Treatment of volatile organic compounds from a typical waste printed circuit board dismantling workshop by a pilot-scale biotrickling filter

A pilot-scale biotrickling filter (BTF) was designed to treat volatile organic compounds (VOCs) emitted from a typical waste printed circuit board (WPCB) pyrolysis workshop. Measured by gas chromatography-mass spectrometry (GC-MS), the main components of VOCs and their concentrations were benzene, toluene, chlorobenzene, ethyl-benzene, xylene, styrene, benzaldehyde, and trimethyl-benzene. The removal efficiencies of the BTF for these compounds ranged from 81.1 to 97.8% after 90 days of operation. The maximum elimination capacity of 25.94 g/m(3) h was obtained with the inlet loading of 30.72 g/m(3) fixed the fixed empty-bed residence time (EBRT) of 9.80 sec. Hazard ratio index based on threshold limit value for time weighted average (TLV-TWA) and VOCs concentrations indicated that the cancer risk of VOCs was significantly reduced after the BTF treatment. The microbial community analysis revealed initial inoculum and some emerging bacteria played crucial roles in the improvement of BTF performance with the biodegradation of this kind of VOCs by the polymerase chain reactiondenaturing gradient gel electrophoresis (PCR-DGGE) technique and pyrosequencing analyses indicated that proteobacteria phylum was the dominant in the BTF. All above results indicated that VOCs with multicomponent and fluctuant concentrations from a typical waste printed circuit board pyrolysis workshop were removed efficiently and in an environmentally friendly way by the biofiltration method.