Hydrothermal treatment of plastic waste within a circular economy perspective

Concentration of plastic waste is increasing rapidly in the environment posing serious threats to the lives of all species and emerging ecological instability. Increased consumption of plastic goods, the ability to generate high revenue, and less availability of recycling methods shift the focus on the plastic economy. Various strategies have been employed to mitigate this problem but the conversion of plastic waste to energy-rich fuels is more promising and can be more supportive in the future. Mechanical recycling, incineration, pyrolysis, and hydrothermal treatment are the conversion technologies that have been adopted over the passage of time for energy production applications. For the success of all these waste to energy technologies, they need to reduce their capital costs and generate some additional revenues may be in form of fuels or other by-products. Thus the circular economy approach can be used to solve the increasing waste problem and to moderate the increasing energy demand by the conversation of waste into energy. In this article details, discussion has been carried out on all the waste to energy conversion technologies in the context of circular economy perspective by highlighting the important research gaps to solidify the new directions for future studies.