An integrated approach to energy production and nutrient recovery through anaerobic digestion of Vetiveria zizanoides

This paper reports on experimental results used to verify the applicability of Vetiveria zizanoides (VZ) as a virtuous energetic crop. VZ produces biogas through its anaerobic digestion, and its nutrient content can be recovered through reuse, after digestion, as an agricultural amendment. Biomethanation tests were conducted with fresh and pretreated VZ, and the results of these tests were compared with those from the anaerobic degradation of common garden grass. Specific methane production was found to be around 650 Nm3 per ton of total organic carbon (TOC) for Vetiveria zizanoides, and around 510 Nm3 per ton of TOC for common grass, with no significant improvement after thermal pretreatment. Germination tests conducted with the digested VZ showed that the produced digestate fulfills the requirements of a fertilizer.