Elimination of Methyl Ethyl Ketone in Air Streams by a Biofilter Packed with Fern Chips

摘要

A biofilter packed only with fern chips is developed for the removal of air-borne low-concentration volatile organic compounds emitted from copper clad laminate manufacturing processes using methyl ethyl ketone (MEK) as a solvent for resin lamination. The fern chip biofilters can sustain continuous operation for at least 4 years without turnover maintenance and avoid traditional media shortcomings such as compaction, drying, and breakdown, which lead to the performance failure of biofilters. Performance of biofiltration for the removal of MEK in a waste gas stream was studied in a pilot-scale biofilter that consisted of two compartments (each 40 cmW × 40 cmL × 70 cmH) arranged in one acrylic column. Each compartment was packed with fern chips to a volume of around 56 L (0.40 m2 × 0.35 mH). Experimental results indicate that using volumetric organic loadings of 60–115 g m−3 h−1, MEK removal efficiencies of over 91% were maintained for an operation period of over 120 days. Instant milk powder was essential for the good and stable performance of the biofilter for MEK removal. Economic analysis showed that for treating a gas flow rate of 12,000 N m3 h−1 with an average MEK concentration of 700 mg N m−3, the total cost of using the proposed biofiltration approach was less than 20% that of using the regenerative thermal oxidation method.