Direct nanofiltration or ultrafiltration of WWTP effluent?

From August to December 1999, DHV Water BV (DHV) conducted a study at the Driebergen sewage treatment plant of the technical feasibility of effluent post-treatment to achieve Maximum Acceptable Risk (MAR) quality. The study was commissioned by the Stichtse Rijnlanden District Water Authority and the part of the study concerned with membrane filtration was conducted in co-operation with Stork Friesland. This article provides a brief description of the study results achieved using the two membrane filtration units. Conducting the studies simultaneously enabled proper comparison of product quality, technical operational management and the costs of ultrafiltration and nanofiltration. The article attempts to answer the question of how far new developments in membrane technology provide prospects for producing water with a genuine added value.