title: The potential use of shear viscosity to monitor polymer conditioning of sewage sludge digestates.
abstract: The work assessed the use of shear viscosity at 0.1 s-1( [Formula: see text] ) as a parameter to detect changes in the conditioning and dewatering of digestates. Total and soluble fractions of organic matter of digestate samples before and after storage were also assessed in regards to their conditioning and dewatering performance. Digestate from a conventional mesophilic anaerobic digestion (CMAD) and advanced anaerobic digestion (AAD) plants were used. Linear regression and correlation analysis of 29 different parameters showed that soluble and total fractions of organic matter (Norg, Sc, Sp, Tp, TKN/COD, tCOD and sCOD) during plant operation and storage conditions correlated (r between 0.80 and 0.99) with the variation in polymer dose, floc strength and CST of conditioned digestate samples. The variations occurred within the content of soluble and total fractions of organic matter, and showed to correlate with both conditioning requirements and the variation in [Formula: see text] . The work concluded that [Formula: see text] measurements of unconditioned digestate samples have the potential to be used as a parameter to monitor conditioning requirements during digestate storage or during process changes. It was found important to analyse soluble and total fractions of organic matter in order to understand the changes in [Formula: see text] within specific process conditions.
authors.affiliation: Wales Centre of Excellence for Anaerobic Digestion, University of South Wales, Pontypridd, CF37 1DL, UK. Electronic address: ivo.oliveira@southwales.ac.uk.
authors.forename: I
authors.initials: I
authors.lastname: Oliveira
authors.affiliation: Sustainable Environmental Research Centre, Faculty of Computing, Engineering and Science, University of South Wales, Pontypridd, CF37 1DL, UK. Electronic address: james.reed@southwales.ac.uk.
authors.forename: J P
authors.initials: JP
authors.lastname: Reed
authors.affiliation: Hazen and Sawyer, Vice President & Residuals Group Practice Leader, One South Broad Street, Suite 1630, Philadelphia, PA 19107, USA. Electronic address: mabuorf@hazenandsawyer.com.
authors.forename: M
authors.initials: M
authors.lastname: Abu-Orf
authors.affiliation: Welsh Water, Nelson, Treharris CF46 6LY, UK. Electronic address: victoria.wilson@dwrcymru.com.
authors.forename: V
authors.initials: V
authors.lastname: Wilson
authors.affiliation: Welsh Water, Nelson, Treharris CF46 6LY, UK. Electronic address: dean.jones@dwrcymru.com.
authors.forename: D
authors.initials: D
authors.lastname: Jones
authors.affiliation: Wales Centre of Excellence for Anaerobic Digestion, University of South Wales, Pontypridd, CF37 1DL, UK. Electronic address: sandra.esteves@southwales.ac.uk.
authors.forename: S R
authors.initials: SR
authors.lastname: Esteves
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D011108:Polymers; D012722:Sewage; D014783:Viscosity
chemical_list: D011108:Polymers; D012722:Sewage
keywords: Conditioning requirements; Digestate management; Digested sewage sludge; Polymer dose monitoring; Rheological characteristics; Storage conditions