Sustainable management of tea wastes: resource recovery and conversion techniques

As the demand for tea (Camellia sinensis) has grown across the world, the amount of biomass waste that has been produced during the harvesting process has also increased. Tea consumption was estimated at about 6.3 million tonnes in 2020 and is anticipated to reach 7.4 million tonnes by 2025. The generation of tea waste (TW) after use has also increased concurrently with rising tea consumption. TW includes clipped stems, wasted tea leaves, and buds. Many TW-derived products have proven benefits in various applications, including energy generation, energy storage, wastewater treatment, and pharmaceuticals. TW is widely used in environmental and energy-related applications. Energy recovery from low- and medium-calorific value fuels may be accomplished in a highly efficient manner using pyrolysis, anaerobic digestion, and gasification. TW-made biochar and activated carbon are also promising adsorbents for use in environmental applications. Another area where TW shows promise is in the synthesis of phytochemicals. This review offers an overview of the conversion procedures for TW into value-added products. Further, the improvements in their applications for energy generation, energy storage, removal of different contaminants, and extraction of phytochemicals have been reviewed. A comprehensive assessment of the sustainable use of TWs as environmentally acceptable renewable resources is compiled in this review.

Automated summary

As tea consumption continues to rise, so does the production of biomass waste during the harvesting process. Tea waste (TW), including stems, leaves, and buds, has proven beneficial in energy generation, wastewater treatment, and pharmaceuticals. Conversion procedures such as pyrolysis, anaerobic digestion, and gasification efficiently recover energy from low- and medium-calorific value fuels. TW-derived biochar and activated carbon are promising adsorbents, while TW also shows potential in synthesizing phytochemicals. This review provides an overview of the conversion procedures and applications of TW, offering a comprehensive assessment of its sustainable use as a renewable resource.