The role of bryophytes in an indoor air biofilter
Chamber experiments were conducted to evaluate the role of living bryophytes as a biofilter substrate for degrading volatile organic compounds (VOCs) at typical indoor concentrations. The biofilters reached equilibrium with VOC concentrations in 0.25h indicating that sorption will have an inconsequential role in contaminant removal over time. 'Eurhynchium riparoides' and 'Anomadon minor' were tested as candidate species. Results showed very little effect of additional water (above the desiccation point) on degradation. 'E. riparoides' removed 50% of influent toluene while 'A. minor' removed 10%. When methylethylketone (MEK) was present in addition to toluene, respective removal rates in 'E. riparoides' biofilters were 50 and 20% suggesting a suppression of toluene removal. Isolation cultures revealed a fungus, 'Fusarium oxusporum ', that could efficiently degrade MEK. It may have been possible that the fungal community suppressed the toluene degraders. Neither species had an impact on trichloroethylene concentrations. Maximum MEK and toluene elimination reached 7·10-1 and 1·10-3 mol·g-1·h-1 which compare favourably to other biofilters. 'E. riparoides' has shown promise as an indoor air biofilter substrate.