title: Proxy model materials to simulate the elastic properties of digested municipal sludge.
abstract: The elastic rheological properties of sludge are complex and evolve with time as a result of ageing and microbial activity. Due to the peculiar nature of sludge, this makes the measurement of physical parameters difficul. The challenge is to identify a reference material that can be used as a proxy for industrial process design or optimization. In this study, respectively the mixtures of 0.5%, 0.7% and 1% glass beads suspension in water have been added to 0.5%, 0.7% and 1% carbopol dissolved in water and neutralized with NaOH to prepare gel, at different ratios. Elastic and loss moduli have been determined for different glass bead suspension ratios in the range of 0%-80%. The results showed that there is a critical glass bead suspension/carbopol ratio at which the elastic properties of the mixture changes dramatically. The elastic properties of these model mixtures of different glass bead/carbopol ratio suspensions are compared with the elastic property of municipal sludge sampled from a Melbourne Waste Water Treatment Plant, and similarity established.
authors.affiliation: Rheology and Materials Processing Centre, Dept. of Chemical Engineering, RMIT University, Victoria 3001, Australia. Electronic address: nicky.eshtiaghi@rmit.edu.au.
authors.forename: Nicky
authors.initials: N
authors.lastname: Eshtiaghi
authors.forename: Flora
authors.initials: F
authors.lastname: Markis
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Baudez
authors.forename: Paul
authors.initials: P
authors.lastname: Slatter
mesh_terms: D008962:Models, Theoretical; D012722:Sewage
chemical_list: D012722:Sewage
keywords: Carbopol gel; Digested municipal sludge; Elastic moduli; Glass bead; Loss moduli