The selection of the sewage sludge dumping site in the Firth of Clyde off Garroch Head is compared with the selection of sites near Bell Rock and St. Abbs Head off the Forth Estuary, Scotland, almost three-quarters of a century later. Details are given of the special shore facilities which are required to dispatch sewage sludge to sea, and specific features of purpose built sludge ships are described. Reference is then made to the factors involved when discharging sludge at the sea dumping site. The emphasis in the paper is on the engineering aspects of the facilities required and operations involved in the sea disposal of sewage sludge.