Special D&I Introductory Workshop - Rigoberto Hernandez

The removal of flocs, which are aggregates consisting of solid particulate, from source water is an essential part of the drinking water treatment process. To improve flocculation, salt can be added to increase the solution ionic strength. This creates a charge screening effect, which allows for aggregation of particulate. However, increasing the salt concentration would increase the load on reverse osmosis filters down the line, which is cost prohibitive. The addition of long-chained, charged polymer flocculants makes the flocculation possible without need for excess salt. Flocculation in a treatment tank is subject to a variety of hydrodynamic flow states, and isolating how they affect flocculation is difficult. A Taylor-Couette (TC) cell, which consists of two concentric cylinders where the gap between the cylinders can be filled with fluid, can generate precisely defined flow states at specific rotational speeds. The Dutcher group has built a TC cell with radial injection capabilities from the inner cylinder, therefore flocculation can be captured via image analysis from the start of the process. This TC cell will be used to study how different concentrations of NaCl impact flow dynamics and floc size, growth rate, and configuration.