Investigation of Pearl Millet Stacks and Polyurethane Foam as Packing Material for the Removal of Volatile Organic Compounds from Tannery Effluent through Biofiltration for Environmental Application

Abstract

The leather tanning industry plays an important role in the economy, is a significant source of environmental pollution due to the release of volatile organic compounds (VOCs) such as benzene, toluene, xylene (BTX) in addition to other chemicals. This study focuses on the feasibility of using pearl millet stacks, a sustainable and locally available agricultural by-product, polyurethane foam and the mixture of the above in 1:1 ratio as packing materials in a biofiltration process and examine their removal efficiency towards certain VOCs from tannery effluent. A custom-built-up flow biofilter is studied with microorganism inoculated packing material to evaluate the removal efficiency and elimination capacity under varying flow rates, inlet VOC concentrations and operational durations. The results show that pearl millet stacks exhibit superior removal efficiency (up to 95%) compared to polyurethane foam and the mixed bed. The removal efficiency reaches the maximum after 15–16 days of operation, which indicates the critical role of microbial acclimatization. The efficiency is observed to differ at various flow rate of the effluent, inlet loading rate (ILR). The results obtained demonstrates pearl millet stack as the promising biofilter bed for the effective removal of VOCs from tannery effluent.