Development of a self-reinforcing nanocellulose-based Rhizopus oryzae living hydrogel for enhanced treatment of ultra-high COD pulp and paper industry wastewater

Urbanization and industrialization have led to increased wastewater production, with the pulp and paper industry being a major contributor due to its high organic load and toxic compounds. Conventional treatment methods, like chemical and physical processes, often fail to remove these pollutants sufficiently and can cause secondary contamination. Biological wastewater treatment, particularly the activated sludge process, shows promise in addressing these challenges. Ongoing research explores new materials such as nanobiomaterials and living hydrogels embedded with microorganisms. In this study, a nanocellulose-based Rhizopus oryzae living hydrogel was developed for wood cooking wastewater treatment, reducing COD by 64.3 % (from 26388 mg/L to 9432 mg/L) and BOD 5 by 54.9 % (from 10602 mg/L to 4780 mg/L). This hydrogel outperformed commercial-activated sludge and enhanced its mechanical properties while also providing UV shielding by adsorbing lignin from the wastewater. • The living hydrogel was constructed by Rhizopus oryzae and TOCN. • Living hydrogels can effectively reduce ultra-high concentrations of BOD 5 and COD. • Living hydrogels can be self-strengthened and UV shielded by utilizing wastewater.