Proxy model materials to simulate the elastic properties of digested municipal sludge

• Published in: Water research (Oxford) 2013-10, Vol.47 (15), p.5557-5563
• Main Authors: Eshtiaghi, Nicky, Markis, Flora, Baudez, Jean-Christophe, Slatter, Paul
• Format: Article
• Language: English
• Subjects: Applied sciences; Beads; Carbopol gel; Computer simulation; Digested municipal sludge; Dissolution; Elastic constants; Elastic moduli; Environmental Sciences; Exact sciences and technology; gels; Glass; Glass bead; Loss moduli; loss modulus; microbial activity; Models, Theoretical; Pollution; process design; Proxy client servers; Sewage; Similarity; Sludge; sodium hydroxide; wastewater treatment; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2013.06.027

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. [Display omitted] Similarities and differences between digested municipal sludge and the mixture of carbopol gel and glass bead suspension. •Developing a proxy model material for Elastic properties of digested sludge.•Similar effect between increasing glass bead suspension and sludge concentration.•Existence of critical glass bead ratio for dramatic change of carbopol gel network.•Glass bead/carbopol mixture is a good proxy only for short time process.