Control of sulfur dioxide emission from a coal-fired power generating boiler using a cocurrent venturi-type scrubber in series with a wetted film packed tower was studied in a one-thousand cfm pilot system. Sulfur dioxide absorption characteristics were studied in detail with three types of alkali materials, calcium oxide, sodium carbonate and calcium carbonate. Sulfates lime/fly ash and dolomitic lime were also tested and their absorption properties were compared to the calcium oxide results. The primary objectives were the development of design data for predicting sulfur dioxide absorption in a venturi scrubber with limestone-injection wet scrubbing and a combination of a venturi scrubber and packed tower with direct lime/limestone wet scrubbing. A simplified method for expressing the SO2 absorption was developed with standard linear correlation techniques. Process parameters relevant to the type of absorption device were studied so that the SO2 absorption efficiency could be estimated for similar operating systems. (Author)