Two computer programs were developed for the design of ammonia stripping towers: (1) a design program for counter current twoers and (2) a design for cross-flow towers. The programs determine the dimensions of the tower required for given operating conditions, evaluate investment and operating costs of the process, and provide information on pH requirements, and the exit temperature on the waste water so that freezing conditions can be predicted. Particle, splash, and film packings can be evaluated for countercurrent towers, and splash packing for cross-flow towers. In the case of counter-current towers, the program finds the liquid and gas flow rates which yield a minimum total annual cost. The design equations are in general form, with parameters read in by the program, so that experimental data can readily be used as it is accumulated.