyde, hydrogen disulfide. Three type of individual processes are tested for ability to increase decomposition efficiency. UV-TiO₂ photocatalytic oxidation combined process with activated carbon was excellent among the three type processes without reference to gas species. It was considered that this circulation type process will overcome short retention time for treatment for UV-TiO₂ photocatalytic oxidation. It will promise that this circulation type UV-TiO₂ photocatalytic oxidation combined process can apply indoor and industrial applications to remove odor and VOCs quickly.

The aim of our research was to apply experimental design methodology in the optimization of N, N-Dimethyl- 4-nitrosoaniline (RNO, which is indictor of OH radical formation) degradation using gas mixing-circulation plasma process. The reaction was mathematically described as a function of four independent variables [voltage (X1), gas flow rate (X2), liquid flow rate (X3) and time (X4)] being modeled by the use of the central composite design (CCD). RNO removal efficiency was evaluated using a second-order polynomial multiple regression model. Analysis of variance (ANOVA) showed a high coefficient of determination (R2) value of 0.9111, thus ensuring a satisfactory adjustment of the second-order polynomial multiple regression model with the experimental data. The application of response surface methodology (RSM) yielded the following regression equation, which is an empirical relationship between the RNO removal efficiency and independent variables in a coded unit: RNO removal efficiency (%) = 77.71 + 10.04X1 + 10.72X2 + 1.78X3 + 17.66X4 + 5.91X1X2 + 3.64X2X3 - 8.72X2X4 - 7.80X1 2 - 6.49X2 2 – 5.67X4 2. Maximum RNO removal efficiency was predicted and experimentally validated. The optimum voltage, air flow rate, liquid flow rate and time were obtained for the highest desirability at 117.99 V, 4.88 L/min, 6.27 L/min and 24.65 min, respectively. Under optimal value of process parameters, high removal(> 97 %) was obtained for RNO.

For the purpose of evaluating the eco-efficiency(EE) on surplus heat generated from industrial process, techniques of life cycle assessment are adopted in this study. Because it can be indicated both environmental impacts and economic benefits, EE is well known as a useful tool for symbiosis network on the sustainable development of new projects and businesses. To evaluate environmental impacts, the categories were divided into two areas of resource depletion and global warming potential. It can be seen that environmental impact increased a little but much higher economic benefit on the company, environmental performance and economic value were improved on the apartment by the district heating, respectively. In result, eco-industrial park(EIP) project on surplus heat should be found sustainable new business because the EE was in the area of fully positively eco-efficiency and, moreover resource depletion was taken place than the reduction of greenhouse gas.