title: Biodegradability and methane production from secondary paper and pulp sludge: effect of fly ash and modeling.
abstract: The effect of fly ash on biodegradability and methane production from secondary paper and pulp sludge, including its modeling, was evaluated. Three tests with fly ash concentrations of 0, 10 and 20 mg/L were evaluated at 32 °C. Methane production was modeled using the modified Gompertz equation. The results show that the doses used produce a statistically significant increase of accumulated methane, giving values greater than 225 mL of CH4 per gram of volatile solids (VS) added, and 135% greater than that obtained in the control assay. Biodegradability of VS increased 143% with respect to the control assays, giving values around 43%. The modified Gompertz model can describe well methane generation from residual sludge of the paper industry water treatment, with parameter values between those reported in the literature. Thus, the addition of fly ash to the process causes a significant increase of accumulated methane and VS removal, improving the biodegradability of paper and pulp sludge.
authors.affiliation: Department of Chemical Engineering, Universidad de Santiago de Chile, Santiago, Chile E-mail: cesar.huilinir@usach.cl.
authors.forename: César
authors.initials: C
authors.lastname: Huiliñir
authors.affiliation: Department of Chemical Engineering, Universidad de Santiago de Chile, Santiago, Chile E-mail: cesar.huilinir@usach.cl.
authors.forename: Silvio
authors.initials: S
authors.lastname: Montalvo
authors.affiliation: Department of Chemical and Environmental Engineering, Universidad Técnica Federico Santa Marıa, Valparaıso, Chile.
authors.forename: Lorna
authors.initials: L
authors.lastname: Guerrero
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D060729:Coal Ash / Q000737:chemistry*; D008697:Methane / Q000032:analysis*; D008962:Models, Theoretical; D010209:Paper; D059027:Recycling; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D012722:Sewage / Q000737:chemistry*; D014866:Waste Products / Q000032:analysis*; D018508:Water Purification / Q000379:methods
chemical_list: D060729:Coal Ash; D012722:Sewage; D014866:Waste Products; D008697:Methane