title: Biomass adaptation over anaerobic co-digestion of sewage sludge and trapped grease waste.
abstract: The feasibility of sewage sludge co-digestion using intermediate waste generated inside a wastewater treatment plant, i.e. trapped grease waste from the dissolved air flotation unit, has been assessed in a continuous stirred lab reactor operating at 35°C with a hydraulic retention time of 20 days. Three different periods of co-digestion were carried out as the grease waste dose was increased. When the grease waste addition was 23% of the volatile solids fed (organic loading rate 3.0 kg(COD)m(-3)d(-1)), an increase in methane yield of 138% was reported. Specific activity tests suggested that anaerobic biomass had adapted to the co-substrate. The adapted inoculum showed higher acetoclastic methanogenic and β-oxidation synthrophic acetogenic activities but lower hydrogenotrophic methanogenic activity. The results indicate that a slow increase in the grease waste dose could be a strategy that favours biomass acclimation to fat-rich co-substrate, increases long chain fatty acid degradation and reduces the latter's inhibitory effect.
authors.affiliation: GIRO Technological Centre, Rbla. Pompeu Fabra 1, E-08100 Mollet del Vallès, Barcelona, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Silvestre
authors.forename: A
authors.initials: A
authors.lastname: Rodríguez-Abalde
authors.forename: B
authors.initials: B
authors.lastname: Fernández
authors.forename: X
authors.initials: X
authors.lastname: Flotats
authors.forename: A
authors.initials: A
authors.lastname: Bonmatí
mesh_terms: D000222:Adaptation, Physiological; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005232:Fatty Acids, Volatile / Q000032:analysis; D006859:Hydrogen / Q000032:analysis; D008697:Methane / Q000032:analysis; D009821:Oils / Q000737:chemistry*; D010313:Partial Pressure; D012722:Sewage / Q000382:microbiology*; D014835:Volatilization; D014866:Waste Products / Q000032:analysis*
chemical_list: D005232:Fatty Acids, Volatile; D009821:Oils; D012722:Sewage; D014866:Waste Products; D006859:Hydrogen; D008697:Methane