4. Conclusion
This research examined in detail, the concentration of inorganic elements in various streams of material produced in commercial scale solid recovered fuel (SRF) production process and components of input waste. The SRF was produced from commercial and industrial waste (C&IW). The elemental balance of SRF production process was calculated by using material flow analysis (MFA) methodology. The potential source material of pollutant and potentially toxic elements in the components of C&IW stream are traced and identified.
Of the total input chlorine, arsenic, cadmium, lead and mercury content to the process 60%, 32%, 46%, 58% and 45% respectively was found in the SRF stream. Among the components of C&IW, rubber and plastic (hard) were measured to contain the highest content of chlorine (i.e. 8.0 wt% and 3.0 wt% respectively) and identified as potential source of chlorine. Rubber also contained high content of cadmium as compared to the other components. Plastic (hard) was measured to contain higher content of lead as compared with other components of input waste stream.
The distribution/sorting of rubber, plastic (hard) and to some extent textile components played key role in defining the concentration of pollutant and potentially toxic elements in output streams of SRF production process. A considerable mass fraction of paper and cardboard and wood found in the reject stream could have effectively reduced the overall concentration of pollutant and potentially toxic elements of SRF, if those were sorted and put into the SRF stream instead of ending up in reject material stream. The elemental based sorting of waste components is required in order to further reduce the content of pollutant and potentially toxic elements in the SRF stream.