Abstract: A method for continuously neutralizing quantities of acidic and alkaline waste materials is disclosed. Acidic and alkaline quantities are successively passed through the same weak ion exchanger. The passage of each of the quantities effectively neutralizes that quantity in the ion exchanger while, at the same time, effectively regenerates the exchanger for use in neutralizing the next successive quantity of waste material passed therethrough. Relatively highly acidic and highly alkaline waste materials are first neutralized in a holding vessel before being passed into the ion exchanger.