1. Hybrid process combining ultrafiltration and electro-oxidation for COD and nonylphenol ethoxylate removal from industrial laundry wastewater.
- Author
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Khajvand M, Drogui P, Arab H, Tyagi RD, and Brien E
- Subjects
- Biological Oxygen Demand Analysis, Phenols chemistry, Endocrine Disruptors chemistry, Laundering, Wastewater chemistry, Oxidation-Reduction, Water Pollutants, Chemical chemistry, Waste Disposal, Fluid methods, Ultrafiltration methods, Ethylene Glycols chemistry
- Abstract
Laundry wastewater is a significant source of nonylphenol ethoxylate (NPEO) at wastewater treatment plants, where its breakdown forms persistent nonylphenol (NP). NP poses risks as an endocrine disruptor in wildlife and humans. This study investigates the degradation of NPEO and COD in industrial laundry wastewater (LWW) using a two-stage process combining ultrafiltration (UF) and electro-oxidation (EO). UF was used to remove suspended solids, while soluble COD (COD
0 = 239 ± 6 mg.L-1 ) and NPEO (NPEO0 = 341 ± 8 μg.L-1 ) were oxidized by the EO process. Different operating parameters were studied such as current density, electrolysis time, type of cathode and supporting electrolyte concentration. Using an experimental design methodology, the optimal conditions for COD and NPEO3-17 degradation were recorded. This included achieving 97% degradation of NPEO3-17 and 61% degradation of COD, with a total operating cost of 3.65 USD·m-3 . These optimal conditions were recorded at a current density of 15 mA cm-2 for a 120-min reaction period in the presence of 4 g·Na2 SO4 L-1 using a graphite cathode. The EO process allowed for reaching the guidelines required for water reuse (NPEO <200 μg.L-1 , COD <100 mg.L-1 ) in the initial laundry washing cycles. Furthermore, our results demonstrate that both NP and NPEO compounds, including higher and shorter ethoxylate chains (NPEO3-17 ), were effectively degraded during the EO process, with removal efficiencies between 94% and 98%. This confirms the EO process's capability to effectively degrade NP, the by-product of NPEO breakdown., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Patrick Drogui reports financial support was provided by National Sciences and Engineering Research Council of Canada. Patrick Drogui reports financial support was provided by CREATE TEDGIEER program. Patrick Drogui reports financial support was provided by Group VEOS. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
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