Interpreting the synergistic effect in combined ultrasonication-ozonation sewage sludge pre-treatment
Trzcinski, Antoine Prandota
Ng, Wun Jern
Date of Issue2015
School of Civil and Environmental Engineering
Nanyang Environment and Water Research Institute
Public Utilities Board (PUB), Singapore
The sequential combination of ultrasonication and ozonation as sewage sludge treatment prior to anaerobic digestion was investigated. Synergistic volatile suspended solids (VSS) solubilization was observed when low energy ultrasonication (<12 kJ g−1 TS) was followed by ozonation. 0.048 g O3 g−1 TS ozonation induced the maximum VSS solubilization of 41.3% when the sludge was pre-ultrasonicated at 9 kJ g−1 TS; while, the same ozone dosage applied without prior ultrasonication only induced 21.1% VSS solubilization. High molecular weight (MW) components (MW > 500 kDa) were found to be the main solubilization products when sludge was only ozonated. However, solubilization products by ozone were mainly in the form of low MW components (MW < 27 kDa) when sludge was pre-ultrasonicated. The high MW products generated by ultrasound were effectively degraded in the subsequent ozonation. Anaerobic biodegradability increased by 34.7% when ultrasonication (9 kJ g−1 TS) and ozonation (0.036 g O3 g−1 TS) were combined sequentially. The maximum methane production rate increased from 3.53 to 4.32, 4.21 and 4.54 mL CH4 d−1 after ultrasonication, ozonation and ultrasonication–ozonation pre-treatments, respectively.
DRNTU::Engineering::Environmental engineering::Waste management
© 2014 Elsevier. This is the author created version of a work that has been peer reviewed and accepted for publication by Chemosphere, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.chemosphere.2014.09.007].