Application of CaO2-enhanced peroxone process to adjust waste activated sludge characteristics for dewaterability amelioration: Molecular transformation of dissolved organic matters and realized mechanism of deep-dewatering

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 437; p. 135306
• Main Authors: Ge, Dongdong, Wu, Weixiang, Li, Guangming, Wang, Yuhui, Li, Guobiao, Dong, Yanting, Yuan, Haiping, Zhu, Nanwen
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2022
• Subjects: CaO2/O3 process; Dissolved organic matters; ESI FT-ICR MS; Reactive radicals; Sludge deep-dewatering; Reactive radicals; CaO2/O3 process; Dissolved organic matters; Sludge deep-dewatering; ESI FT-ICR MS
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.135306

[Display omitted] •A novel CaO2/O3 process was developed feasibly for enhancing sludge dewaterability.•CaO2/O3 (60/40 mg/gTS) caused 57.8% sludge solubilization and 46.1% cell death.•DOM composition and transformation were thoroughly analyzed by ESI FT-ICR MS.•CaO2/O3 and PFS treatments eliminated extracellular hydrated DOM complementarily.•Slow H2O2 release and alkalinity induced by CaO2 boosted O3 decomposition validly. Sludge dewaterability is commonly poor due to the hydrophilic biopolymeric substances. The highly efficient oxidation process is of great significance for extracellular biopolymers disintegration and bound water discharge. This work investigated the novel CaO2-enhanced peroxone (CaO2/O3) process to adjust sludge characteristics for dewaterability enhancement and focused on the molecular composition and transformation of dissolved organic matters (DOM). CaO2/O3 (60/40 mg/gTS (total solid)) treatment showed more powerful sludge solubilization of 57.8% and cell death proportion of 46.1% over single CaO2 or O3 treatment. Hydrophilic extracellular polymeric substances, especially protein-like substances, were substantially degraded, and their conformation turned to be more hydrophobic, and carbohydrate-like, aminosugars-like, and lignins-like substances increased in CaO2/O3 process. Meanwhile, CaO2/O3 handling resulted in more decomposition of CHO-containing compounds than N-containing or S-containing compounds. Subsequently, 60 mg/gTS PFS (polyferric sulfate) reflocculation exerted a strengthened role in eliminating proteins & lipids-like, lignins-like, and unsaturated hydrocarbons-like substances, and especially S-containing compounds, which compensated for the unsatisfactory removal effects of these substances in the CaO2/O3 oxidation process. Therefore, the CaO2/O3-PFS treated sludge with less hydrated DOM easily harvested deep-dewatering in pressure filtration. Furthermore, it was noteworthy that the presence of CaO2 created an alkaline environment and served as the source of sustained-release H2O2, which accelerated O3 decomposition and greatly improved •OH generation. These findings provided molecular insight into a novel sludge conditioning approach for ideal dewaterability based on the CaO2-enhanced peroxone process in sludge treatment.