"An effective returns management process is required to efficiently collect used and recyclable materials for subsequent lifecycles. Unfortunately, the economics of future material flows will be highly inconsistent with those found in the forward deployment of product. Whereas full pallet-loads of homogeneous (similar) products are distributed in the forward channel, the reverse channel consists of odds and ends that are usually poorly contained and lack the original packaging. This will increase as customer segments diversify around the globe….
"Given their strategic importance, wholly separate channels are often devised for returned goods. Specialized service providers [3PLs] are often called on to support the collection and flow of returned goods."
-- from "Global Macrotrends and their Impact on Supply Chain Management" Chad W. Autry, Thomas J. Goldsby and John E. Bell (FT Press, 2013)