ORCID Profile
0000-0002-8325-5783
Current Organisation
RMIT University
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Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.WATRES.2019.03.039
Abstract: Rheological properties are important in the design and operation of sludge-handling process. Despite this, the rheology of sludge in thermal hydrolysis processes (TH) is not well described. In-situ measurements were performed to characterize the flow behaviour of various concentrations (7-13 wt%) of waste activated sludge (WAS) at TH conditions. Equations were presented for predicting in-situ rheological parameters (high-shear viscosity, η
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.WATRES.2018.02.059
Abstract: Sludge pumps in wastewater treatment plants are often oversized due to uncertainty in calculation of pressure drop. This issue costs millions of dollars for industry to purchase and operate the oversized pumps. Besides costs, higher electricity consumption is associated with extra CO
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.SCITOTENV.2017.09.206
Abstract: Appropriate sewage sludge rheological models are essential for computational fluid dynamic simulation of wastewater treatment processes, in particular aerobic and anaerobic digestions. The liquid-like behaviour of sludge is well documented but the solid-like behaviour remains poorly described despite its importance for dead-zone formation. In this study, classical Kelvin-Voigt model, commonly used for sludge in literature, were compared with fractional derivative Kelvin-Voigt model regarding their predictive ability for describing the solid-like behaviour. Results showed that the fractional Kelvin-Voigt model best fitted the experimental data obtained from creep and frequency sweep tests. Whereas, classical Kelvin-Voigt could not fit the frequency sweep data as this model is not a function of angular velocity. Also, the Kelvin-Voigt model was unable to predict the creep data at low stresses.
Publisher: Informa UK Limited
Date: 14-12-2017
Publisher: Wiley
Date: 30-03-2014
DOI: 10.1002/PEN.23555
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 06-2014
DOI: 10.1016/J.WATRES.2014.02.048
Abstract: This study investigated the partially irreversible effect of thermal treatment on the rheology of digested sludge when it was subjected to temperature change between 20 °C and 80 °C and then cooled down to 20 °C. The yield stress, infinite viscosity and liquor viscosity of sludge were measured at 20 °C for different thermal histories and were compared to the evolution of the solubilised chemical oxygen demand (COD) of sludge liquor. The results showed that thermal history irreversibly affects sludge rheology as the yield stress of sludge which was heated to 80 °C then cooled down to 20 °C was 68% lower than the initial yield stress at 20 °C. This decrease was due to the irreversible solubilisation of solid matter during heating as underlined by soluble COD data which did not reach its original level after thermal treatment. Measured soluble COD of sludge which was heated and cooled down was much higher than the soluble COD of initial sludge. We found a proportionality of the increase of soluble COD with the decrease of the yield stress as well as increase of infinite viscosity.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Informa UK Limited
Date: 13-01-2017
DOI: 10.1080/10934529.2016.1270674
Abstract: In a wastewater treatment process, energy is mainly used in sludge handling and heating, while energy is recovered by biogas production in anaerobic digestion process. Thermal pre-treatment of sludge can change the energy balance in a wastewater treatment process since it reduces the viscosity and yield stress of sludge and increases the biogas production. In this study, a calculation based on a hypothetical wastewater treatment plant is provided to show the possibility of creating a net positive energy wastewater treatment plant as a result of implementing thermal pre-treatment process before the anaerobic digester. The calculations showed a great energy saving in pumping and mixing of the sludge by thermal pre-treatment of sludge before anaerobic digestion process.
Publisher: Elsevier BV
Date: 11-2016
Publisher: Informa UK Limited
Date: 06-2012
Location: Iran (Islamic Republic of)
Location: Iran (Islamic Republic of)
No related grants have been discovered for Ehsan Farno.