Pre-treatment techniques used for anaerobic digestion of algae

In order to improve the biogas production, pre-treatment techniques have been investigated to disrupt the structure of algae increasing the availability of substrates. In this paper, a review of these pre-treatment methods is presented. Pre-treatment methods are categorised into mechanical, ultrasound and micro-wave, thermal, chemical, biological and combined groups. The effect of the application of each of the studied techniques on the biogas yield and the energy balance is discussed. A comparison of the used techniques is carried out, and discussed.