NOVELTY - Treating a syngas stream, comprises: quenching the crude syngas stream (119) with a liquid stream to cool the syngas stream and remove at least one member comprising particulates, tars and/or other heavy hydrocarbon compounds; co-scrubbing the syngas stream to remove both hydrochloric acid and ammonia from the syngas stream; removing additional particulate matter from the syngas stream; and removing sulfur from the syngas stream to form a clean syngas stream.    USE - The process is useful for treating a crude syngas stream for clean-up of the crude syngas stream having widely varying composition and particulate load arising from waste gasification (claimed) to provide clean syngas, which useful for power generation, liquid fuel or chemical manufacture, hydrogen production or other applications that utilize carbon monoxide and/or hydrogen.    ADVANTAGE - The process provides treatment of high particulate content of crude syngas stream and the presence of hydrochloric acid and ammonia in substantially similar concentrations to allow for co-scrubbing and effective sulfur removal.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a syngas stream treatment system, comprising a syngas stream quenching sub-system for quenching the syngas stream syngas, a co-scrubbing sub-system for removing hydrochloric acid and ammonia from the syngas, a particulate removal sub-system for removing particulates from the syngas; a sulfur removal sub-system for removing sulfur from the syngas; and where the syngas stream quenching sub-system, the co-scrubbing subsystem, the particulate removal sub-system, the sulfur removal sub-system and an optional mercury removal system are operably arranged to remove hydrochloric acid, ammonia, particulates, sulfur, and mercury from the crude syngas stream to form a clean syngas stream.    DESCRIPTION OF DRAWING(S) - The figure shows a gas treatment system.    Power generation system (107)    Crude syngas stream (119)    Clean syngas stream (121)    Quenched syngas stream (207)    Co-scrubbing sub-system (209)