Mechanism and challenges behind algae as a wastewater treatment choice for bioenergy production and beyond

• Published in: Fuel (Guildford) 2021-02, Vol.285, p.119093, Article 119093
• Main Authors: Yadav, Geetanjali, Shanmugam, Sabarathinam, Sivaramakrishnan, Ramachandran, Kumar, Deepak, Mathimani, Thangavel, Brindhadevi, Kathirvel, Pugazhendhi, Arivalagan, Rajendran, Karthik
• Format: Article
• Language: English
• Subjects: CO2 fixation; Heterotrophic cultivation; Microalgae; Two-stage cultivation; Wastewater treatment
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2020.119093

[Display omitted] •Feasibility of microalgae-based wastewater treatment technology was reviewed.•Biochemical composition of microalgae used in wastewater treatment was presented.•Mechanisms of removal of nutrients and organics by microalgae were evaluated.•Recent advances in algae cultivation systems for wastewater treatment was discussed.•Challenges, limitations and opportunities existing in this technology were addressed. Conventional wastewater (WW) treatment uses activated sludge process, which is accepted worldwide. However, the sustainability of such a process is questioned in terms of emissions, energy savings, and economic benefits. Microalgae based WW treatment has been proposed as a viable alternative to conventional WW treatment. In microalgae treatment, WW including organics and nutrients gets converted to algae, while reclaimed water is discharged back to the environment. Microalgae could be used as a precursor for biochemicals, biofuels or other bio-based products. There are different technologies within microalgae-based WW treatment including adsorption, accumulation, and immobilization of algae. This review attempts to understand the mechanisms of these technologies on how nutrients and organics are removed from WW. Though it is a viable alternative, there are several challenges and limitation that exist in this technology which needs to be addressed to have a commercial perspective. Algae based WW treatment is analysed for its limitation and has been reported here. Beyond WW treatment, this method should also be looked as an emission reduction strategy through CO2 fixation.