In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of 600 o C were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of 300 o C would be the most economic conditions.

Iron and steel scrap have been reused to produce new steel and cast iron in the steelmaking and foundry industry for more than 150 years, but the accumulation of tramp elements contained in steel scrap such as copper, tin, antimony, and arsenic is a major concern. This is primarily because these tramp elements are difficult to remove in conventional steelmaking processes. In particular, the presence of copper during the recycling of steel scrap can cause severe surface cracking during hot rolling (hot shortness), inhibit recrystallization during hot forming, and reduce ductility in deep drawing. For these reasons, considerable efforts have been made in recent decades to develop a technology that can remove copper from ferrous scraps[1-3].

The objective of this study is to improve water quality resulting from rainwater purification treatment and to utilize reclaimed water purification system and high-class treatment purification system. This can be done by developing a purification treatment technique through resolution of discharged ozone problems by circulation-type of ozone treatment method with the use of a high-efficiency air-cooled cylindrical ozone generator. While the final removal rate of BOD showed the highest rate of 96% for 12g without showing a great difference for the ozone injection amount of 9g and 12g, the final removal rate of COD upon treating for 12 minutes showed 73%, 66%, 93% and 96% for 3g, 6g, 9g and 12g, respectively, exhibiting similar treatment results to that of BOD. The removal of TSS and VSS due to ozone treatment was indicated not to have occurred. Also, upon passage of the magnetized water device, the removal rate of colon bacterium and general bacteria was shown to be about 35%, while a high removal rate exceeding 70% was indicated during the initial 3 minutes. Upon final treatment for 12 minutes, sterilization power above 99% was exhibited. Upon treatment using the magnetized water device and the OH- radical generator, not only dissolved suspended materials but also excellent sterilization power appeared to be identifiable.

A purpose of the present study is to derive optimum study factors for removal of heavy metals using combined alternating current electric/magnetic field and electric membranes for the area contaminated with heavy metals in soil or underground water. ORP (Oxidation Reduction Potential) analysis was conducted to determine an intensity of tendency for oxidation or reduction of the samples contaminated with heavy metals, and electrical membrane treatment was used with adjustment of concentrations and voltages of liquid electrode (Na2SO4) to derive a high removal rate. Removal constants were analyzed to be 0.0417, 0.119, 0.1594 when the voltages were 5V, 10V, 15V, respectively, and treatment efficiency was shown to increase as the liquid electrode concentration was increased. Keywords: heavy metals, electric/magnetic field, ORP, electrical membrane

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