Upcycling spent activated carbon from wastewater treatment systems: Industrial and ecological options

Spent activated carbon (SAC) generated from wastewater treatment processes is an environmental menace if not handled appropriately following international regulations. With limitations in its disposal options, other routes have been devised to regenerate and recycle it for the initial primary purposes. However, the economic and technological aspects are still a hindrance to reapplying SAC in the initial processes due to the degradation of its key properties during the regeneration processes. Upcycling, a relatively newer term in industrial processes involving degradable inputs such as activated carbon involves repurposing a used material for other applications with more value to it. This work presents ecological and industrial routes that are potentially feasible for upcycling SAC generated from wastewater treatment systems. Instead of disposing of spent activated carbon as waste, upcycling aims to extract additional value from the material. The process parametric conditions for the various upcycling options are elucidated whereas critical analyses have been entailed for each option regarding the industrial and ecological practicality despite some laboratory-scale green-flagging as per scholarly publications.