Performance Evaluation of a Methane Biofilter Under Steady State, Transient State and Starvation Conditions

An inorganic-based bed biofilter was used to eliminate methane (CH 4 ) from an air stream under pseudo steady state, transient state (shock loads), and starvation conditions. Under pseudo steady state conditions, the effect of inlet CH 4 concentration in the range of 1000–13,000 ppmv on the biofilter performance was studied. The air flow rate was kept constant at 3 L min −1 , corresponding to an empty bed residence time (EBRT) of 6 min. The flexibility of the biofilter under transient conditions was evaluated by two strategies: Inlet loads (IL) varied from 13 to 65 g m −3 h −1 by changing inlet concentrations from 2000 to 10,000 ppmv or by changing air flow rates varied from 3 to 15 L min −1 , separately. Finally, the effects of nutrients and CH 4 starvations were evaluated. The biofilter performance was promising for the treatment of a wide range of concentrations of off gas emissions polluted with CH 4 (1000–13,000 ppmv). For CH 4 concentrations ranging from 1000 to 4000 ppmv, the removal efficiency (RE) remained higher than 75 %. The maximum elimination capacity (EC) obtained in this study was 45 g m −3 h −1 for an IL of 87 g m −3 h −1 . In case of sudden variations of ILs (13 to 65 g m −3 h −1 ) either by changing the inlet concentration or by modifying the flow rate, the responses of the biofilter were almost instantaneous.