Biodrying for fuel recovery from sewage sludge: An integrated evaluation by ultimate and proximate analyses

Abstract

This study investigates the utilization of the biodrying process, which is an eco-friendly approach for sewage sludge management to produce a fuel-like product.Biodrying tests were conducted for six trials containing different amounts of bulking agents (straw and sawdust). Higher volatile matter removal was achieved for trials with sawdust as a result of better porosity conditions. Consequently, biodrying indexes were higher for straw containing trials (7.73-30.85) with straw than those trails with sawdust (6.94-13.99). Trials with straw resulted in biodried materials with lower moisture content and higher calorific value due to lower water holding capacity of straw. However, sawdust provided better fuel quality due to the higher bulk density of the product. Thus, fuel value indexes determined for trials with sawdust (81.62-152.17) were remarkably higher than those of trials with straw (16.02-68.97). Furthermore, biomass characterization indexes (>25.000) indicated that products with sawdust can be used as promising alternatives to biomass such as wood chips and wood chunks in combustion facilities.