ABSTRACT
Upflow anaerobic sludge blanket reactors (UASBs) are high-rate anaerobic wastewater treatment units. They were developed in the 1970s by Professor Gatze Lettinga at the University of Wageningen in The Netherlands, and they have been extensively tested at full-scale in tropical and subtropical regions, particularly in Brazil, Columbia and India (van Haandel and Lettinga, 1994; Foresti, 2002*; for an excellent on-line introduction to UASBs, see Field and Sierra, 2002*). They are used for the primary treatment of domestic wastewaters and high-strength biodegradable industrial and agro-industrial wastewaters. They have also been found satisfactory for the treatment of mixed domestic and industrial wastewaters in Mauritius (Dean and Horan, 1995*). However, an alternative view of their performance and applicability in developing countries (at least in Kanpur, India) is given by Sharma (2002*).
