Lab-scale anaerobic digestion of cassava peels: A first step of energy recovery from cassava waste and water hyacinth


Cassava processing in Republic of Benin, which is used to produce different food products, generates a large amount of polluting organic matter into the environment in the form of peels and wastewater. Besides, water hyacinth a rich nitrogen plant invades Benin water streams leading in aquatic ecosystem asphyxia and blocks the navigation. Both cassava waste and water hyacinth show a high biodegradable content enable to be treated by anaerobic digestion technology. According to the literature, the main challenge in cassava waste anaerobic digestion is early inhibition caused by a rapid acidification due to low nitrogen and high biodegradable sugars content. This study focused on the theoretical and biochemical methanogenic potential determination which is an essential step of recovery energy on large scale of both substrates through anaerobic digestion. Stoichiometric methanogenic potentials of cassava waste are close to the values obtained experimentally. However, it was necessary to treat cassava peels with«akanwu» potash and phosphate buffer pH 7.2 to cassava peels (CP) vial to reach the maximum methane yield. Average cumulative methane yield was 368?mL/gVS; 309 mL /gVS and 178 mL /gVS respectively for cassava wastewater (CWW), cassava peels and water hyacinth (WH). Co-digestion of cassava peels with water hyacinth yielded on average 211?mL/gVS of methane. Despite methane yield of co-digestion was lower than the summative of methane yield of each substrate, the process has removed the chemicals products then improved cassava peels treatment. In addition, the methane yield of water hyacinth increased by 10% when co-digested with cassava peels.

Authors: Ahou YS, Bautista Angeli JR, Awad S, Baba-Moussa L, Andres Y.
; Full Source: Environmental Technology. 2019 Sep 20:1-22. doi: 10.1080/09593330.2019.1670266. [Epub ahead of print]