title: Effect of particulate organic substrate on aerobic granulation and operating conditions of sequencing batch reactors.
abstract: The formation and application of aerobic granules for the treatment of real wastewaters still remains challenging. The high fraction of particulate organic matter (XS) present in real wastewaters can affect the granulation process. The present study aims at understanding to what extent the presence of XS affects the granule formation and the quality of the treated effluent. A second objective was to evaluate how the operating conditions of an aerobic granular sludge (AGS) reactor must be adapted to overcome the effects of the presence of XS. Two reactors fed with synthetic wastewaters were operated in absence (R1) or presence (R2) of starch as proxy for XS. Different operating conditions were evaluated. Our results indicated that the presence of XS in the wastewater reduces the kinetic of granule formation. After 52 d of operation, the fraction of granules reached only 21% in R2, while in R1 this fraction was of 54%. The granules grown in presence of XS had irregular and filamentous outgrowths in the surface, which affected the settleability of the biomass and therefore the quality of the effluent. An extension of the anaerobic phase in R2 led to the formation of more compact granules with a better settling ability. A high fraction of granules was obtained in both reactors after an increase of the selection pressure for fast-settling biomass, but the quality of the effluent remained low. Operating the reactors in a simultaneous fill-and-draw mode at a low selection pressure for fast-settling biomass showed to be beneficial for substrate removal efficiency and for suppressing filamentous overgrowth. Average removal efficiencies for total COD, soluble COD, ammonium, and phosphate were 87 ± 4%, 95 ± 1%, 92 ± 10%, and 87 ± 12% for R1, and 72 ± 12%, 86 ± 5%, 71 ± 12%, and 77 ± 11% for R2, respectively. Overall our study demonstrates that the operating conditions of AGS reactors must be adapted according to the wastewater composition. When treating effluents that contain XS, the selection pressure should be significantly reduced.
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Process Engineering, CH-8600 Dübendorf, Switzerland; Federal University of Santa Catarina (UFSC), Department of Sanitary and Environmental Engineering, 88040-970 Florianópolis, Santa Catarina, Brazil.
authors: Jamile
authors: J
authors: Wagner
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Process Engineering, CH-8600 Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, CH-8093 Zürich, Switzerland.
authors: David Gregory
authors: DG
authors: Weissbrodt
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Process Engineering, CH-8600 Dübendorf, Switzerland.
authors: Vincent
authors: V
authors: Manguin
authors: Federal University of Santa Catarina (UFSC), Department of Sanitary and Environmental Engineering, 88040-970 Florianópolis, Santa Catarina, Brazil.
authors: Rejane Helena Ribeiro
authors: RH
authors: da Costa
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Process Engineering, CH-8600 Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, CH-8093 Zürich, Switzerland.
authors: Eberhard
authors: E
authors: Morgenroth
authors: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Process Engineering, CH-8600 Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, CH-8093 Zürich, Switzerland. Electronic address: nicolas.derlon@eawag.ch.
authors: Nicolas
authors: N
authors: Derlon
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors; D007700:Kinetics; D009930:Organic Chemicals / Q000378:metabolism*; D052638:Particulate Matter / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry; D012722:Sewage / Q000737:chemistry; D013213:Starch / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater; D018508:Water Purification / Q000379:methods*
chemical_list: D064751:Ammonium Compounds; D009930:Organic Chemicals; D052638:Particulate Matter; D010758:Phosphorus; D012722:Sewage; D013213:Starch; D062065:Wastewater
keywords: Aerobic granules; Particulate organic substrate; Selection pressure; Simultaneous fill-and-draw operation