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Environ Pollut

Title:		Simultaneous degradation of microplastics and sludge during wet air oxidation
Author(s):		Wang L; Liu J; Li H;
Address:		"Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China. Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China. Electronic address: li.huan@sz.tsinghua.edu.cn"
Journal Title:		Environ Pollut
Year:		2023
Volume:		20230808
Issue:
Page Number:		122348 -
DOI:		10.1016/j.envpol.2023.122348
ISSN/ISBN:		1873-6424 (Electronic) 0269-7491 (Linking)
Abstract:		"Microplastics (MPs) generated from daily life are commonly collected by urban sewage pipe networks and then transfer to sludge in wastewater treatment plants. Conventional biochemical treatment processes cannot degrade MPs effectively, causing an ecological risk via sludge land use. Wet air oxidation (WAO) is a promising sludge treatment technology with a strong ability to decompose complex organic matter, but its potential for the removal of MPs in sludge was unclear. In this study, three common MPs (polyethylene, polystyrene, and polyethylene terephthalate, which are called PEMPs, PSMPs, and PETMPs) were added into the sludge samples (1 g MP in 180 mL sludge), to test the effects of WAO on sludge and MPs. The results showed that WAO simultaneously degraded sludge and the PEMPs, and the two degradation processes were relatively independent when oxygen was supplied adequately. The dissolution of PSMPs and organic matter in sludge was not affected by each other, but the degradation rate was slowed down due to the interaction of ketones and benzene compounds. The hydrolysis of sludge and PETMPs was accelerated, while the hydrolyzed products such as terephthalic acid were oxidized without interfering with each other. No obvious MPs remained in the effluent, and volatile fatty acids (VFAs) were the main components, among which acetic acid accounted for 90%. When the sludge was treated with PEMPs, PSMPs, or PETMPs, the concentration of acetic acid finally accounted for 45%, 21%, and 18% of DOC. Overall, MPs can be degraded or even mineralized during sludge WAO, and humic acid derivatives, acetate, and other small molecules of alcohols, ketones, or aldehydes were the typical intermediates"
Keywords:		"*Sewage/chemistry *Microplastics Plastics Waste Disposal, Fluid/methods Acetates Acetic acid Degradation Microplastics Sludge Wet air oxidation;"
Notes:		"MedlineWang, Lin Liu, Jiayi Li, Huan eng England 2023/08/11 Environ Pollut. 2023 Oct 15; 335:122348. doi: 10.1016/j.envpol.2023.122348. Epub 2023 Aug 8"