Water hyacinth biomass: chemical and thermal pre-treatment for energetic utilization in anaerobic digestion process.

Abstract The water hyacinth (Eichhornia crassipes) is a floating aquatic plant belonging to the Pontederiaceae family. This plant, native to South America, grows on the surface of lakes, rivers and canals in tropical and sub-tropical areas. Because of its human transport in other tropical climate areas and its high grow rate, the water hyacinth is considered one of the prominent invading macrophytes in eutrophic water basins; the quality of water in those regions have been negatively affected. The water hyacinth is characterized by a high content of lignocellulosic biomass, with a 10% average content of lignin, useful in both thermochemical and biochemical processes. The anaerobic digestion process should be considered as a very attractive solution to produce biogas. This kind of biomass needs to be chemically and thermally treated before being directly involved into the anaerobic digestion reaction. This work aims to give a detailed analysis of water hyacinth biomass energy properties in terms of its use in anaerobic digestion processes, before and after targeted treatments, highlighting any improvements that should be made to the procedures by literature. Related process parameters are also investigated. The conducted experimental campaign shows how the thermal pre-treatment at low temperatures increases the volatile solids content from 57% to 74% (w/w), decreasing the ash content. [ABSTRACT FROM AUTHOR]