This paper first examines the experimental results from a 16-h plasma-assisted gasification trial for conversion of refuse derived fuel (RDF) into syngas suitable for biofuel production in a pilot plant. In particular, the work focuses on the effect on the concurrent ash vitrification and tar reforming processes on the general composition of a syngas stream produced in a fluidized bed gasifier. The effect of plasma on tar reforming is showed by continuous monitoring of gas composition before and after the plasma converter, with reduction efficiencies typically exceeding 99%v/v for most hydrocarbons, SO2, NH3, NOx, and organic sulfur. The test also investigates on the effect of plasma intensity on different contaminants reforming and syngas conditioning when varying the input power value at cracking-relevant temperatures. A simplified catalytic test is undertaken under continuous flow of cleaned syngas generated by the pilot plant to identify the short-term effects of waste-derived contaminants on catalysts activity when plasma refining is not operated.