AWWA JAW18172

Study of the water of Chichester Dam, operated by the Hunter District Water Board in New South Wales, Australia, indicated that the supply could possibly be treated by direct filtration at capital and operating costs well below those for conventional treatment. Extensive pilot-plant testing carried out to determine the feasibility of direct filtration included optimization of the media and of the chemical system, evaluation of declining-rate versus constant-rate filtration, and use of artificially manufactured "dirty water." The treatment process selected as a result of these pilot studies was constant-rate direct filtration, with mechanical in-line chemical mixing and no flocculation. Includes 13 references, tables, figures.