Biomass Production and Nutrient Removal by Chlorella vulgaris from Anaerobic Digestion Effluents

One of the most important factors determining the profitability of microalgae biomass production is the use of inexpensive and available source of nutrients. The aim of the study was to determine the possibility of using anaerobic digestion effluents (ADE) from the fermentation of distillery stillage, maize silage and bovine slurry as a nutrient in the production of microalgae Chlorella vulgaris biomass. The highest biomass production of 2319 mg TS/dm3 was obtained during the cultivation of microalgae in the medium consisting of the effluents originating from the fermentation with a high share of bovine slurry. Significantly lower Chlorella vulgaris biomass growth was noted during cultivation in the medium composed of effluents obtained after dewatering of anaerobic sludge from the methane fermentation reactor fed with distillery stillage. In these series, an increase of the initial concentration of N-NH4 in the medium to a level of 160 mg/dm3 significantly reduced microalgae growth. The high efficiency of P-PO4 removal from 87–100% was noted. The study proved that anaerobic digestion effluents might be used as a nutrient source for efficient biomass production of Chlorella vulgaris after optimization of ammonium nitrogen dose