Optimal conditions of different flocculation methods for harvesting Scenedesmus sp. cultivated in an open-pond system

► The Scenedesmus sp. discussed in this study was cultivated in an open-pond system. ► Optimal conditions of six flocculants for harvesting Scenedesmus sp. were discussed. ► Optimal pH to each flocculant was found for achieving high flocculation efficiency. ► Increasing algal biomass concentration will increase the flocculant dosage needed.