Carbon mass balances and estimated carbon accumulation rates (C_ACC) in the biofilters at varying methane inlet loads (IL).

Note: The carbon entering biofilter 1 and 2 (CIN) was the methane introduced to the system (CH4)IN and the carbon dioxide in the inlet air (CO2)IN. The carbon introduced via methanol in the nutrient solution was less than 0.04 g C m−3 h−1 and was therefore neglected. The carbon exiting biofilter 1 and 2 (COUT) consisted of the unconverted methane, (CH4)OUT and the carbon dioxide leaving the system (CO2)OUT.