Formation and inhibition of Polychlorinated-ρ-dibenzodioxins and dibenzofurans from mechanical grate municipal solid waste incineration systems

[Display omitted] •S-, P-, and N-containing inhibitors is tested in mechanical grate incinerator.•The inhibition efficiencies of total PCDD/F range from 45.77 % to 58.55 %.•Inhibition effect on catalytic metal, C- and Cl-source are clearly observed.•De novo synthesis is the stable inhibition pathway in this study. This study is carried out in two full-scale (300 t/d) municipal solid waste incinerators (MSWI), focusing on the inhibition effect on polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/F) formation by the Sulfur-, Phosphorus-, and Nitrogen-containing inhibitors. The inhibition efficiencies of total PCDD/F range from 45.77 % to 58.55 %, meanwhile, from 50.1 % to 57.6 % for toxic PCDD/F. X-ray photoelectron spectroscopy results conduct the inhibition effect on the three key factors of PCDD/F formation: catalytic metal, carbon source and chlorine source. Inhibitors can increase the proportion of inorganic chlorine form at the ash surface. The changes of sulfur and phosphorus forms support the inhibition mechanisms of PCDD/F. De novo synthesis is the stable inhibition pathway in this study, meanwhile, the chlorophenols-route and dibenzodioxin and dibenzofuran chlorination also work in some tests. The results are the basics for further industrial application of PCDD/F inhibitors and benefit in controlling the PCDD/F emission from MSWI.