This program investigates the problem of human sewage waste and the biological and chemical methods involved in proper treatment. It also examines the costs and benefits of these processes and the health and safety issues for their operators. As there are various methods of treatment and disposal the program shows a marine-based system (Geelong) and an inland system (Bendigo). Both cities are developing world-class effluent systems adapted for their individual requirements. An advanced version, which includes 7 minutes of detailed graphics of the chemistry involved in these processes, is also available.