Water Resources Research Act Program

Details for Project ID 2019OH214B

Capillary trapping of buoyant particles by cylindrical collectors and its application in transport of floating fertilizers in overland flow

Institute: Ohio
Year Established: 2019 Start Date: 2019-06-08 End Date: 2020-06-07
Total Federal Funds: $36,239 Total Non-Federal Funds: $36,239

Principal Investigators: Lei Wu

Project Summary: Minimizing surface water pollution caused by fertilizers requires accurate nutrient transport prediction. In the past, numerous studies have been carried out to describe nutrient transport as solute (for dissolved N and P) or sediment (for particulate P) transport, with limited effort devoted to the transport of controlled release fertilizers (CRFs) in overland flow. Recent studies indicate that some CRFs are buoyant and can float on the surface of water due to capillary attraction attributed to unique polymer coating design properties. For overland flow through vegetative systems, this will result in capillary interception (capture), which can be orders of magnitude more efficient than direct interception. However, this mechanism is not fully described by existing solute transport or sediment transport models. We hypothesize that properties (size, density and contact angle) of CRFs exert primary control on their mobility in overland flow through vegetative systems. We propose to test this hypothesis with two specific objectives. Objective 1: Determine the collision efficiency of buoyant particles by cylindrical collectors in overland flow and develop a new collision efficiency correlation equation to describe this process; and Objective 2: evaluate the new collision efficiency which includes capillary force effects by bench-scale CRFs transport experiments using real vegetation system. Our key innovation includes direct observation and quantification of collision efficiency of buoyant particles captured by model vegetation via trajectory analysis using fluorescent videography and advanced image analysis. We believe that findings from this work will lead to the advancement of multiple theories in contaminant transport, which will provide additional insights and design tools for policy makers and engineers in the areas of water and fertilizer management.