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 (COD0 = 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·Na2SO4 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.
摘要：
洗衣废水是污水处理厂壬基酚乙氧基化物（NPEO）的重要来源，其分解形成持久性壬基酚(NP)。NP作为野生动物和人类的内分泌干扰物存在风险。本研究使用结合超滤（UF）和电氧化（EO）的两阶段工艺研究了工业洗衣废水（LWW）中NPEO和COD的降解。UF用于去除悬浮固体，而可溶性COD(COD0=239±6毫克。L-1)和NPEO(NPEO0=341±8μg。L-1)通过EO工艺氧化。不同的操作参数进行了研究，如电流密度，电解时间，阴极和支持电解质浓度的类型。使用实验设计方法，记录了COD和NPEO3-17降解的最佳条件。这包括实现97%的NPEO3-17降解和61%的COD降解，总运营成本为3.65美元·m-3。使用石墨阴极在4g·Na2SO4L-1存在下，在15mA·cm-2的电流密度下记录了这些最佳条件，反应时间为120分钟。EO工艺允许达到水回用所需的准则(NPEO<200μg。L-1，COD<100mg·L-1）。此外，我们的结果表明，NP和NPEO化合物，包括较高和较短的乙氧基化链（NPEO3-17），在EO过程中有效降解，去除率在94%至98%之间。这证实了EO过程有效降解NP的能力，NPEO分解的副产品。
