The Environmental Convergence Opportunities in Chemical, Bioengineering, Environmental, and Transport Systems (ECO-CBET)solicitation will support fundamental research activities that confront vexing environmental engineering and sustainability problems bydeveloping foundational knowledge underlying processes and mechanisms such that the design of innovative new materials, processes, andsystems is possible. Projects should be compelling and reflect sustained, coordinated efforts from highly interdisciplinary research teams. Akey objective of the solicitation is to encourage dialogue and tightly integrated collaborations wherein the chemical process systems, transportphenomena, and bioengineering communities engage with environmental engineering and sustainability experts to spark innovation and arriveat unanticipated solutions. Clusters: Chemical Process Systems; Engineering Biology and Health; Environmental Engineering and Sustainability; Transport Phenomena