Performance of an anaerobic-aerobic reactor and kinetic study of organic matter removal of cattle slaughterhouse effluent

Abstract

This paper sought to evaluate the behavior of an upflow Anaerobic-Aerobic Fixed Bed Reactor (AAFBR) in the treatment of cattle slaughterhouse effluent and determine apparent kinetic constants of the organic matter removal. The AAFBR was operated with no recirculation (Phase I) and with 50% of effluent recirculation (Phase II), with θ of 11h and 8h. In terms of pH, bicarbonate alkalinity and volatile acids, the results indicated the reactor ability to maintain favorable conditions for the biological processes involved in the organic matter removal in both operational phases. The average removal efficiencies of organic matter along the reactor height, expressed in terms of raw COD, were 49% and 68% in Phase I and 54% and 86% in Phase II for θ of 11h and 8h, respectively. The results of the filtered COD indicated removal efficiency of 52% and k = 0.0857h -1 to θ of 11h and 42% and k = 0.0880h -1 to θ of 8h in the Phase I. In Phase II, the removal efficiencies were 59% and 51% to θ of 11h and 8h, with k = 0.1238h -1 and k = 0.1075 h -1 , respectively. The first order kinetic model showed good adjustment and described adequately the kinetics of organic matter removal for θ of 11h, with r 2 equal to 0.9734 and 0.9591 to the Phases I and II, respectively. KEYWORDS: kinetic, cattle slaughterhouse, combined treatment system. DESEMPENHO DE UM REATOR ANAERÓBIO-AERÓBIO E ESTUDO CINÉTICO DE REMOÇÃO DE MATÉRIA ORGÂNICA DE EFLUENTE BOVINORESUMO: O objetivo deste estudo foi avaliar o desempenho de um Reator Anaeróbio-Aeróbio de Leito Fixo (RAALF) com escoamento ascendente, no tratamento de efluente bruto de matadouro bovino, e obter constantes cinéticas aparentes da remoção de matéria orgânica. O RAALF foi operado sem recirculação (Etapa I) e com 50% de recirculação do efluente (Etapa II), com θ de 11 h e 8 h. Em termos de pH, alcalinidade a bicarbonato e ácidos voláteis, os resultados indicaram que o RAALF apresentou capacidade em manter condições favoráveis para os processos biológicos envolvidos na remoção de matéria orgânica, em ambas as etapas operacionais. As eficiências médias de remoção de matéria orgânica ao longo da altura do reator, expressa em termos de DQO bruta, foram de 49% e 68% na Etapa I e de 54% e 86% na Etapa II, para θ de 11 h e 8 h, respectivamente. Os resultados de DQO filtrada indicaram eficiências de remoção de 52% e k = 0,0857 h -1 para θ de 11 h e 42% e k = 0,0880 h -1 para θ de 8 h na Etapa I. Na Etapa II, as eficiências de remoção foram 59% e 51% para θ de 11 h e 8 h, com k = 0,1238 h -1 e k = 0,1075 h -1 , respectivamente. O modelo cinético de primeira ordem indicou bom ajuste e descreveu adequadamente a cinética de remoção de matéria orgânica para θ de 11 h, com r 2 igual a 0,9734 e 0,9591 para as Etapas I e II, respectivamente.

<b>Effect of hydraulic retention time on hydrodynamic behavior of anaerobic-aerobic fixed bed reactor treating cattle slaughterhouse effluent

“…), respectively. Similar behavior was observed by Kreutz, Passig, Carvalho, Mees, and Gomes (2014) that verified 59% of organic matter removal in the same configuration of the reactor treating raw cattle slaughterhouse effluent; and Abreu and Zaiat (2008) that obtained removal of 37% to COD when an anaerobic-aerobic reactor was operated with θ t of 8 hours, increasing to 46% when the θ t was reduced to 6 hours in the treatment of sewage.…”

“…Carvalho et al (2008) attributed the long tailing phenomenon to the diffusion of the tracer eosin Y in dead zones and its slow release in the effluent of a UASB reactor (160 L) applied in the treatment of sewage. Kreutz et al (2014) also observed the long tail effect in an anaerobicaerobic combined reactor, treating cattle slaughterhouse wastewater, and attributed this phenomenon to the adsorption of eosin Y in the support medium utilized for biomass immobilization. Levenspiel (2000) noticed that the long tail is related to some hydrodynamics aspects such as the tracer diffusion in dead zones of the reactor, tracer adsorption in the biomass of the reactor or the presence of hydraulic shortcircuiting.…”

Kinetic Study of Anaerobic Digestion of Ketchup Industry Wastewater in a Three-stages Anaerobic Baffled Reactor (ABR)

“…Stover-Kincannon derived the kinetic model for biofilm reactor based on the total organic loading rate. The modified model of Stover-Kincannon described total organic loading rate as the primary parameter to explain the kinetic of an Anaerobic Filter (AF) by means of organic substance removal and methane production [25]. Stover-Kincannon model was applied to analyze the reactor removal efficiency at the fixed bed region with different organic loading rate [26].…”