A filtration system may be required in conjunction with an ozone system for home water treatment. This system removes destroyed microorganisms and the matter to maintain stability and yield optimum water clarity. Like chlorine, ozone kills microorganisms by oxidation. With ozone, the ozone itself attacks the microbe. Bacteria kill rates are vastly different between ozone and chlorine because the method of kill is different.
Ozone ruptures bacteria's cellular membranes, so reactivation of the cell is impossible.
It may be said to act blindly because no limits to disaffection have been found in the numbers or species eliminated. Chlorine treats water much slower because it must first diffuse through the cell wall of the bacterium. Thus, contact times for chlorine eliminating a microbe can be 2.5 to 55 times longer than with ozone. In fact, tests show ozone 3,125 times faster an oxidant than chlorine. This means that while contact time is important when sizing an ozone system to treat a particular water source, the most important variable is the quantity of ozone transferred into the water.