Calculation of optimal gas retention time using a logarithmic equation applied to a bio-trickling filter reactor for formaldehyde removal from synthetic contaminated air

Formaldehyde (FA) removal from contaminated air has been extensively studied using a bio-trickling filter reactor (BTFR). However, the effect of different volumetric air flow rates (VAFRs) on FA removal efficiency needs to be verified for better BTFR design with optimal operating conditions. This study uses a laboratory-scale BTFR, operating with the three different VAFRs to remove FA from synthetic contaminated air. Mathematical models to determine the optimal retention time of contaminated air flow through the BTFR system are developed. The effect of different pH values on the FA removal efficiency is evaluated. FA removal efficiencies of 99, 96 and 95% are verified for VAFRs of 90, 291 and 1512 L h−1, respectively. Optimal retention times of 141, 50 and 26 s are verified for BTFR experiments operating at 90, 291 and 1512 L h−1 VAFR, respectively. The logarithmic models are proposed as a new approach for determining the optimal retention time and hoped to make a significant contribution to future biotechnological developments and air quality improvement analysi