Novel stacked modular open raceway ponds for microalgae biomass cultivation in biogas plants: Preliminary design and modelling

Abstract

Microalgae hold great potential as a source for renewable energy due to their high photosynthetic efficiency, high growth rates and independence from fertile agricultural lands. However, large-scale cultivation systems of microalgae biomass are still not economically viable mainly due to the difficulties with maintaining optimum growth conditions of microalgae in open pond systems and high costs of biomass cultivation and harvesting. Here we propose the Novel Stacked Modular Open Raceway Ponds (SMORPs) system for microalgae biomass cultivation to be integrated in biogas production plant. The proposed technological solution will eliminate the drawbacks of current microalgae cultivation technologies, mainly, will reduce the land use, improve lighting conditions and reduce the cost of cultivation as a result of the application of waste products from biogas production, i.e. anaerobic digestion effluent and flue gas. In this study we propose the initial design of the SMORP concept and a microalgae biomass kinetic model as a simple approach to screen microalgae strains potentially applicable for large-scale ponds. The developed tool is also useful to evaluate the potential benefit of additional artificial LED light sources and to assess the maximum biomass growth rate with minimal light intensity.