.     Background to the Doyle Report

The Working Party on the Disposal of Sewage Sludge to Land, set up by the Department of the Environment in February 1974, recommended that a critical survey of the literature on sludge disposal to agricultural land was needed. It was also envisaged that examination of sites in the United Kingdom which had a history of sewage sludge application, would enable criteria to be developed, which would be of use in the formulation of guidelines for the disposal of sewage sludge to agricultural land or the amendment of existing guidelines, pending the results of ongoing research projects.

The review has been limited in large part to an examination of the value of sewage sludge to agricultural production and to reviewing the existing knowledge of the effects of potentially toxic elements which occur in sewage sludges, on soils and plants. Only a brief mention of pathogenic organisms is included as this subject is presently receiving a great deal of attention elsewhere.

Since the commencement of the contract under which this review was prepared, the Report of the Working Party on the Disposal of Sewage Sludge to Land (55) has been published.

This review supplements the information contained in the Working Party Report and it is hoped will be of assistance to the Standing Committee on the Disposal of Sewage Sludge, which in 1975 superceded the Working Party, in evaluating the current situation in the light of existing knowledge, both theoretical and practical.