Co-combustion of sewage sludge and Trakya lignite: the effect of blending on combustion characteristics

Abstract

Dried municipal sewage sludge, which is an unwanted by-product of wastewater treatment, has high organic content and relatively high calorific value. These characteristics make it a potential biomass energy source. Co-combustion of coal and sludge provides advantages such as waste reduction, energy recovery and destruction of organic pollutants and pathogens. This work investigated the combustion characteristics and gas emission profiles of Trakya lignite, sewage sludge, and their blends (70 and 85 wt%). Ignition temperatures and the temperatures where maximum mass loss observed were shifted to lower temperatures with the addition of sludge to coal. The predicted and measured TG/DTG profiles of blends were compared to investigate the interactions between sewage sludge and coal during co-combustion. A synergistic effect was observed during co-combustion for both blends. The synergistic effect increased with the increase in the sludge/coal ratio in the blend.