WEHRLE technology and process expertise was implemented because the existing flocculation/precipitation and conventional activated sludge process at Birrfelden was unable to treat the tanker cleaning waste effectively. Due to the high and extremely variable contamination levels in the tanker rinse water, biomass was regularly carried over in the final effluent. This caused a major problem, as it was not always possible to transfer this increased loading via the sewerage system to the local municipal sewage treatment plant.
During 1999 WEHRLE undertook extensive trials at Birrfelden using one of their fully automated pilot scale BIOMEMBRAT® membrane bioreactor systems. The WEHRLE process was trialled alongside alternative biological treatment systems and physico-chemical technologies. The pilot BIOMEMBRAT® system provided a consistently high quality, effluent and demonstrated low whole life costs in comparison to the alternatives.
Based on the effectiveness of the pilot trial on site and the extensive experience of WEHRLE in MBR applications, BERTSCHI decided to install the BIOMEMBRAT® technology. The high quality effluent produced from the WEHRLE system opens up the possibility of future recycling of the MBR effluent as process water.
Autor / Quelle: Gregor Streif / Hubert Wienands