Chemical removal of biomass from waste air biotrickling filters: Screeningof chemicals of potential interest

A protocol was developed to rapidly assess the efficiency of chemical washi ng for the removal of excess biomass from biotrickling filters for waste ai r treatment. Although the experiment was performed on a small scale, condit ions were chosen to simulate application in full-scale biotrickling filters . From 18 treatments with different combinations and concentrations of chem icals, only washing with 0.4% (w/v) NaOH, 0.26 and 1.31% (w/v) NaClO and 11 .3% (w/v) H2O2 resulted in a biomass removal significantly higher than trea tment with pure water with wet biomass removal efficiencies of 50.2, 49.2, 77.0 and 69.0%, respectively. Biomass removal by H2O2 and NaClO was accompa nied by complete loss of activity of unremoved biomass, whereas after treat ment with NaOH low residual biological activity was observed. However, trea tment with NaOH resulted in generation of relatively large amounts of suspe nded solids (22.3% of dry biomass removed) and dissolved carbon (65.3% of C -biomass removed). NaClO was found to be the most promising reagent for bio mass control in biotrickling fillers because of its ability to remove large amounts of biomass and its low cost. (C) 1999 Elsevier Science Ltd. All ri ghts reserved.