The wastewater using in technologies of bio-oil production from microalgae: CO₂ capture and storage

Abstract

Bioenergy remains the largest renewable energy industry. At the same time, microalgae (MA) are a promising object of research among other types of biomass and the scale of microalgae using for energy purposes is increasing. Industrial cultivation of microalgae opens up great opportunities for CO2 utilization and wastewater treatment from organic and mineral pollutants, and also significantly reduces the load on fresh water supplies. To reduce the cost of biofuels, optimization of a whole number of technological stages, including the cultivation of MA, is necessary. The paper presents the results of developing methods for cultivating MA to optimize their growth and absorption of nutrients from wastewater. A culture of microalgae/cyanobacteria Arthrospira platensis rsemsu P (Bios) (collection of RSE Laboratory at Lomonosov MSU) which grew well in wastewater was experimentally selected. The results of the wet MA biomass conversion into bio-oil by hydrothermal liquefaction (HTL) technology with the associated production of biochar are presented. Biochar producing can be considered as a method for capturing and storing carbon.

Effects of Light Intensity on the Growth and Biochemical Composition in Various Microalgae Grown at High CO2 Concentrations

“…The advantages of microalgae as photosynthetic agents of carbon conversion have been repeatedly discussed. It is worth emphasizing the most important of them: (1) the cultivation of microalgae does not require arable land, unlike terrestrial crops, and the use of wastewater as a nutrient medium reduces the consumption of water and inorganic components of nutrient media [6][7][8]; (2) microalgae can synthesize valuable metabolites, vitamins, and various organic compounds in commercially significant volumes [9,10]. For effective CO 2 absorption, it is necessary to select the most productive strains of microalgae tolerant to high concentrations of CO 2 and flue gases [11][12][13], as well as to search for optimal cultivation conditions to obtain maximum biomass productivity.…”

The Influence of Elevated CO2 Concentrations on the Growth of Various Microalgae Strains

“…Due to the simple structure and affordable nutrition, microalgae have theoretically higher photosynthesis efficiency compared to terrestrial plants [6,7]. Algae cultivation does not require arable land, and using wastewater as a nutrient medium will reduce the need for water by 90% and fully satisfy the need for nutrients [8][9][10][11]. On the other hand, the observed active flowering of cyanobacteria in the natural environment over recent decades, associated with an increased CO 2 content and temperature, requires additional studies, since this can bring substantial impacts on water quality and ecosystem function as whole [12,13].…”