Cellulose recovery from municipal wastewater and its valorisation for a circular economy: A case study of an Australian WWTP

• Australian case study on cellulose recovery from wastewater and its valorisation • Screenings contained over 80% cellulose after sieving primary wastewater • Cellulose removal achieved ∼50% TSS and ∼27% COD reduction • Recycled cellulose and nanofibres exhibited high purity characteristics • Demonstrated WWTP potential as bio-refineries for a circular economy Cellulose recovery has emerged as a promising pathway for sustainable wastewater treatment and the transition towards a circular economy. This study experimentally validated cellulose recovery and valorisation at a medium-scale Australian wastewater treatment plant (WWTP). Approximately 50% of total suspended solids and 27% of chemical oxygen demand were removed from the sewage using a 0.355 mm sieve device, with the recovered screenings enriched to over 80% cellulose (dry mass). The recovered materials were further processed into recovered cellulose and cellulose nanofibrils (CNFs). Characterisation confirmed that the cellulose backbone was preserved, with thermal stability comparable to commercial microcrystalline cellulose and CNFs derived from clean pulp. Experimental and published data indicate that implementing this approach at the WWTP could substantially reduce sludge production, aeration energy, and carbon emissions. The findings demonstrate efficient cellulose recovery and validate the recovered cellulose as a reliable feedstock, positioning WWTPs as potential bio-refineries for renewable material production.