Abstract
Chlorination is the most common method used for disinfection of drinking water. However, growing concerns about the potential hazards of disinfection by-products have emerged many efforts to develop alternative disinfection methods. In this study, a new disinfection method was developed using low-dose chlorine in combination with a high level of water-dissolved gas as a chlorine reduction disinfection technique. This research investigated the potential of using pressurized air for the disinfection. It also studied whether the technique using pressurized air could reduce the quantity of chlorine required. First, water containing microbes was chlorinated, which resulted in changes to the physiological features of the microbe cell membranes, and enabling gas to easily penetrate the cell membranes under high pressure. After that, sudden depressurization while the gas inside the cells forming a large amount of bubbles, resulting in the rupture of the microbe and cell death. Pre-chlorination followed by pressurized-air disinfection at 0.6 MPa improved microbial control and was able to reduce by up to 90% the dose of chlorine compared to normal chlorination. The improved disinfection effect was observed after a chlorination period of 10 min before gas treatment. As a result, successful disinfection using a non-greenhouse gas in combination with reduced chlorine treatment may help address recently emerging problems in water disinfection.
