The purpose of the system is the neutralization of acids and alkali discharges from demineralization plants that are made to flow into a storage tank where, in the middle of the pump, are mixed together. Via a pH-meter, which detects the pH value thus obtained, it has the consent, to means metering pump, to inject neutralizing the product. reached the neutralization, the pH-meter from the consent to the emptying of the tank and to the release into sewer with the same recirculation pump