Biogas Production from Invasive Aquatic Weeds (Water Hyacinth and Water Lettuce) from the Volta River Estuary, Ada-Ghana

Abstract

Water Hyacinth, E. crassipes, and Water Lettuce, Pistia stratiotes are invasive water weeds that thrive in freshwater bodies and estuaries. These weeds have high cellulose and hemicellulose concentrations, highlighting their potential for generating biogas and other bioenergy sources. Since these invasive aquatic weeds could potentially have a positive economic impact, this study aimed to investigate their possible economic benefits and assess the possibility for biogas production from their biomass. For this investigation, the Volta River Estuary near Ada was chosen as the study area. At Ada, boats were used to harvest weeds from the Volta River Estuary. They were placed in an ice chest and taken to the laboratory. The experiment was performed by first pre-treating the two weeds. The pre-treatment involved using mortar and pestle to pound the weeds to create a larger surface area for microbial activity on the weeds. Pre-treated Water hyacinth/Water lettuce plus cow dung were continually fed into an anaerobic digester for 45days and allowed to generate biogas. Factors such as pH and temperature were closely monitored during the digestion period. The Chemical and elemental composition of the two weeds were also determined. Descriptive and inferential statistics were used to describe the variations in the parameters. At the end of the study, Eichhornia crassipes and Pistia stratiotes exhibited the potency to be used as feedstocks for biogas production. Based on the Analysis of Variance and Z-Tests findings, it was realized that the means of the biogas yield of the two weeds differ significantly. Consequently, water hyacinth has been identified as the perfect weed suitable for the production of large-scale biogas.