This paper reports on improvements to aggregation kinetics of colloidal particles in municipal water treatment by the use of curved fluidic structures, resulting in up to 50% reduction in coagulant dosage. A novel high throughput, purely fluidic, continuous flow, membrane-less, size selective method for particulate separation has been recently reported where centrifugal force created in spiral flow channels generate transverse hydrodynamic forces to separate micron-sized neutrally buoyant particles which are further focused and diverted for extraction1,2. Together, the improved aggregation and particulate separation offer a potentially transformative approach3 to the conventional practice of water treatment. The combined effects of the spiral mixers with improved agglomeration to generate denser and uniformly sized pin floc, and spiral separators for in-line clarification presents an opportunity to eliminate flocculation and sedimentation steps, resulting in potentially significant savings in reduced land use, chemical cost, operational overhead, and faster processing time from raw to finished water. This technology improvement is also directly relevant to other water applications, including: industrial water purification, waste water reclaim, power plant cooling tower, pre-treatment for RO, and almost any instance where reduction of TSS loading reduces clogging and extends the time between cleaning for many MF and UF filtration membranes.
Lean, M.; Kole, A.; Chang, N. E.; Voelkel, A. R.; Seo, J.; Hsieh, H. B. Curved fluidic structures to improve aggregation kinetics in municipal water treatment. AWWA Water Quality Technology Conference; 2008 November 18; Cincinnati, OH.