Analyzing the production, quality, and potential uses of solid recovered fuel from screening waste of municipal wastewater treatment plants

Over time, wastewater management evolves into a circular model, producing energy and moving towards zero waste. The usual screening waste treatment is the elimination, with no energy recovery processes. As an alternative, the production of solid recovered fuel (SRF) from screening has been studied, both non-densified and densified, in pellet form. The densification was developed, taking as variables the input moisture and size of the die, obtaining 20 different samples. The optimum pelletizing conditions are an input moisture content of 10% and dies with a compression ratio of 6/20, 6/24 and 8/32. SRF properties have been evaluated based on a quality proposal presented in this paper, which has been developed given the lack of uniformity in the existing SRF standards. The SRF produced complies with fuel quality requirements, such as lower calorific value, with values between 13.37 and 25.65 MJ/kg; Cl and Hg content, with maximums of 0.066% and 1.0 × 10−5 mg/MJ, respectively; and ash content, between 7.22% and 9.85%. Energy from waste plants could be the destination for all the SRF produced. Its use in cement plants and gasification processes, more restrictive than the previous one, would require manufacturing processes with adequate moisture levels and die size.