A liquid chlorine supply canister is connected by a supply tube and venturi chamber to a recirculating pipe that discharges into a storage-mixing tank into which sewage effluent is received from a source. The supply tube is provided with a filter/orifice assembly. A pump causes circulation of sewage effluent through the venturi chamber and develops a suction in the supply tube which draws chlorine through the filter/orifice assembly and into the flowing sewage effluent stream. A recirculation pipe from the venturi chamber into the tank, causes turbulence of sewage effluent and dissolved chlorine (either solution or gaseous) within the tank for efficient mixing of the chlorine component with the constituents of the sewage effluent. A crossover tubing is connected with the pump discharge pipe and the recirculation pipe and enhances the induction of chlorine (disinfected) effluent into an effluent discharge pipe leading to a spray field.