Impact of Water Hyacinth ( Eicchornia crassipes ) as a Feedstock for Biogas Production

Abstract

Globally, biogas is considered as a clean and renewable form of energy that could replace the increasing non-renewable energy usages. In view of this, there is an increasing demand for energy crops and animal manures for an eco-friendly energy source to supplement fossil fuel, aid in heat production and for electricity generation. Biochemical methane potential test is generally used to determine the possible methane that can be obtained from feedstocks. This study, however, aims at optimizing the anaerobic digestion of water hyacinth, Eicchornia crassipes with cattle manure in a biochemical methane potential test, controlled at mesophilic temperature (37 ± 1). Biodigester A (with the least methane yield) contained only the inoculum and was used as the blank, biodigester B (1:1 feedstock to inoculum ratio) and biodigester C (highest methane yield at 1:4 feedstocks to inoculum ratio) contained both the inoculum and the feedstock at different loading rates. Methane production was measured for a retention period of 30 days using three 1000ml Schott bottles as biodigesters in batch mode. Eicchornia crassipes was characterized in the batch reactor to enable the inoculum activity and the biogas volume reported during the 30 days. Qualitatively, the highest methane composition was found to be 60% whiles quantitatively, the cumulative average methane yield was 77ml throughout the study. The higher yield of methane observed in this study gives an indication of lower cost in the purification of the carbon dioxide from the produced biogas to be used in biofuels for electricity generation and also for combined heat and power production. Therefore, water hyacinth has the potential to produce biomethane which can be used to ease the dependency on fossil fuel derived energy and as an alternative energy source for combined heat and energy which is eco-friendly.