Abstract: An apparatus and method for wet pre-treatment of an effluent gas derived from upstream semiconductor or LCD manufacturing tools before the effluent gas is processed in an effluent gas treatment system in provided. The apparatus comprises an atomizing spray nozzle for atomizing a reagent and a processing section in which the effluent gas in pre-treated with the atomized reagent using a cyclone method. The processing section comprises an inner tubular portion and an outer tubular portion. The processing section has an effluent gas inlet, a reagent inlet, an effluent gas outlet, and a waste liquid outlet. An apparatus is also provided which includes a plurality of wet pre-treatment units, each of which pre-treat each of effluent gas streams derived from a plurality of CVD chambers.