Design manual for waste stabilization ponds in Mediterranean countries

Waste stabilization ponds (WSP) are an extremely appropriate, sustainable and efficient method of wastewater treatment in many situations in Mediterranean countries. In several countries of the Region, wastewater is generally too valuable to waste and the reuse of pond effluents for crop irrigation or for fish culture is important in the provision of high quality food. This manual provides a comprehensive guide for design, operation and maintenance, monitoring and evaluation, and upgrading of WSP systems in Mediterranean countries in order to encourage their use. Recent developments in WSP technology, with an emphasis on wastewater storage and reuse, and a brief overview of the function and operation of each principal pond type are outlined. The manual also reviews present WSP usage in Mediterranean Europe, the Eastern Mediterranean and North Africa, where it is most developed. A detailed description of the process design of different types of pond (anaerobic, facultative, and maturation) together with design examples (Annex I) is followed by details about the physical design of ponds and their operation and maintenance requirements. Recommendations for routine effluent quality monitoring and WSP performance evaluation are also included. A description of pond rehabilitation and upgrading is followed by a discussion of wastewater storage and treatment reservoirs, which are appropriate in arid and semi-arid areas when treated wastewater is in high demand for crop irrigation. The manual concludes with a review of agricultural and aquacultural use of treated effluents, emphasizing measures necessary to protect public health.