Micropollutants: A bottleneck in sustainable wastewater treatment

Every year a variety of xenobiotic chemicals as pesticides, dyes,... are introduced on a very large scale. The majority of these compounds have a rather poor biodegradability. Hence, fresh water resources become more and more contaminated with micro-quantities of these man-made pollutants. Moreover, some of these obscure pollutants may have the undesirable capability of having oestrogenic activity on various high forms of life. This paper deals with the problems of micropollutants in drinking water production and wastewater treatment. The biocatalytic properties of microorganisms can be limiting for several reasons such as lower threshold values for metabolism, insufficient free energy change or inadequate metabolic knowledge base in the microbial cell or community. The limiting biodegradative capacity of natural microbial associations necessitates the development of more integrated water treatment and management. Research is necessary on two levels i.e. the search for biotechnological processes able to remove such chemicals through engineering of pathways and microbial associations, and the need for reliable biosensors able to generate information on residual microorganics. Trends such as improved biocatalysis and accurate process control are of major significance. However, a clear-cut scientific and political endorsement of the necessity to use reclaimed wastewater is of prime importance to evolve towards sustainable water treatment and management. (C) 1997 IAWQ. Published by Elsevier Science Ltd.