In this study, the cooling performance change according to the arrangement of the fin-tube heat exchanger using a single tube and the cooling performance change according to the air flow rate were studied. The arrangement of basic heat exchanger was set to 4 columns and 4 rows, and the performance change was studied while changing the columns and rows. In addition, the performance change was investigated by changing the air flow rate of the basic heat exchanger.

Electrochemical reductive extraction of tin from semiconductor plating process wastewater was experimented using synthetic wastewater. Copper and graphite plate were used as a cathode and an anode, respectively. The tin extraction could be optimized in pH 0.5 and polar space of 60 mm. The extraction rate of tin per minute was increased as current and initial tin concentration increased, and more than 87% and 97% of tin could be extracted within 80 minutes at 500 mg/L and 1,000 mg/L of initial tin concentration, respectively. The electrochemical reaction orders and kinetic coefficients were 1.24 ~ 1.26 and 0.004 ~ 0.006 (L/mg)(n − 1)min−1. The residual concentration of tin could be expressed as Ct= (Co −0.246+ 0.0012t)−4.065.

Food waste, food leachate and livestock wastes from an usual farm and a farm using much disinfectant were mixed to incubate within anaerobic serum bottle for BMP test. The methane yield rate and lag phase were determined by the modified Gompertz model and the Logistic model. The maximum methane yield rates by the modified Gompertz model were 15.9 ~ 41.0 mL CH4/g VS and higher than by the Logistic model. The modified Gompertz model was more appropriate than the Logistic model to have higher determination coefficient R2. The methane fermentation of mix with sole livestock waste from the farm using much disinfectant had ninefold lag phase and 40% or lower maximum yield rate comparing with the mix with sole usual livestock waste. The methane yield rate from a tonne of mix was increased as the ratio of food waste and food leachate increased. The cumulative methane yield was in the proportion of 40 m3 to a tonne of food wastes. The results of BMP test were analyzed by a response surface methodology (RSM) and modelized to a binomial expression, which was verified by analysis of variance (ANOVA) and to be appropriate for this case.

Economic and environmental aspects of electrochemical copper recovery from LCD manufacturing process and through hole plating process for PCB circuit board wastewater were evaluated. The extraction rate of copper per unit energy was decreased as HRT increased and initial copper concentration decreased. About 65 minutes was determined as the optimal HRTs which could maximize the productivity of copper recovery on energy. The extracted mass of copper from the wastewater were 0.045 g at 50 mg Cu/L, 0.083 g at 1,000 mg Cu/L and 0.098 g at 3,000 mg Cu/L by unit energy (Wh) for 60 minutes, respectively. LCA (Life Cycle Assessment) technique determined the electrochemical recovery of copper to have more effect on global warming than other environmental impact categories.

Electrochemical reductive extraction of copper from LCD manufacturing process and through hole plating process for PCB circuit board wastewater was experimented using synthetic wastewater. Copper plate which could be used as raw material through melting with extracted copper from wastewater and graphite plate were used as a cathode and an anode, respectively. The copper extraction could be optimized in pH 2 and polar space of 45mm. The extraction rate of copper per unit energy was decreased as HRT increased and initial copper concentration decreased. As the optimal HRTs which could maximize the productivity for copper on energy, 80 ~ 110 min at 50 mg/L, 64 min at 1,000 mg/L and 77 ~ 98 min at 3,000 mg/L were determined, respectively.

The extent of heavy metal pollution in agricultural soils near the abandoned mine land site was investigated using their concentrations from the 47 sampling sites in B mine. Samples were prepared using 0.1N HCl -Korean Standard Methods- and then analysed for Cd, Cu, Pb, As and Cr by Inductively Coupled Plasma Spectrometer. In addition, soil and mine tailing samples were sequentially extracted to investigate the chemical speciation of heavy metals in them. The soils in the vicinity of mining area are highly contaminated by heavy metals ranging up to 5.96㎎ Cd/㎏, 253.3㎎ Cu/㎏, 76.7㎎ Pb/㎏, and 15.45㎎ As/㎏, according to the analysis of Korean Standard Methods. The heavy metal levels by the sequential extraction are much higher than its level by Korean Standard Methods, and little correlated with each other. Based on the results, it is suggested that the As pollution in agricultural soils near the AMLS should be dealt as of prior significance in establishing reclamation strategies for the area.