Here, we present real-space studies of Brownian hard sphere transport though externally defined potential energy
landscapes. Specifically, we examine how colloidal particles are re-routed as moderately dense suspensions pass
through optical lattices, concentrating our attention upon the degree of sorting that occurs in multi-species flows.
While methodologies reported elsewhere for microfluidic sorting of colloidal or biological matter employ active
intervention to identify and selectively re-route particles one-by-one, the sorting described here is passive, with
intrinsically parallel processing. In fact, the densities of co-flowing species examined here are sufficient to allow for
significant many-body effects, which generally reduce the efficiencies of re-routing and sorting. We have studied
four classes of transport phenomena, involving colloidal traffic within, respectively, a static lattice with a DC fluid
flow, a continuously translating lattice with a DC fluid flow, a flashing lattice with AC fluid flow, and a flashing
lattice with combined AC and DC fluid flow. We find that continuous lattice translation helps to reduce nearest
neighbor particle distances, providing promise for efficiency improvements in future high throughput applications.