Anaerobic-aerobic treatment of swine wastewater in uasb and batch reactors in series

Abstract

In this work it was evaluated the performance of two systems of swine wastewater treatment consisting of two-stage upflow anaerobic sludge blanket (UASB) reactors, with and without post-treatment in sequencing batch reactor (SBR), fed continuously, with aerobic phase. The UASB reactors in the first stage had 908 L in the sets I and II, and in the second stage 350 and 188 L, respectively. In the set II the post-treatment was performed in a SBR of 3,000 L. The hydraulic detention times in the anaerobic treatment systems were 100, 75 and 58 h in the set I; 87, 65 and 51 h in the set II; and 240 and 180 h in the SBR. The volumetric organic load applied in the first stage UASB reactors ranged from 6.9 to 12.6 g total COD (L d) -1 in the set I and 7.5 to 9.8 g total COD (L d) -1 in the set II. The average removal efficiencies of total COD, total phosphorus (P total ), and Kjeldahl and organic nitrogen (KN and N org ) in the anaerobic treatment systems were similar and reached maximum values of 97%, 64%, 68%, and 98%. In the SBR, the removal efficiencies of total COD and thermotolerant coliforms were up to 62 and 92% resulting, respectively, in effluent concentrations of 135 mg L -1 and 2x10 4 MPN (100 mL) -1 . For P total , total nitrogen (TN) and N org , the average removal efficiencies in the SBR were up to 58, 25 and 73%, respectively. Anaerobic-aerobic treatment of swine wastewater in UASB and batch reactors in series Eng. KEYWORDS

Start-up of a UASB reactor for the treatment of wastewater from the intensive breeding of pigs

“…La crianza porcina intensiva reúne un elevado número de animales por área (Córdova et al, 2017), e implica la generación de grandes cantidades de residuos sólidos y líquidos, que deben ser manejados de manera apropiada (Serafine et al 2015;Córdova et al, 2017;Xu et al, 2016;Bosco et al, 2016;Amaral et al, 2014), porque de lo contrario pueden originar problemas ambientales (Cho et al, 2013;Antezana et al, 2016) asociados con su alto contenido en materia orgánica y nutrientes (Cho et al, 2013), tales como, malos olores (Xu et al, 2016;Ortiz et al, 2014), emisión de gas metano (Xu et al, 2016;Antezana et al, 2016) y contaminación del agua superficial y subterránea (Xu et al, 2016). En este contexto, investigaciones previas (Ramires y Oliveira et al, 2014;Pinto et al, 2014;Urbinati, et al, 2013;Duda et al, 2011;Santana et al, 2005;Foresti et al, 1995;Urbinati et al, 2014) presentan al reactor UASB como una tecnología eficaz en la remoción de materia orgánica de las aguas residuales derivadas de la porcicultura intensiva, con eficiencias de eliminación de DQO mayores al 55%, operando a temperaturas en el rango mesofílico y a velocidades de carga orgánica (VCO) entre 1,2 y 40 kg DQO.m -3 .d -1 . En el reactor UASB, la obtención de buenas eficiencias de remoción a elevadas velocidades de carga orgánica depende principalmente del desarrollo y retención de alta concentración de biomasa activa y sedimentable, capaz de convertir la materia orgánica del agua residual en metano y CO2 y, de separarse eficientemente del efluente tratado (Hickey et al, 1991).…”