Microalgae Harvesting and Dewatering Methods

Preparation of Microalgae to produce biofuel involves three stages: cultivation, dewatering and oil extraction. Efficient dewatering of microalgae is the main challenge in industrial scale. The high cost of microalgae production is due to the lack of suitable method for harvesting. This paper aims to describe and compare the different microalgae harvesting methods. As a matter of fact, these methods are divided into three categories which are described as chemical, mechanical and electrical methods. The chemical method consists of coagulation and flocculation steps but none of these steps are economical. Centrifuging is a common method for mechanical harvesting. Relatively this method has high efficiency but it is not cost beneficial because of high energy consumption. Among the electrical methods, electrocoagulation is a new method for microalgae harvesting which offers higher efficiency and demands lower energy than other methods.