Characterization and evaluation of poplar and pine wood in twin biotrickling filters treating a mixture of NH3, H2S, butyric acid, and ethylmercaptan

Biotrickling filters for waste gas treatment are often packed with expensive, inert packing materials. In this work, poplar and pine wood chips were evaluated as low-cost packing materials in two biotrickling filters for the simultaneous treatment of a mixture of organic and inorganic volatile compounds. Bioreactors were operated at gas contact times of 22–34 s. Inlet loading rates of 3.5 ± 1.0 gN-NH3 m−3h−1 and 6.5 ± 1.1 gS-H2S m−3h−1 were supplied, while ethylmercaptan and butyric acid were fed at loads of 3.6 ± 1.2 and 6.0 ± 2.1 g m−3h−1, respectively. A thorough characterization of both packing materials revealed some differences in the physical–chemical properties, mainly in their water retentivity and buffer capacity. Despite of such differences, both bioreactors performed similarly. Bioreactors were able to achieve complete removal of NH3 and butyric acid, while H2S and EM removal efficiencies over 90% and 70%, respectively, were found. N-species analyses in the leachate proved high nitrification rates in both biotrickling filters. Control of pH was essential for maintaining nitrification activity. Other oxidation processes were hardly affected by pH changes. Both woods showed potentially attractive as packing materials for biofiltration. Thus, availability and durability of woods are decisive factors to tip the balance. The work compares the performance of two biotrickling filters packed with two types of wood chips commonly used in biofilters. No previous works have directly compared the performance of two types of woods in biotrickling filters for the treatment of a range of organic and inorganic odorants because biotrickling filters are commonly packed with inert packing materials. Results indicated that the two types of woods tested behaved similarly and, more interestingly, showed equivalent treatment capacities than that of inert packing materials in the removal of a range of typical pollutants in odorant waste gases. Research is of particular interest for improving biofiltration knowledge. In addition, this research has large practical implications in the cost-benefit of full-scale biotrickling filtration systems because inorganic packing materials commonly used in biotrickling filters are much more expensive than organic packing materials. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 171–179, 2017