Integrated Biovalorization of Wastewater for Sustainable Resource Management-Circular Economy

Wastewater is increasingly not just seen as a burden on the environment but also a source of valuable water, nutrients, energy, carbon, and high value bioproducts for recovery. Integrated biovalorization is a promising strategy to develop conventional wastewater treatment systems into resource generating and circular ones. The review critically assesses the emerging biological platforms and integrated process configurations for wastewater biovalorization (WWB) processes such as anaerobic digestion, microbial fermentation, microalgae-bacteria systems, microbial electrochemical technologies, biofertilizer production, and wastewater biorefineries: special focus on conversion of organic carbon to volatile fatty acids, biogas, biohydrogen, biopolymer, protein, enzymes, and other value-added products, recovery of N, P, and water reclamation. The review is focused on the technological performance, resource recovery efficiency, process limitations, environmental sustainability, and commercialization opportunities of the integrated pathways. The potential of membrane technologies, nanomaterials, process intensification, and artificial intelligence and digital monitoring to enhance the process efficiency is also critically discussed. Furthermore, techno-economic analysis, life cycle effects, contaminant risks, regulatory issues, and scale-up issues are determined. Hence, future research directions towards smart, decentralized, low carbon, and commercially viable wastewater biorefineries are suggested.