Figure shows the results of the flushing and flooding trials, where the total gas flowrate at the reactor outlet, F out , is used as an indicator of reactor performance. The F out was recorded continuously using the BPC ® µFlow Gas flowmeter connected with a data logger. Because there was a net reduction of gas moles due to the biomethanation reaction, a lower flowrate at the reactor outlet indicated a higher conversion while higher flowrate values indicated a relatively lower conversion. Right after, either the flooding or flushing there was a transient period of relatively higher flowrate at the reactor outlet that showed that both methods lowered the conversion for a certain duration. This was due to the buildup of a thicker water film that increased the mass transfer resistance. The conversion recovers after the media had drained down the sump. For the case of non-continues trickling, both flooding and flushing showed a transient period that lasted for approx. 24 h, as shown in Figure . For the The trials with no trickling after the flushing and flooding showed the efficacy of these nutrient supply methods over time. The results showed that after the transient period is over the conversion in the reactor is stable for a limited time, as shown in Figure . The stable period was approx. 60 h after which the outlet gas flowrate started increasing indicating the beginning of nutrient limitation. In comparison, in the trials where media was continuously trickled after the flushing and flooding the stable period lasted for 150 h, as shown in Figure , after which the flooding or flushing activity was done again. This showed that the combined method of continuous media trickling along with either the flushing or flooding was the best method for the supply of nutrients. Using this combined methodology, the transient period was relatively shorter, and the stable period was increased from 60 h to 150 h.