Making Cardboard and Paper Recycling More Sustainable: Recycled Paper Sludge For Energy Production and Water-Treatment Applications

Rising socioeconomic level and increasing popularity of e-commerce have dramatically increased the use of cardboard packaging materials, and consequent related recycling and wastes. Large amounts of sludge (up to 40% of input mass) is formed through the recycling process, with sludge solids that are very rich in cellulose fibers (similar to 75% w/w). To date this sludge is mostly disposed in landfills, resulting in added economic and environmental costs to the recycling process. Short ozonation pretreatment of RPS resulted in enzymatic release of similar to 34% of the cellulosic fraction of the sludge as sugar, and fermentation of these sugars by yeasts resulted in production of similar to 15 g/L ethanol. The solid remnants, were used as a bio-sorbent, efficiently removing dyes from textile wastewater. Recycled paper sludge waste was thus a good source for both energy and water-treatment applications, increasing sustainability and circular economy in the paper and cardboard recycling industry.

Automated summary

The increasing use of cardboard packaging materials due to rising socioeconomic levels and the popularity of e-commerce has led to a significant increase in recycling and waste management. The sludge produced during the recycling process contains a high percentage of cellulose fibers, but is currently disposed in landfills, adding to the economic and environmental costs of recycling. However, innovative approaches such as short ozonation pretreatment have shown potential in converting the cellulosic fraction of the sludge into valuable products like sugar and ethanol, as well as using solid remnants for wastewater treatment, thereby promoting sustainability and circular economy in the paper and cardboard recycling industry.