Influence of input waste feedstock on solid recovered fuel production in a mechanical treatment plant

Abstract

In solid recovered fuel (SRF) production, type and nature of input waste stream influences the quality of fuel product. This paper presents the influence of input waste stream on SRF production in a mechanical treatment (MT) plant. The SRF was produced at industrial scale from three different types of waste streams: commercial and industrial waste (C&IW), construction and demolition waste (C&DW) and municipal solid waste (MSW). Here, the stream of MSW used for SRF production was energy waste collected from households. In the SRF production from MSW, higher yields of material were recovered in the form of SRF as compared with that of recovered from C&IW and C&DW. Of the input MSW to the MT plant, 72wt% was recovered as SRF, equivalent to 86% energy recovery. The energy consumed to produce unit tonne of SRF from C&IW, C&DW and MSW was 1153MJ, 1246MJ and 1626MJ, respectively. In the SRF production, removal of chlorine (Cl), lead (Pb) and mercury (Hg) from C&IW feedstock was worse than from C&DW and MSW feedstocks. In the SRF production from C&IW, of the input mass of chlorine, lead and mercury to the MT process 60%, 58% and 45%, respectively was found in the SRF. The SRF produced from C&DW contained the lowest mass fraction of the input chlorine, lead and mercury in comparison with the SRF produced from C&IW and MSW, namely 34%, 8% and 30%, respectively. Among the waste components rubber, plastic (hard) and textile (synthetic) were identified as potential sources of polluting and toxic elements, whereas wood, paper & cardboard and plastic (soft) were found to contain the lowest content of polluting and toxic elements. The pollutant and toxic elements investigated in this research work were chlorine, lead, cadmium, mercury and arsenic.