The objectives of this project were: 1) to ascertain the feasibility of using a two-stage foam separation system, with foam fractionation or air flotation as the second stage, to treat a tarsand extraction wastewater; and, 2) to evaluate the effects of four operational variables on the second stage performance. The wastewater was a tar-in-water emulsion collected during a steamflood extraction experiment conducted by the Department of Energy's Laramie Energy Technology Center on a tarsand deposit in eastern Utah. The four operational variables considered were chemical dose, hydraulic detention time, air flowrate, and temperature. To achieve these objectives a two-stage system was devised. In the first stage, polymer-aided air flotation removed the bulk of the tar. With the second-stage foam fractionation system, 16 trials were conducted using the cationic surfactant, EHDA-Br. In the second-stage air flotation system, 24 trials were conducted, eight with no polymer addition and 16 with the addition of the low molecular weight, strongly cationic polyelectrolyte, Betz 1195. Ten trials were then conducted at the set of conditions believed to give the best treatment of the water. The effluents were tested for TOC, COD, suspended solids (SS), and total solids. It was found that either of the two-stage systems would give TOC, COD, and SS reductions greater than 98 percent, although the polymer-aided air flotation system was found to be the best second stage process. The replicate trials consistently produced data very close to the best treatment achieved in the experimental trials, thus showing the reproducibility and stability of the two-stage process. / M. S.