BIODEGRADATION OF WASTE GAS CONTAINING TOLUENE BY USING AN EAF BLACK SLAG BASED BIOFILTER

Abstract

The steel industry generates large amounts of solid waste by-products. Electric arc furnace (EAF) black slag is the major by-product in steelmaking using EAF technology (90 % of total slag production). Its sustainable management remains a serious concern. If not recycled, the steel slag is disposed in landfills, thus increasing the amount of waste to be dumped. In this study, the use of this by‐product as packing material in biofilters is proposed as a novel alternative. Unlike traditional organic packing materials (e.g. compost or peat), this cube‐shaped material has a high mechanical resistance and a moderately rough surface with the latter promoting microorganism growth and attachment on its surface. As far as operating procedure is concerned, this inert media must be inoculated with an enriched microbial culture, and, a periodical supply of additional nutrients for microbial growth should be guaranteed. In order to analyze this carrier material´s behavior in biological systems, a bioreactor packed with EAF black slag is developed for treating toluene polluted air. After the start-up procedure for this bioreactor is established, the removal efficiency for inlet loading concentrations ranging from 0.5 to 3.0 gtoluenem–3 is determined for an empty bed residence time (EBRT) of 60 s.