title: Effect of agitation on the performance of an anaerobic sequencing batch biofilm reactor in the treatment of dairy effluents.
abstract: Agitation rate is an important parameter in the operation of Anaerobic Sequencing Biofilm Batch Reactors (ASBBRs), and a proper agitation rate guarantees good mixing, improves mass transfer, and enhances the solubility of the particulate organic matter. Dairy effluents have a high amount of particulate organic matter, and their anaerobic digestion presents inhibitory intermediates (e.g., long-chain fatty acids). The importance of studying agitation in such batch systems is clear. The present study aimed to evaluate how agitation frequency influences the anaerobic treatment of dairy effluents. The ASBBR was fed with wastewater from milk pasteurisation process and cheese manufacture with no whey segregation. The organic matter concentration, measured as chemical oxygen demand (COD), was maintained at approximately 8,000 mg/L. The reactor was operated with four agitation frequencies: 500 rpm, 350 rpm, 200 rpm, and no agitation. In terms of COD removal efficiency, similar results were observed for 500 rpm and 350 rpm (around 90%) and for 200 rpm and no agitation (around 80%). Increasing the system's agitation thus not only improved the global efficiency of organic matter removal but also influenced volatile acid production and consumption and clearly modified this balance in each experimental condition.
authors.affiliation: Environmental Biotechnology Laboratory - Department of Food Engineering - College of Animal Science and Food Engineering University of Sao Paulo - Av Duque de Caxias Norte 225. Pirassununga - SP, CEP 13565-900. thais_zpenteado@yahoo.com.br
authors.forename: T Z
authors.initials: TZ
authors.lastname: Penteado
authors.forename: R S S
authors.initials: RS
authors.lastname: Santana
authors.forename: A L B
authors.initials: AL
authors.lastname: Dibiazi
authors.forename: S C
authors.initials: SC
authors.lastname: de Pinho
authors.forename: R
authors.initials: R
authors.lastname: Ribeiro
authors.forename: G
authors.initials: G
authors.lastname: Tommaso
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D018441:Biofilms; D019149:Bioreactors; D002417:Cattle; D003612:Dairying; D007700:Kinetics; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014873:Water Pollutants
chemical_list: D014873:Water Pollutants