Investigation on biogas production from coconut water using a full-scale upflow anaerobic hybrid bioreactor

The water from coconuts (Cocos nucifera L.) is used to make sugar and its derivatives. Many agro-industries, like Kopra, release the coconut water as effluent into waterways. In this experiment, performance was evaluated at different HRTs of 15, 12, 10, 8, and 6 days using a UAHBR reactor. The maximum daily and volumetric biogas output during a 6-day HRT were 114 L and 877 L.m−3, respectively. The maximum specific biogas production and productivity for the 15 days of HRT were 225.73 L.kg−1 TSadded and 8.7 L.L−1. The performance of the full-scale UAHBR was assessed following 16.67 and 15 days of operation at various HRTs. The maximal specific biogas production and productivity during the 15-day HRT were 13.50 L.L−1 and 354.31 L.kg−1 TSadded, respectively. The TS reduction was between 79.35 and 81.40 during the 15 days of HRT. These results show that residual coconut water can be used to create biogas for a circular economy in business and a sustainable environment.