Biodegradation of vapour phase benzene, toluene and xylene (BTX) using compost based modified biofilter medium

Abstract

One of the most challenging problems to use the biofilters at industrial scale is continuous supply of nutrients in the operation. Another problem associated with natural material, such as, compost, which is otherwise an excellent medium, is its low durability, more compaction and poor strength. To overcome these problems a modified compost based medium was prepared. In preparation of the medium, essential nutrients along with binders were added to overcome the above listed problems. The characterization results show that modified media had better properties as compared to the compost. The testing of the modified medium was carried out in laboratory scale biofilter against mixture of vapour phase benzene, toluene and xylene (BTX) as targeted pollutants. No nutrient except water was supplied during the whole experiment. The maximum overall removal efficiency (RE) of 95.83% was achieved at a total BTX loading rate of 549 g m-3 h-1. Further, a maximum elimination capacity (EC) of 983.9 g m-3 h-1 was obtained at a total BTX loading of 1312.19 g m-3 h-1 with an empty bed residence time (EBRT) of 18.5 sec. The results show maximum removal efficiency for toluene, followed by benzene and xylene. During whole operation of 57 d, no deterioration in the medium was observed.