Abstract

PEREZ MONTIEL, Jhonny Isaac; ALDANA VILLASMIL, Gerardo José  and  ROJANO ALVARADO, Roberto Eliecer. Hydraulic evaluation of an upflow anaerobic sludge blanked reactor (UASB) using an axial dispersion model. Rev. Int. Contam. Ambient [online]. 2016, vol.32, n.3, pp.281-291. ISSN 0188-4999.  https://doi.org/10.20937/RICA.2016.32.03.03.

Hydraulics along with biogeochemical processes have a remarkable value in the efficiency of wastewater treatment systems as upflow anaerobic sludge reactors (UASB). In this study the hydraulic performance was evaluated on a UASB of 518L volume capacity using an axial dispersion model. The reactor was inoculated with 105 L of sludge (20 % v/v) and was fed with a local municipal wastewater flowing at the collector C of the city Ma-racaibo, Venezuela. Assays were carried out using a solution with LiCl (Li+ measured as tracer) incorporated at the influent as instantaneous injection. Samples were collected at the effluent and at a midpoint of the reactor. Different theoretical hydraulic retention times (to) were used such as 10, 8, 5, 4 and 3 h with three inputs aligned in the reactor bottom and to 5 h increasing the inputs in odd numbers up to 15. The number of dispersion obtained at the bed sludge blanket (midpoint) was higher than values obtained at the effluent varying from 1.1842 < d < 1.7550 and 0.2911 < d < 0.7285 respectively. The axial dispersion model with injection and detection in flux (IDF), and injection in flux and detection in resident fluid (IFDRF) showed a good fit from the experimental data of tracer concentration. Two defined areas were found at the reactor, one at the bed and sludge blanket behaving like complete stirred mixing tank and other at the settling basin as dispersed flow tank.

Keywords : tracer; hydraulic retention time; dispersed flow; complete mix; dead zone.