TOWARDS DESIGNING SUSTAINABLE URBAN WASTE-WATER INFRASTRUCTURES - A SCREENING ANALYSIS

Whether sustainability can, or should, be defined in a practical opera tional sense, it is clear that the emergence of such a notion has prom pted what seems to be a profound re-thinking of whether our society, e conomic system, and technology are as we would wish them to be. Sustai nable development, clean technology, life-cycle analysis, pollution pr evention, and so on, are expressions of a willingness to leave no ston e unturned, as it were, in the search for what would be appropriate. W ith respect to the design and operation of a city's wastewater infrast ructure, in particular, this search is characterised by a seeming expl osion in the possible combinations of appropriate technologies, gross uncertainty about how novel technologies - only now emerging - might p erform in the very long term, and a continuing absence of specific cri teria of sustainability for determining the grounds on which any candi date technology might be preferred over another. The paper introduces a simple computational procedure for generating and screening candidat e combinations of unit-process technologies for an urban wastewater in frastructure. This is based on the use of Monte Carlo simulation, with the identification of those specific technologies (and combinations t hereof) that appear to have the greatest probability of being selected for use under different, possibly evolving, criteria of sustainabilit y. Application of the procedure is illustrated with respect to just a part of this infrastructure, i.e., the wastewater treatment plant. (C) 1997 IAWQ. Published by Elsevier Science Ltd.