Two microalgae, Chlorella vulgaris and Scenedesmus acuminatus, were batch cultivated separately in two types of diluted liquid digestates. The first digestate (ADPP) was obtained from a mesophilic laboratory digester treating biosludge from a pulp and paper industry wastewater treatment plant. The second digestate (ADMW) was collected from a full-scale mesophilic anaerobic digester treating-mixed municipal wastewater treatment sludge. The highest biomass production (as volatile suspended solids, VSS), 8.2–9.4 g L−1, was obtained with S. acuminatus in ADPP. C. vulgaris in ADMW had the lowest biomass production, reaching 2.0 g L−1. Both microalgae removed ammonium efficiently from ADPP (99.9% removal) while the final ammonium removal efficiencies from ADMW with S. acuminatus and C. vulgaris were only 44.0 and 23.8%, respectively. The phosphate removal efficiencies from both ADPP and ADMW were higher than 96.9% with both microalgae. The highest carbohydrate content (60.5%) was obtained with S. acuminatus cultivated in ADPP. Scenedesmus acuminatus in ADPP showed one of the highest biomass production yields that have been reported for microalgae in real wastewater-derived nutrient sources. Consequently, this combination is promising for developing biorefinery and biofuel applications in the pulp and paper industry.