Integration of biological waste conversion and wastewater treatment plants by microalgae cultivation

In this study, growth performance and lipid content of two microalgae species Neochloris oleoabundans and Chlorella vulgaris are monitored by using three different types of sludge waste feedstocks obtained from the water treatment plants located in Bedonia, Borgotaro and Fornovo (Montagna2000 Spa, Province of Parma, Italy). The sludge waste is optimized in order to achieve microalgal growth media and dispose of the sewage sludge produced at the wastewater treatment facilities. Both photoautotrophic and heterotrophic growth conditions are applied to the microalgal cultivations. The growth parameters of microalgae strains such as cell concentration, growth rate, optical density, cell biovolume, photosynthetic pigments and lipid contents are monitored. The amounts of total dried lipid biomass, obtained by the biological conversion of the wet sludge waste, are determined. Lipid production of microalgal cells grown in the medium optimized from sludge waste from the Fornovo site provides the highest amount of microalgal lipid content for N. oleoabundans and C. vulgaris photoautotrophic cultivations, while sludge waste from the Bedonia site provides for N. oleoabundans heterotrophic cultivation.