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Magnetic field effect on CaCO 3 precipitation is the key parameter in evaluating the effectiveness of Anti-scale Magnetic Treatment (AMT). The purpose of this study was to investigate magnetic fields influence on CaCO 3 precipitation in high and low super-saturated CaCO 3 solution by varied pH CaCO 3 solution using circulation flow fluid system. The observation results in the high super saturated solution (pH 8.5) showed the increase of precipited CaCO 3 in magnetized solutions compared to those in non-magnetic solution during circulation process. In the low super-saturated CaCO 3 solution (pH 6.4) it was found that magnetic treatment increased CaCO 3 precipitation after circulation process. In high super-saturated solution, magnetic field strengthens ion interactions, which reduce precipitation during circulation process. However, in low super-saturated CaCO 3 solution, magnetic field weakens hydrate ion interaction which indicated by decreasing of the conductivity of solution. It increases the precipitation of CaCO 3 after the circulation of magnetization process has completed.

A cooling tower is a unit that helps the process of heat dissipation. Thus, thermal effectiveness is a vital variable for cooling tower performance. Scale precipitation can obstruct thermal effectiveness of the heat exchange unit due to its natural high thermal resistance properties. The ozonation process is expected to decrease the potential of scale precipitation thereby improving cooling tower thermal performance. Cooling water is circulated from the tower before ozone and UV rays are applied. This study aims to determine the characteristics of the effects of ozonation on the overall thermal fouling resistance of forced draft type-counter flow-closed system cooling towers and the quality of water circulation by using the Practical Ozone Scaling Index and Langelier Saturation Index methods. Water quality from closed system cooling towers is determined by conducting laboratory tests. The results obtained from this study indicate that when ozone is present the overall thermal tower resistance of the closed system cooling towers is reduced by 7 x10-6 m2K/W. Ozone can also improve the water quality of closed system cooling towers.