Khajvand Mahdieh, Drogui Patrick, Arab Hamed, Tyagi Rajeshwar Dayal, Brien Emmanuel
Institut National de La Recherche Scientifique (INRS), Centre-Eau Terre Environnement (ETE), Université Du Québec, 490 Rue de La Couronne, Québec, G1K 9A9, Canada.
Institut National de La Recherche Scientifique (INRS), Centre-Eau Terre Environnement (ETE), Université Du Québec, 490 Rue de La Couronne, Québec, G1K 9A9, Canada.
Chemosphere. 2024 Sep;363:142931. doi: 10.1016/j.chemosphere.2024.142931. Epub 2024 Jul 23.
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 = 239 ± 6 mg.L) and NPEO (NPEO = 341 ± 8 μg.L) 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 NPEO degradation were recorded. This included achieving 97% degradation of NPEO and 61% degradation of COD, with a total operating cost of 3.65 USD·m. These optimal conditions were recorded at a current density of 15 mA cm for a 120-min reaction period in the presence of 4 g·NaSO L using a graphite cathode. The EO process allowed for reaching the guidelines required for water reuse (NPEO <200 μg.L, COD <100 mg.L) in the initial laundry washing cycles. Furthermore, our results demonstrate that both NP and NPEO compounds, including higher and shorter ethoxylate chains (NPEO), 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.
洗衣废水是污水处理厂中壬基酚聚氧乙烯醚（NPEO）的重要来源，在那里其分解会形成持久性壬基酚（NP）。NP作为一种内分泌干扰物，对野生动物和人类构成风险。本研究采用超滤（UF）和电氧化（EO）相结合的两阶段工艺，研究了工业洗衣废水（LWW）中NPEO和化学需氧量（COD）的降解情况。超滤用于去除悬浮固体，而可溶性COD（COD = 239 ± 6 mg·L）和NPEO（NPEO = 341 ± 8 μg·L）则通过电氧化工艺进行氧化。研究了不同的操作参数，如电流密度、电解时间、阴极类型和支持电解质浓度。采用实验设计方法，记录了COD和NPEO降解的最佳条件。这包括实现NPEO降解97%和COD降解61%，总运行成本为3.65美元·m。这些最佳条件是在使用石墨阴极、电流密度为15 mA·cm²、反应时间为120分钟、存在4 g·L⁻¹ Na₂SO₄的情况下记录的。电氧化工艺在初始洗衣洗涤循环中能够达到水回用所需的指导标准（NPEO < 200 μg·L，COD < 100 mg·L）。此外，我们的结果表明，在电氧化过程中，包括较长和较短乙氧基链（NPEO）的NP和NPEO化合物均被有效降解，去除效率在94%至98%之间。这证实了电氧化工艺有效降解NPEO分解副产物NP的能力。
