MP-UV/CaO2 as a pretreatment method for the removal of carbamazepine and primidone in waste activated sludge and improving the solubilization of sludge

Ming Zheng; Yongmei Li; Qian Ping; Lin Wang

doi:10.1016/j.watres.2018.11.086

MP-UV/CaO₂ as a pretreatment method for the removal of carbamazepine and primidone in waste activated sludge and improving the solubilization of sludge

Water Res. 2019 Mar 15:151:158-169. doi: 10.1016/j.watres.2018.11.086. Epub 2018 Dec 18.

Authors

Ming Zheng¹, Yongmei Li², Qian Ping¹, Lin Wang³

Affiliations

¹ State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
² State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China. Electronic address: liyongmei@tongji.edu.cn.
³ State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.

PMID: 30594084
DOI: 10.1016/j.watres.2018.11.086

Abstract

Medium-pressure ultraviolet light (MP-UV) combined with calcium peroxide (CaO₂) as a pretreatment technology for removing carbamazepine (CBZ) and primidone (PMD) in waste active sludge (WAS) and improving the solubilization of sludge were investigated. CBZ and PMD were effectively removed and the removal fitted pseudo-first kinetics under MP-UV/CaO₂ treatment with R² > 0.97. The higher CaO₂ dosage and lower initial volatile suspended solids (VSS) concentration were conductive to the removal of CBZ and PMD. Of the CaO₂ hydrolysates, Ca(OH)₂ played a more important role than H₂O₂ during MP-UV/CaO₂ treatment. The removal of the target compounds was attributed to direct photolysis and indirect photolysis caused by •OH, ³DOM^*, and ¹O₂, in which •OH played a vital role with > 62.2% contribution to the overall degradation rate. A model predicting the steady concentration of •OH in WAS ([VSS] ≈ 8.6 g L^-1) under MP-UV/CaO₂ treatment with CaO₂ dosage ranging from 0 to 0.5 g g^-1-VSS was proposed and validated. Moreover, major intermediates of CBZ and PMD were detected and the probable transformation pathways during MP-UV/CaO₂ treatment were proposed. In addition, MP-UV/CaO₂ promoted the sludge solubilization effectively. Considering both the pharmaceutical degradation and sludge solubilization, the optimum operation condition with 0.2 g-CaO₂ g^-1-VSS combined with 7 h MP-UV irradiation is recommended. Under this condition, more than 92.3% of CBZ and 90.3% of PMD were removed, and soluble chemical oxygen demand (SCOD) increased by 657% and 13.6% compared with sole 10 h CaO₂ (0.2 g g^-1-VSS) treatment and 7 h MP-UV treatment, respectively.

Keywords: Carbamazepine (CBZ) and primidone (PMD); Degradation pathway; MP-UV/CaO(2) pretreatment; Sludge solubilization; Waste activated sludge (WAS).

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbamazepine
Hydrogen Peroxide
Primidone*
Sewage*
Ultraviolet Rays
Waste Disposal, Fluid

Substances

Sewage
Primidone
Carbamazepine
Hydrogen Peroxide