Effect of microalgae biomass cultivated under elevated CO2 concentrations on the process of anaerobic digestion of organo-containing waste

This article presents the results of an experimental study on the anaerobic digestion of Chlorella kessleri microalgae biomass, preliminarily cultivated under elevated CO₂ concentrations. The digestion process was carried out with the addition of food waste and cow manure as an inoculum.

The aim of the work is to determine the optimal ratio of the components of the fermentation mixture (microalgae — food waste — inoculant) for organic carbon for maximum biogas yield and its energy potential (in terms of methane content in biogas).

It was found that the best results (1,018 liters of biogas and 67.3% methane) were achieved with a ratio of 1.0 g — 3.2 g — 4.0 g, while the maximum proportion of methane (67.8%) was recorded with the addition of 1.2 g of microalgae.

The obtained results support the recommendation to use Chlorella kessleri biomass, previously cultivated under elevated CO₂ conditions, as an additive in co-anaerobic digestion with food waste and inoculum. This approach is proposed as an energy-efficient, environmentally friendly, and economically viable method to enhance the biogas potential of feedstock mixtures. 

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