The growth of microalgae was investigated using diluted process water from an animal waste treatment plant as a substrate. Batch experiments were carried out to determine the growth characteristics of three microalgae strains: Microcystis aeruginosa, Chlorella vulgaris and Euglena gracilis. The two types of process water with different dilution rates were used for the experiments. The biokinetic parameters of each culture were estimated from the logistic growth curves for comparative analysis. In aerobic effluent, most growth parameters were significantly better than in anaerobic effluent regardless of the dilution rates. This suggests that the concentration of organic matter, such as volatile fatty acids, affects microgal growth. Euglena gracilis, which was the largest in size, had the highest growth rates among the three species in both pure and mixed cultures.