Valorization of paper and pulp waste: Opportunities and prospects of biorefinery

The paper and pulp industry (PPI) is regarded as one of the most polluted, as it produces high quantities of solid and liquid discharge. On average, in a developed country, up to 10 million tons of waste is generated each year and considerable amounts of capital and other resources goes toward its treatment. The discharge from PPIs mainly constitutes solid and liquid waste with high organic content. This discharge is a potential feedstock containing a high percentage of lignin, cellulose, and hemicellulose, which can be used as a valuable raw material for the production of bioenergy, platform chemicals, and biofuels. At present, most of this waste is recycled using a conventional approach, through biological and chemical processes, incurring high costs and low returns. Therefore, strategies relying on any one of the conventional treatment technologies do not lead to optimal utilization of the valuable resources in the waste. Instead, cascading approaches such as coupling the generation of conventional bioenergy and high-value bioproducts within a biorefinery context could address this challenge. Therefore, this chapter initially provides a detailed account of the availability of paper and pulp waste and pretreatment methods. Various high-value bioproducts that can be produced in a biorefinery approach are discussed in order to pinpoint the most recent trends and future directions in research and development. It also focuses on technologies that have moved beyond the laboratory phase, identifies the problems, and summarizes the main interventions that can help overcome these issues. The chapter thus provides systemic insight into developing efficient, economically feasible, and sustainable biorefineries that could meet the technical and market requirements and improve the valorization of paper and pulp waste.