Abstract
Disappearance of free available chlorine in water during storage in the FRP (fiber reinforced plastics) tank was investigated. It was considered that the disappearance of free available chlorine in the water consists of the following factors. 1) the vaporization of free available chlorine from the water surface 2) the chlorine consumption caused by unknown components in water supply 3) the chlorine consumption caused by FRP 4) the disappearance of free available chlorine by certain reactions with sunbeams passing through the tank The third and the fourth factors could be negligible compared with the other factors. The following equation was derived in order to account for the disappearance of free available chlorine in water during storage in the FRP tank. dCF/dt=-αCF-KeS (1/V) where, CF is the concentration of free available chlorine in the tank water. α is the apparent rate constant for the chlorine consumption by components in water supply. Ke is the apparent rate coefficient for vaporization. S is the air-water interfacial area. V is the volume of water. This equation may be applied for the disappearance of free available chlorine in the tank water, when the water was continuously pumped from the tank at a constant flow rate.
