Ten Years of Operation of Rio De Janeiro'S Ipanema Submarine Outfall

Details are given of the design and construction of the prestressed-concrete ocean outfall serving a large area of Rio de Janeiro, Brazil, which was put in operation in 1975. The maintenance of the outfall, including repairs necessitated by a number of accidents, is described. Regular monitoring of the receiving waters had been carried out since 1974, and the results of such monitoring up to 1985 are summarized. Particular emphasis is placed on grease, coliform bacteria, and hydrobiological indicators of water quality. The results show a marked improvement in water quality since the outfall was put into operation, but beaches in the area continue to be polluted by storm-sewage overflows. The water quality standards developed for various beneficial uses are tabulated.