Sunday, April 29, 2007

Hydrodynamic characterization of a column type prototype bioreactor

Melvin García-Nazariega1, Teodoro Espinosa-Solares1, Marcos Morales-Contreras2, Fabián Robles-Martínez2, and Consuelo Lobato-Calleros1. (1) Ingeniería Agroindustrial, Universidad Autónoma Chapingo, Carretera Mexico-Texcoco,, Km 38.5, Chapingo, 56230, Mexico, (2) Bioprocesos, Unidad Profesional Interdisciplinaria de Biotecnología del IPN, Av. Acueducto s/n, Barrio la Laguna-Ticoman, Mexico City, 07340, Mexico

Agro-food industries produce a large amount of residuals from their processes, being organic matter the most of them. Through the possible solutions for the treatment of those residuals is the anaerobic digestion, using bioreactors for this purpose. An 18 L novel bioreactor for treating waste water was designed based on pneumatic agitation and semispherical baffles. Flow patterns were visualized using the particle tracer technique, circulation times were measured with the particle tracer and the thermal technique; while mixing times were measured using the thermal technique. Newtonian fluid and two Non-Newtonian fluids were used to simulate the operational conditions. The results showed that the change form Newtonian to non-Newtonian properties reduce the mixed zones, increase the circulation and mixing times. Circulation time using the thermal and the tracer particle method had good agreement. A correlation was found between Froude number (Fr) and the dimensionless mixing time (Өm).