3.3 Composition of water hyacinth hydrolysate (sludge) The water hyacinth hydrolysate (sludge) pretreated with sulfuric acid concentrations of 0.0, 2.0, 2.5 and 3.0 % (v/v) were tested for chemical composition (cellulose, hemicellulose and lignin) by the method of Goering and Van Soest