Large scale pilot plant for treating flocculated reservoir water and membrane integrity monitoring

The Wasserwerk des Kreises Aachen in Roetgen, Germany operates with financial help of the German Ministry for Education and Research and with scientific support of the IWW (Muelheim, Germany) a large scale membrane pilot plant. This pilot is equipped with twelve 6 m long pressure vessels resulting in a membrane area of about 1,620 m² to produce about 150 m³/h of filtrate. The pilot plant was operated first with flocculated reservoir water as feed. The results show that this is a reasonable process especially if the backflush water of the plant is further treated with another membrane plant to achieve high overall recoveries up to 98-99%. Monitoring of membrane integrity is an important topic in this research. Every pressure vessel of the pilot can be connected to a particle counter by switching magnetic valves automatically. Corrupted fibres were detected by particle counting after about 8 month of operation. A correlation between the number of broken fibres and particle concentration in the filtrate could not be established and may not exist as it is discussed in this paper.