Biofilter performance of pine nuggets and lava rock as media

► Two alternative biofilter media (pine nuggets and lava rock) were compared. ► Three empty bed contact times and two moisture levels were tested. ► Lava rock had lower pressure drops and it settled down less. ► Gas phase reduction efficiencies of lava rock was higher than that of pine nuggets. ► Efficiencies were higher at 5 s empty bed contact time and high moisture level.