Valorization of Municipal Solid Waste in the United States: A Review
Samson Micheal Idoghor
*
Department of Wood Science and Engineering, Oregon State University, Corvallis, OR, USA.
Bright Peter Saah
Department of Civil and Environmental Engineering, Lehigh University, Bethlehem, PA, USA.
Amarachukwu Immaculate Nwandu
Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Nigeria.
Mariam Iyabo Adeoba
Department of Mechanical, Bioresources and Biomedical Engineering, University of South Africa, Pretoria, South Africa.
Linda Egbubine
Josef Korbel School of Global and Public Affairs, University of Denver, Denver, CO, USA.
*Author to whom correspondence should be addressed.
Abstract
Waste valorization has emerged as a critical strategy for transforming municipal solid waste from an environmental burden into a resource, supporting circular economy transitions and sustainability goals. Using a structured search and selection process following PRISMA-ScR guidelines, this scoping review identified and analyzed 127 peer-reviewed articles published between 2015 and 2024 to determine current research trends, valorization technologies, geographic distribution, disciplinary approaches, and associated benefits and challenges. The review revealed that waste valorization research in the United States is dominated by engineering disciplines (74% of lead authors), with strong emphasis on biological conversion technologies, particularly anaerobic digestion and composting for organic waste streams. Geographic imbalances are pronounced, with California, New York, and Massachusetts accounting for 57% of geographically-specific research, while rural areas and less-populated states remain severely underrepresented. Food waste attracted the most research attention (33%), followed by biosolids (22%) and plastics (19%), while textiles and construction debris remain underexplored. Environmental benefits were reported in 89% of articles, yet social dimensions including environmental justice, community acceptance, and workforce development appeared in only 18% of studies. Methodologically, experimental studies and life cycle assessments dominated (64% combined), while implementation-focused research including case studies comprised only 8%. The findings suggest that while waste valorization demonstrates technical feasibility and environmental benefits, critical knowledge gaps persist in social dimensions, geographic representation, economic viability without subsidies, and implementation pathways. Expanding research to include interdisciplinary perspectives, underrepresented regions and waste streams, and systematic examination of implementation barriers is essential for advancing waste valorization from technological promise to widespread, equitable deployment across diverse U.S. contexts.
Keywords: Municipal solid waste, waste valorization, resource recovery, circular economy united states, sustainable materials management