Wasterwater Preteatment with membranes . Pretatamiento de agua residual urbana mediante filtración con membranas

Abstract

Direct membrane filtration of municipal wastewater from the city of Valladolid, Spain using an ultrafiltration membrane was investigated to concentrate the particulate organic matter. This is a physical process at 13-15 ºC that can be used as pretreatment for wastewater. This pretreatment together with an anaerobic process at low temperature could replace the active sludge process. In the new scheme proposed the permeated from the membrane would go to a posterior anaerobic treatment (UASB reactor operating under psychrophilic conditions) and the accumulated solids would be treated by an anaerobic digestion at 35ºC (mesophilic). The aim of this study was to evaluate the membrane filtration conditions. On the lower region of the membrane module results of TCOD 81.842gO2/L, 45.18gTS/L and 38.03gVS/L were reached. The permeate flux was 13.44 L/m2h with a filtration cycle of 7.75min (backwash time (15s), relaxation (5s), filtration (7.5min.) and a pausing time (5s), and a velocity of the gas 54.57m/h. The range for filtration TMP was 471 to 709.33 mbar. The average removal rate for TSS and VSS was 96.26% and 96.20% respectively and the specific methane production of the accumulated VS was 246.37 mLCh4/gSVfed and the TCOD average removal rate was 46.10%. Keywords: Direct Membrane Filtration, Recovery of Organic Matter, Municipal Wastewater, Accumulated Solids, and Anaerobic digestion 35 ºC. Filtración directa con membranas de agua residual urbanaa de Valladolid, España mediante ultrafiltración para concentrar la mateia orgánica particulada. Es un proceso físico entre 13-15 º C que puede ser utilizado como un pretratamiento de agua residual. Este pretratamiento junto con un proceso anaróbico a baja temperatura podría reemplazar el proceso convencional de fangos activos. En el esquema propuesto, el permeado de la membrana se trataría bajo una digestión anaeróbia a 35ºC (mesofílica)