1. Combined free nitrous acid and hydrogen peroxide pre-treatment of waste activated sludge enhances methane production via organic molecule breakdown
- Author
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Qilin Wang, Zhiguo Yuan, Tingting Zhang, Liu Ye, and Damien J. Batstone
- Subjects
Nitrous acid ,Multidisciplinary ,Sewage ,Chemical structure ,Deamination ,Nitrous Acid ,Hydrogen Peroxide ,Biodegradation ,Models, Theoretical ,Waste Disposal, Fluid ,Methane ,Article ,Water Purification ,chemistry.chemical_compound ,Activated sludge ,Biodegradation, Environmental ,Bioreactors ,chemistry ,Bioreactor ,Hydrogen peroxide ,Nuclear chemistry - Abstract
This study presents a novel pre-treatment strategy using combined free nitrous acid (FNA i.e. HNO2) and hydrogen peroxide (H2O2) to enhance methane production from WAS, with the mechanisms investigated bio-molecularly. WAS from a full-scale plant was treated with FNA alone (1.54 mg N/L), H2O2 alone (10–80 mg/g TS) and their combinations followed by biochemical methane potential tests. Combined FNA and H2O2 pre-treatment substantially enhanced methane potential of WAS by 59–83%, compared to 13–23% and 56% with H2O2 pre-treatment alone and FNA pre-treatment alone respectively. Model-based analysis indicated the increased methane potential was mainly associated with up to 163% increase in rapidly biodegradable fraction with combined pre-treatment. The molecular weight distribution and chemical structure analyses revealed the breakdown of soluble macromolecules with the combined pre-treatment caused by the deamination and oxidation of the typical functional groups in proteins, polysaccharides and phosphodiesters. These changes likely improved the biodegradability of WAS.
- Published
- 2015