Particulate and gaseous emissions during fluidized bed combustion of semi-dried sewage sludge: Effect of bed ash accumulation on NOx formation

► Fluidized bed combustion of two different sewage sludges has been characterized. ► The conditioning agent used impacted the particulate and macro-pollutant emissions. ► Sludge with Ca-based agents shows nil SO2 and larger particulate and NOx emissions. ► NOx emissions may be correlated with ash accumulation inside the bed.