[en] The waste treatment facility at Mound Laboratory was recently modified for the treatment of plutonium-bearing wastes. Prior to July 1, 1975, the facility had been run at pH 8.8; however, since the plant was modified it has been run at pH 11.3 with different chemical dosages. The improvement in effluent quality using the higher pH process (pH 11.3) has been dramatic. Prior to the changeover, the system effluent activity levels ranged from 2-3 dis/min/ml (9-14 x 10^-4 μCi/l) specific ²³⁸Pu; after the changeover effluent activity levels ranged from 0.3--0.5 dis/min/ml (1.4--2.3 x 10^-4 μCi/l) specific ²³⁸Pu. Total activity discharged (on a monthly basis) has been cut by more than a factor of 2, because of the changeover to the high pH process. Effluent levels are about as low as can be obtained in this type of waste treatment process