Lawrence Berkeley National Laboratory

Postconsumer absorbent hygiene products (AHPs), one of the most intractable municipal solid waste (MSW) streams, are generally subjected to landfills, causing urban waste management difficulties and environmental pollution. This study investigated the viability of recycling the cellulose component from postconsumer AHPs, demonstrated the fermentability of obtained cellulosic sugars for bioethanol production, and evaluated the technical feasibility of the process through scale-up. A set of integrated unit operations was developed to effectively upcycle the recovered AHPs into bioproducts. The processes were further optimized and scaled up 50-fold. Up to 83.5% glucose and 46.0% xylose yields were achieved during enzymatic saccharification. The sugars were readily fermentable through separate hydrolysis and fermentation (SHF) as well as simultaneous saccharification and fermentation (SSF) with maximum 89.9% ethanol theoretical yield.