Anaerobic Digestion Effluents (ADEs) Treatment Coupling with Chlorella sp. Microalgae Production.

  Nutrient removal effectiveness from anaerobic digestion effluents (ADEs) by Chlorella sp. cultivation and microalgae biomass productivity were evaluated in this study. The results showed that the highest Chlorella sp. biomass productivities of 386.5 ± 24.1 mg dry weight/L•d and 338.3 ± 11.0 mg dry weight/L•d were respectively obtained with the anaerobically digested effluent of municipal wastewater sludge and effluent from a fermentation tank treating dairy wastewater. Lower (p < 0.05) microalgal growth was achieved with anaerobically digested effluents of maize silage and swine slurry and cattle manure. The increase of the initial ammonia nitrogen concentration in ADEs to the level of 160 mg/L did not encourage Chlorella sp. productivity because of phosphorus limitation. The removal efficiencies of ammonia nitrogen, total nitrogen, total phosphorus, and chemical oxygen demand (COD) reached 99.7%, 98.6%, 88.2%, and 58.7%, respectively, depending on the source of ADE, but not on the initial ammonia nitrogen concentrations.