title: Feeding schemes and C/N ratio of a laboratory-scale step-fed sequencing batch reactor for liquid swine manure treatment.
abstract: This study was undertaken to investigate the effect of two split feeding schemes (600 mL/200 mL and 400 mL/400 mL, designated as FS1 and FS2, respectively) on the performance of a step-fed sequencing batch reactor (SBR) in treating liquid swine manure for nutrient removal. The SBR was run on an 8-h cycle with a repeated pattern of anaerobic/anoxic/aerobic phases in each cycle and the two feedings always occurred at the beginning of each anaerobic phase. A low-level aeration was used (1.0 L/m3.sec) for the anoxic/aerobic phase to facilitate nitrification and phosphorus uptake while reducing the energy consumption. The results showed that FS1 reduced NH4+-N by 98.7% and FS2 by 98.3%. FS1 had 12.3 mg/L NO3-N left in the effluent, while FS2 had 4.51 mg/L. For soluble phosphorus removal, FS1 achieved 95.2%, while FS2 reached only 68.5%. Both feeding schemes achieved ≥ 95% removal of COD. A good power regression was observed between total nitrogen (sum of all three nitrogen species) and the carbon to nitrogen (C/N) ratio, with the correlation coefficients of 0.9729 and 0.9542 for FS1 and FS2, respectively, based on which it was concluded that higher C/N ratios were required to achieve higher nitrogen removal efficiencies.
authors.affiliation: a Department of Biological Engineering , University of Idaho , Moscow , Idaho , USA.
authors.forename: Sarah Xiao
authors.initials: SX
authors.lastname: Wu
authors.affiliation: b Department of Biological and Agricultural Engineering , University of Arkansas , Fayetteville , AR , USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
authors.affiliation: c Soil and Water Systems, University of Idaho , Twin Falls , Idaho , USA.
authors.forename: Lide
authors.initials: L
authors.lastname: Chen
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D000818:Animals; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D002244:Carbon / Q000032:analysis*; D008372:Manure; D059013:Microbial Consortia; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*; D013552:Swine; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis
chemical_list: D002244:Carbon; D008372:Manure; D009584:Nitrogen; D010758:Phosphorus; D062065:Wastewater
keywords: carbon to nitrogen ratio; nutrients removal; sequencing batch reactor; step-fed strategy; swine wastewater