Proceedings

The interest in tertiary treatment within wastewater treatment plants has increased due to strict effluent legislation introduced by the European Water Framework Directive (EWFD, 2000/60/CE). This requires a significant improvement of the existing treatment plant performance with the focus towards removal of nutrients. Moving bed tertiary sand filtration such as ASTRASAND® biofiltration (ref [2]) can help to comply existing sewage treatment plants with particularly nitrogen discharge limits. Tertiary removal of ammonia & nitrate (< 1 mg/l), phosphate (< 0.1 mg/l), suspended solids and BOD by means of ASTRASAND® biofiltration has been implemented successfully at a large number of schemes. The system is an add-on tertiary process, hence the infrastructure of the existing plant can remain virtually unchanged. Moreover, the filters are modular in design, making future upgrades of the plant easy. In this paper we would like to share operational results of both nitrifying and denitrifying plants with you. Moreover we present new features to refurbish and optimise existing – designed for TSS removal only – tertiary moving bed filters or to upgrade them for better performance or higher capacities.

KEYWORDS Biofilm, modelling, moving bed sand filter, nitrification, denitrification, tertiary treatment, process optimization, automated monitoring, future developments, innovation, ASTRASAND