Eliminación de nitrógeno y contaminación orgánica de agua residual industrial pretratada en lagunas anaeróbicas mediante un biofiltro de arena

Abstract

The present study reports the removal of chemical oxygen demand (COD) and nitrogen from palm oil mill effluent (POME) treated in an anaerobic wastewater treatment plant of a palm oil mill located in the province of Esmeraldas, Ecuador. The treated POME was purified in a laboratory system consisting of a sand biofilter where physical-mechanical (turbidity removal), biological aerobic (organic matter and nitrification removal) and anoxic (denitrification) processes took place. The purification system involved a sand biofilter that discharged into a vessel from where water was recirculated to the biofilter. The removal of organic matter and nitrification was achieved through aeration (8-12 h d −1 ), while denitrification occurred during the anoxic period (12-16 h d −1 ). The system was operated for 294 days and reached 41 to 85 % COD removal and 44 to 87 % ammonium removal. Furthermore, a 12 % reduction in the total inorganic nitrogen concentration was achieved after the anoxic period compared to the aerobic phase.Keywords. industrial wastewater, crude palm oil, sand biofilter, nitrification, denitrification, COD removal, ammonium removal, aerobic, anoxic. ResumenLa presente investigación trata sobre la eliminación de carga orgánica y nitrógeno del efluente tratado en lagunas anaeróbicas de una extractora de aceite crudo de palma africana, ubicada en la provincia de Esmeraldas, Ecuador. El efluente se purificó en un sistema de laboratorio que consiste en un biofiltro de arena, donde ocurren procesos mecánicos (remoción de la turbidez), biológicos aerobios (eliminación de materia orgánica y nitrificación) y anóxicos (desnitrificación). El sistema consiste en un biofiltro de flujo continuo que descarga a un recipiente de donde se recircula el agua al biofiltro. La remoción de materia orgánica y nitrificación se realizó en intervalos de aireación (8-12 h d −1 ), mientras que la desnitrificación ocurrió en el intervalo de no aireación (12-16 h d −1 ). El sistema operó durante 294 días y se logró una remoción de 41 a 85 % de la DQO y 44 a 87 % de amonio. Así mismo se obtuvo un 12 % de reducción en la concentración de nitrógeno inorgánico total después del intervalo de aireación en comparación con el de no aireación.

Removal of Nitrogenous Compounds from Municipal Wastewater Using a Bacterial Consortium: an Opportunity for More Sustainable Water Treatments

“…The control presented the lowest removal percentage, COD of 17% and BOD 5 of 20%, considering that it worked with the native strains of the affluent. This removal efficiency is attributed to the variables pH, DO, and temperature were target conditions throughout the study, to the bioaugmentation and recirculation, to the increase in the concentration of biomass within the reactor that accelerates the degradation process, and to the extended aeration that provides energy to microorganisms, metabolizing the organic substrate into carbon dioxide and water (Adolfo & Castillo, 2016;Peñafiel et al, 2016). Biofilters help the substrate removal performance because this is the biomass support medium, where they adhere, giving rise to new microorganisms and their development; therefore, with increasing the biofilm surface, an increase is achieved in the performance of substrate removal by microbial activity (Adolfo & Castillo, 2016).…”

“…This study uses a bacterial consortium since it has more efficiency in the elimination of waste in the effluent water than the individual cultures. The assembled consortium is employed as a bioaugmentation agent to establish an eco-friendly practice for the remediation of nitrogenous ammonium and nitrite wastes wastewater (Herrero and Stuckey, 2015;John et al, 2020) and the operation of a treatment system with plug flow processes, extended aeration, and bioaugmentation (FLAEBI), for the removal of CoN (Jia et al, 2019;Peñafiel et al, 2016;Ruscalleda Beylier et al, 2011).…”