Value-Added Products Derived from Waste Activated Sludge: A Biorefinery Perspective

Abstract

Substantial research has been carried out on sustainable waste activated sludge (WAS) management in the last decade. In addition to the traditional approach to reduce its production volume, considering WAS as a feedstock to produce bio-products such as amino acids, proteins, short chain fatty acids, enzymes, bio-pesticides, bio-plastics, bio-flocculants and bio-surfactants represents a key component in the transformation of wastewater treatment plants into biorefineries. The quality of these bio-products is a key factor with respect to the feasibility of non-conventional WAS-based production processes. This review provides a critical assessment of the production process routes of a wide range of value-added products from WAS, their current limitations, and recommendations for future research to help promote more sustainable management of this under-utilised and ever-growing waste stream.

Keywords

• bioplastics
• biopolymers
• biosolids
• biorefinery
• resource recovery
• waste activated sludge