Comparison of pressure-driven membrane processes and traditional processes for drinking water production in Europe based on specific impact criteria

Due to the policy of many governments of encouraging the use of alternative water sources instead of groundwater, there is a clear need for enhanced water purification systems such as pressure-driven membrane processes. In this article a comparison is made between drinking water production from surface water using pressure-driven membrane processes and using traditional surface water treatment systems. Three alternatives are considered: Traditional treatment using coagulation/flocculation, sand filtration, physicochemical softening, activated carbon adsorption and disinfection (Process A); spiral-wound nanofiltration with ultrafiltration pretreatment followed by marble filtration and disinfection (Process B); and direct capillary nanofiltration with only a limited pretreatment and post-treatment by marble filtration and disinfection (Process C). An evaluation protocol was used (CRIME-DAV), in which the following impact criteria were taken into account: Quality and public health, operational aspects, the environment; the landscape, the economy, and administrative, legal and societal acceptance. The comparison of these aspects shows that none of the considered alternatives is favourable for all aspects. In practice, weight factors used in the protocol may have to be revised, shifting the optimal solution to one of the three processes. The general comparison is to be considered a rough indication and a template for a more detailed practical study. Process A proved to be advantageous for the aspects \'environment\' and \'economy\' but performance for \'quality and public health\' and \'landscape\' was poorer than for alternatives B and C. The latter both had a particularly good performance for \'quality and public health\' and \"operational aspects\". Process C was more advantageous than B for economical aspects and the environment. WaterSA Vol.30 (3) 2004: 413-41