Performance of a styrene-degrading biofilter inoculated with Pseudomonas sp. SR-5

Styrene removal was studied for 3 months in a laboratory-scale biofilter packed with a mixed packing material of peat and ceramic at a ratio of 1 to 1 on a dry-weight basis and inoculated with Pseudomonas sp. SR-5. More than 90% removal efficiency (RE) was attained at 1-140 g/m3/h styrene loads under nitrogen-source limitation. When RE decreased to 70% after 30 d with an increase in styrene load, readdition of SR-5 and washing of the filter packing material restored the RE to more than 90% by maintaining the population of SR-5 at 1-10% of the total cell number. The maximum elimination capacity (EC) by kinetic analysis was estimated to be 290 g/m3/h. High conversion of the removed styrene carbon to CO2, and significantly small production of cell mass from the removed carbon were confirmed.