Microalgae and Wastewater Treatment: Advantages and Disadvantages

Wastewater generation has concomitantly increased with the growth of world human population in the last century. The uncontrolled discharge of wastewater may result in serious social, environmental and health problems. At the same time, the use of microalgal-based systems has been widely studied for a variety of residual effluents treatment since the early 1950s. In this context, different technologies have been developed, and new strategies to cope with specific needs have been investigated worldwide. There are several advantages of microalgal-based systems compared to traditional wastewater treatment technologies, namely, (1) pollutants and pathogen decrease, (2) nutrient recovery in the form of valuable biomass, (3) energy savings and (4) CO2 emissions reduction. In spite of all these advantages, there are still many challenges to overcome before attaining the real implementation of this technology. Those challenges include (1) land requirement, (2) effect of wastewater characteristics, (3) environmental and operational condition influence and (4) biomass harvesting and valorization. This chapter will explore and discuss the main advantages and limitations of using this green technology for wastewater treatment based on our expertise and the latest insights on this topic.