BACKGROUND Although microalgae had been widely used in wastewater treatment, the treatment efficiency is affected by the carbon limitation of the carbon/nitrogen (C/N) ratio in wastewater. In the present study, the performance on nutrients removal and biomass production was investigated when Chlorococcum sp. GD was inoculated into non-sterile municipal wastewater and cattle farm wastewater. RESULTS Although wastewater had indigenous microalgae and bacteria, microalgae could grow and the growth of indigenous bacteria was inhibited when exogenous Chlorococcum sp. GD was inoculated into non-sterile municipal wastewater and cattle farm wastewater. Nevertheless, both biomass production and nutrients removal were relatively low due to the low C/N ratio in both wastewaters. When sodium acetate was supplemented to both wastewaters in the late exponential growth stage, biomass production and nutrients removal were enhanced. Moreover, the lipid accumulation from microalgal cells grown in municipal wastewater and cattle farm wastewater were 33.2% and 20.9%, respectively. Linoleic and linolenic acids accounted for 47.64 to 56.41% of the total fatty acids, and were in great demand for dietary supplements and aquacultures. CONCLUSION Chlorococcum sp. GD could be a potential candidate for bioremediation of both wastewaters. The exponential sodium acetate feeding would be an efficient approach for enhancing biomass production and nutrients removal efficiency from wastewater with a low C/N ratio. (c) 2019 Society of Chemical Industry