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

Abstract

An inorganic-based bed biofilter was used to eliminate methane (CH4) from an air stream under pseudo steady state, transient state (shock loads), and starvation conditions. Under pseudo steady state conditions, the effect of inlet CH4 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 CH4 starvations were evaluated. The biofilter performance was promising for the treatment of a wide range of concentrations of off gas emissions polluted with CH4 (1000–13,000 ppmv). For CH4 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.