The Use of Reagents in Up-flow Submerged Biofilters

This paper presents results concerning three wastewater treatment plants combining biological treatment (by upflow biofiltration) and chemical treatment in order to achieve: Suspended solids and phosphorus removal in a lamella settler before biofiltration enhancing dissolved organic matter removal and nitrification (Perroy — Switzerland).Simultaneous nitrification and phosphorus removal in biofilters, after adding Al salts and polymers at the inlet of the biofilters (Cologne — Germany).Denitrification in upflow biofilters, (Oslo — Norway) after chemical preprecipitationThe results show advantages of such an association which makes it possible to reach high effluent quality and reliability with respect to stringent standards (C, N, P).