Amok Ltd. is the operator of uranium mining and milling facilities at Cluff Lake in northwestern Saskatchewan. All contaminated liquid effluents from these facilities have been subject to treatment by chemical and physical methods before release to the environment. In particular, a secondary treatment system (STS) has been operated adjacent to the tailings management area to reduce the concentration of radium-226 to below the maximum levels allowable in the final effluent. The STS has operated for over 2 years at a nominal rate of 4000 m3/day. During this time, the most stringent regulatory limit on radium-226 concentration (0.37 Bq/L = 10 ×10−12 g/L total, based on a monthly arithmetic mean) has been exceeded on only two occasions. The process regularly removes 99% of the radium from the effluent stream. Data is presented on chemical addition rates, efficiencies of system components, and the significance of each stage of the treatment process. In addition, several modifications have been made to the STS. Recently, a primary treatment system has been added to the effluent treatment process. Preliminary indications are that this system has increased the overall efficiency of the system.