The effects or energy input variation on the mixing obtained in a laboratory flocculation unit were studied. The main parameter was the size and shape or paddles used to induce the mixing. A variation in paddle geometry produced a variation in energy input. The effect of baffles was studied and the effect of flocculator geometry was considered by comparing two different length to width ratios tor a single tank. Theoretical models were used in an attempt to describe a flocculation unit by comparing the experimental tracer output with the predicted theoretical output. Some generally accepted design criteria tor full-scale flocculation units were also compared with experimental results. / Thesis / Master of Engineering (ME)