Integrated digital, biological, and human capital innovations for circular and sustainable waste management: a critical review

Abstract Global waste management faces increasingly complex socio-technical challenges that cannot be solved by technology alone. This PRISMA-guided review synthesizes 80 peer-reviewed studies published 2020–2025 via structured searches of Scopus and Web of Science, concentrating on three integration pathways: (i) AI/IoT-enabled collection and sorting; (ii) scalable biological/enzymatic treatments (anaerobic digestion/composting; PET enzymatic depolymerization); and (iii) human-capital and policy enablers in LMIC and post-conflict contexts. Across the literature, smart and biological systems improve material recovery and environmental performance in well-resourced settings, yet scalability in LMICs is constrained by weak institutions, skills gaps, and fragmented infrastructure. Iraq is used as an illustrative post-conflict case, confirming a broader pattern in which technological potential outpaces institutional readiness. The review advances an integrative socio-technical lens and offers a feasibility-oriented appraisal of performance and deployment trade-offs, emphasizing that technology and human capital must advance in tandem. It also acknowledges global structural factors—unequal access to finance, distortions in material markets, and cross-border e-waste flows—that condition adoption. We conclude with near-term priorities: appropriate-technology pilots, measurable reskilling programs, and financing models that de-risk municipal adoption and support context-sensitive circular transitions.