Before it was decided to proceed with this Irrigation and Drainage Paper in its present form, FAO commissioned a number of papers from different authors with a view to editing them into a suitable document. However, this approach did not achieve the range of coverage required and many of the original papers submitted were not used in the preparation of this document. Those that were used were edited to fit in with the needs of the Paper and are properly referenced in the text. FAO and the editor wish to acknowledge in particular the following contributors: Messrs. S.S. Al-Salem, T. Asano, H. Bouwer, H. Shuval and G. Tchobanoglous. A draft of this document was reviewed in an Expert Consultation on Safe and Efficient Irrigation with Treated Sewage Water organized by the FAO Regional Office for the Near East held in Rome in March 1991, and the comments and recommendations of the Expert Consultation have been incorporated into the text as appropriate.
The editor wishes to express his gratitude to Dr. A. Arar, former Senior Regional Officer of the Land and Water Development Division, FAO, for initiating the preparation of this document and his encouragement. Following Dr. Arar's retirement, Dr. A. Kandiah, Technical Officer of the Land and Water Development Division took on the responsibility for completion of the Paper and the editor is indebted to him for his encouragement and support. Dr. Kandiah also contributed significantly to Chapter 5.
The editor wishes to acknowledge the assistance of Ms. Alison Smith and Ms. Sandra Dodd, for without their dedication and hard work it would have been impossible to produce such a satisfactory document. Finally, acknowledgement is made to Ms. C.D. Redfern for preparing the material in final camera-ready copy to conform with the format of the FAO Irrigation and Drainage Paper series.
It is hoped that this document will make a positive contribution to the extension of wastewater use in agriculture and the improvement of wastewater use practices. The paper is dedicated to the agricultural workers and consumers of agricultural products who will benefit wherever wastewater might be used with greater control in the future.