The self-flocculating property of Chlorococcum sp. GD was firstly reported.
Chlorococcum sp. GD had excellent flocculating ability.
The excellent flocculating ability of Chlorococcum sp. GD was related to EPS.
Pollutants in secondary effluent were effectively removed by Chlorococcum sp. GD.
The lipid content of Chlorococcum sp. GD was high.