PCDD/Fs environmental impact from an anaerobic digestion treatment

The presence of mechanical-biological treatment (MBT) plants of municipal solid waste (MSW) in a territory could give significant contamination by dioxins and furans (PCDD/Fs). This study points out the importance of carrying out a preliminary environmental impact assessment for MBT plants. A preliminary investigation was carried out with reference to the anaerobic digestion (AD) of MSW. A dispersion model was applied to a MBT plant. The AD process was analysed as a treatment of the undersieve of screened residual MSW, before a post-biostabilisation (BS) step. A comparison with the BS of the oversieve alone was made too. A conventional biofilter and a regenerative thermal oxidizer (RTO) were also compared as emission control solutions. Thanks to the increased dilution by the RTO, lower impacts are expected on the surroundings. In addition, coupling AD with a post-BS results in considerably lower PCDD/Fs emissions with respect to BS alone.