title: Determination of denitrifying sludge settleability using contact angle measurements.
abstract: The adaptation of the technique for measuring the contact angle (CA) in order to follow the changes of sludge settleability of a denitrifying sludge surface is described. Denitrifying sludge was continuously fed into an upflow anaerobic sludge blanket (UASB) reactor with acetate and nitrate. The loss of settleability in the sludge was induced by decreasing the hydraulic residence time (HRT) from 1 d to 0.125 d. CA was measured with air and nitrogen bubbles. A comparison between sludge volume index (SVI) and the CA and their correlation with sludge settleability was carried out. Results showed that CA method had a high correlation with sludge settleability. Moreover the CA method showed to be simpler and less time consuming than the SVI method.
authors.affiliation: Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Física, Av. San Rafael Atlixco 186, col. Vicentina C. P. 09340, Mexico.
authors.forename: J A
authors.initials: JA
authors.lastname: Lopez-Barrera
authors.forename: A
authors.initials: A
authors.lastname: Peña-Calva
authors.forename: R
authors.initials: R
authors.lastname: Olayo
authors.forename: J
authors.initials: J
authors.lastname: Gómez
authors.forename: F
authors.initials: F
authors.lastname: Cuervo-López
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods; D008800:Mexico; D009566:Nitrates / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry*; D013499:Surface Properties; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D009566:Nitrates; D012722:Sewage