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Industrial production of biogas offers a way to manage distillery leachate. The waste is usually subjected to anaerobic digestion for producing biogas. However, the effluent from anaerobic processes has high chemical oxygen demand (COD) and is harmful to the environment. An effective method of lowering COD is ozonation. Effluent from biogas plants after ozonation has the potential for use in breeding grounds for plants of the Lemnaceae family. Thus, they can provide a valuable additional source of biomass for the production of bioethanol. Lemna minor L. and Spirodela polyrhiza cultures were grown in media with the addition of 2.5% PFE, which had been treated by ozonation for between 6 and 50 min. Using ozonated effluent was an effective cultivation technique in all variants. The analyzed parameters were plant growth, chlorophyll index, fresh plant weight and photosynthetic traits (net photosynthesis, stomatal conductance, transpiration and concentration of intercellular CO2). The best growth of Lemna minor L. was observed in the media with PFE treated for 12 min. Similar effects were obtained for S. polyrhiza, with ozone treatment for 12 and 25 min. The results show the potential of using ozone-treated post-fermentation leachate as a supplement in culture media. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]