The main composition of the obtained two-step treated WS was moisture 6.5 ± 0.2%, cellulose 88.9 ± 1.2%, lignin 0.9 ± 0.2%, and hemicellulose 2.2 ± 0.3%. The ST hydrolyzate containing 5.5% lignosulfonate could be directly recovered as a cement water reducer.