Production of Densified Biomass Fuel from Sludge Derived from Brewery Wastewater Treatment Systems

Abstract

Wastewater treatment sludge is classified as an organic sludge with high energy potential. Its key properties for biomass pellet production include very high moisture content, high organic matter content mainly composed of carbon, hydrogen, and nitrogen, and a moderate heating value. This research investigated the utilization of wastewater sludge from the beer brewing industry to produce biomass pellets, aiming to valorize waste sludge and substitute natural energy sources. The morphological characteristics of the sludge were analyzed using a Scanning Electron Microscope (SEM), which revealed an irregular surface featuring numerous voids and micro-cracks. The results from SEM-EDS and XRD analyses were consistent, indicating that the overall composition of the wastewater sludge consisted of 3 major elements: Si, Al, and Ca. These findings demonstrate that the sludge used in this study is suitable for combustion as a raw material for biomass pellets. Furthermore, combustion characteristic tests of various ratios between the wastewater sludge and teak sawdust showed that the 25:75 ratio yielded the highest heating value of 17.24 ± 0.84 MJ/kg, with a moisture content of 1.29 ± 0.24 wt% and an ash content of 16.04 ± 0.59 wt%. The experimental results indicate that wastewater sludge is a viable waste material that can be developed into value-added biomass pellets, serving as an alternative energy form that reduces dependence on fossil fuels and mitigates air pollution in the future.