Characterization and production of briquettes fuel from brewery wastewater sludge and sawdust

Energy is a vital input to the economic growth and development of any economic sector. One of the best-known and longest-used sources of renewable energy is biomass. Generating energy from forest resources opens the opportunity for  woodlands and other tree areas that can offer natural, environmentally-friendly energy to meet the needs of distant regions that would help protect  forest resources. On the other hand, the increases in wastewater for brewery treatment plants could result in a large amount of brewery wastewater sludge (BWWS) generation, which requires proper management before disposal. This research aimed to characterize and produce briquette fuel from the combination of sawdust and BWWS brewery using molasses as a binder. The Composite Briquitte was produced by varying the mixing ratio of sawdust to BWWS 100:0, 90:10, 80:20, 70:30, and 60:40, using 0 to 10% molasses as a binding agent. The proximate, ultimate and calorific value analyses of all composite briquettes were performed according to the American Society Testing of Material standard. It was observed that moisture content increased from 6.2% to 10.2%, fixed carbon decreased from 64.5% to 50.9%, and the caloric value decreased from 24.8 MJ/kg to 14.8 MJ/kg as the proportion of BWWS mixture in composite briquette increased. The binder ratio, hold time, and pressure effects and their interaction on the density and durability index of briquettes were investigated. The findings showed that the optimum density and durability indexes were 1019.99 kg/m³ and 97.274%, respectively, for the binder of 10%, hold time of 4.126 min and pressure of 6.076 MPa. It was concluded that the composite briquettes produced from 10%–20% BWWS proportion sawdust and the sawdust alone have high calorific values ranging from 20.9 MJ/kg to 24.8 MJ/kg, fixed carbon is from 61.18% to 64.5%, ash content is from 4.65% to 10.1%, volatile matter is from 20% to 24.85%, and moisture content is from 6.2% to 8.32%, which is guaranteed to be used  for household cooking.