Abstract: A batch liquid purifier using a reservoir, an ozone generator, and a pumping system is arranged for contacting the liquid with an ozone containing gas so that it is purified either during a direct outflow to a purified liquid chamber or during a circulational flow back to the reservoir. The flow circuit can include a liquid gas separator and venting of gas to atmosphere via an ozone concentration reducer. Pumping, valving, and controls can be accomplished in a variety of ways.