Disinfection By-products Research Articles

Sulfonamide disinfection byproducts exhibited severe toxicity to human commensal bacteria

Many antibiotic disinfection byproducts have been detected but their toxicity has not been evaluated adequately. In this report, the chlorination reaction kinetics of five common sulfamides (SAs), reaction intermediates and their toxicity were investigated. Chlorination of sulfapyridine (SPD), sulfamethazine (SMT), sulfathiazole (STZ), and sulfisoxazole (SIZ) followed the second-order kinetics, and were degraded completely within 10 min. A large number of reaction intermediates were deteced by LC-MS, among which a total of 16 intermediates were detected for the first time. Toxicity of the five SAs chlorination solutions was evaluated separately by examining their effects on the growth rate of S. salivarius K12, a commensal bacterium in the human digestive system. After 30 min chlorination, solutions of SMT, STZ and sulfadiazine (SDZ) each exhibited severe toxicity by inhibiting the bacteria growth completely, whereas the inhibition was only 50 % and 20 % by SIZ and SPD respectively. Based on the comparison between toxicity test results and mass spectra, three SA chlorination intermediates, m/z 187.2 (C10H10N4), m/z 287.2 (C9H7N3O4S2) and m/z 215 (C7H10N4O2S/C12H14N4) were proposed to be the primary toxicants in the chlorination products. Our study demonstrated the power of combined approach of chemical analysis and toxicity testing in identifying toxic disinfection byproducts, and highlighted the ne ed for more research on the toxicity evaluation and risk assessment of antibiotic disinfection byproducts.

Degradation of prometryn during UV/persulfate process: Kinetics and disinfection by-product formation

Prometryn is one of the commonly used triazine herbicides and is also widely used for algae removal in aquaculture. This study investigated the degradation kinetics of prometryn via UV/persulfate (PS) oxidation and confirmed its adherence to pseudo-first-order kinetics, with a calculated rate constant (kobs) of 0.2358 min−1. The impact of PS concentration, water matrix (including background ions of Cl− and Br− and natural organic matter (NOM)), and solution pH on prometryn degradation were assessed. Results indicated an increase in prometryn degradation with raising concentrations of PS, Cl−, and Br−, especially evident at a PS concentration of 400 μm where complete degradation was achieved. Conversely, degradation decreased with increasing NOM concentration and pH. Radical scavenging experiments affirmed the promotion of prometryn degradation in UV/PS by both HO• and SO4−•, with SO4−• contributing over 70 % of the total free radical contribution. Evaluation of disinfection by-product (DBP) formation revealed trichloromethane (TCM) as the predominant DBP in non‑bromine water and tribromomethane (TBM) in bromine water. Thus, this study offers a theoretical foundation for UV/PS degradation of triazine herbicides in aqueous environments. The obtained results hold significance for controlling DBPs in subsequent water treatment processes, ensuring the provision of safe drinking water to the public and meeting the sustainable development goal 6.

A Delicate Balance: Water Disinfection and By-Product Immunotoxicity.

Mouse macrophages and human blood cells exposed to very high levels of three trihalophenols showed changes in RNA methylation, pointing to one mechanism by which disinfection by-products may harm health, even as disinfection protects it in other ways.

Cytotoxicity of emerging halophenylacetamide disinfection byproducts in drinking water: Mechanism and prediction

Halophenylacetamides (HPAcAms) have been identified as a new group of nitrogenous aromatic disinfection byproducts (DBPs) in drinking water, but the toxicity mechanisms associated with HPAcAms remain almost completely unknown. In this work, the cytotoxicity of HPAcAms in human hepatoma (HepG2) cells was evaluated, intracellular oxidative stress/damage levels were analyzed, their binding interactions with antioxidative enzyme were explored, and a quantitative structure-activity relationship (QSAR) model was established. Results indicated that the EC50 values of HPAcAms ranged from 2353 μM to 9780 μM, and the isomeric structure as well as the type and number of halogen substitutions could obviously induce the change in the cytotoxicity of HPAcAms. Upon exposure to 2-(3,4-dichlorophenyl)acetamide (3,4-DCPAcAm), various important biomarkers linked to oxidative stress and damage, such as reactive oxygen species, 8‑hydroxy-2-deoxyguanosine, and cell apoptosis, exhibited a significant increase in a dose-dependent manner. Moreover, 3,4-DCPAcAm could directly bind with Cu/Zn-superoxide dismutase and induce the alterations in the structure and activity, and the formation of complexes was predominantly influenced by the van der Waals force and hydrogen bonding. The QSAR model supported that the nucleophilic reactivity as well as the molecular compactness might be highly important in their cytotoxicity mechanisms in HepG2 cells, and 2-(2,4-dibromophenyl)acetamide and 2-(3,4-dibromophenyl)acetamide deserved particular attention in future studies due to the relatively higher predicted cytotoxicity. This study provided the first comprehensive investigation on the cytotoxicity mechanisms of HPAcAm DBPs.

Algal-Rich Drinking Source Water: Effects of Chlorine Pre-oxidation on Algal Growth, Algal Organic Matter, and the Potential of Disinfection By-Products

Algal-Rich Drinking Source Water: Effects of Chlorine Pre-oxidation on Algal Growth, Algal Organic Matter, and the Potential of Disinfection By-Products

Selection of membrane for production of drinking water from surface and groundwater by nanofiltration

The aim of the work was to select a nanofiltration membrane that would ensure effective simultaneous co-removal of pollutants present in surface and groundwater, including contaminants such as bisphenol A and PFAS compounds. Series of membrane filtrations was carried out using 12 commercial nanofiltration membranes (NFX, NFG, NF270, NF90, DK, DL, TS80, SB90, TS40, XN45, NPO30, NPO10) under various operating parameters. The conducted tests showed that among tested membranes the membrane most suitable for the production of drinking water from model waters is the NF90 membrane by Dow Filmtec. Regardless of the composition of the water, its pH and transmembrane pressure, the water produced using NF90 membrane each time met the legal requirements in terms of heavy metals (chromium total, silver, nickel, lead, arsenic), iron, manganese, sulfates, chlorides, fluorides, nitrates, sodium, PFAS, tetrachlorethylene, bisphenol A and KMnO4 index. In addition, tests carried out to verify the susceptibility of the produced water to the formation of disinfection by-products (DBP - ∑THM and halogenoacetic acids) showed that DBP concentrations in produced water did not exceed the values permitted by law.

Using transcriptome analysis to reveal the effects of bromoacetamide at drinking water ambient concentrations on the transformation of eDNA carrying ARGs

Antibiotic resistance genes (ARGs) are frequently detected in drinking water. Transformation of extracellular antibiotic resistance genes (eARGs) is an important pathway for horizontal gene transfer, which facilitates the spread of ARGs among different species. Although most studies have pointed out that the presence of some common carbon-containing disinfection by-products, such as trihalomethanes, can increase the frequency of transformation by increasing the content of reactive oxygen species (ROS), nitrogen-containing disinfection by-products (N-DBPs), such as bromoacetamide (BAcAm), can also induce bacterial resistance to antibiotics by stimulating ROS. However, it is unclear whether such N-DBPs can similarly promote the transformation of ARGs in bacteria. In this study, the effect of BAcAm on the transformation of eDNA carrying ARGs was investigated, and found that DNA integration and repair (ruv, rec), efflux pumps (emr), and genes related to membrane proteins (bam, opm) were up-regulated in E. coli after addition of BAcAm. Furthermore, in addition to analyzing common functional genes, in terms of metabolic gene expression, which is usually overlooked, the genes related to amino acid biosynthesis (pot, arg, lys) were up-regulated while genes related to sulfur metabolism, which has a higher metabolic cost (thi, sssu) were down-regulated, which suggests that E. coli is able to effectively defend itself against the threat posed by BAcAm to its survival. In conclusion, the factors affecting the conversion of eDNA carrying ARGs into E. coli cells by BAcAm were suggested and elaborated that E. coli carrying ARGs can adapt to various unfavorable environments by regulating relevant metabolic mechanisms and survive in drinking water environment for a long period of time.

Degradation Strategy and Mechanism of Nitrogenous Disinfection By-products in Three-dimensional Electrochemical System

Nitrosopyrrolidine (NPYR) is a nitrogenous disinfection by-products (N-DBPs) that has attracted much attention due to its high toxicity and resistance to treatment. The removal of NPYR using a three-dimensional aerated electrochemical reactor (3DAER) was investigated. The artificial neural network (ANN) method was employed for the first time to optimize the operating parameters of NPYR degradation with the 3DAER system. Compared to manual parameter optimization, the NPYR degradation parameters generated with the ANN increased the degradation rate by 8.20% to 86.67%. The inhibition rate of the treated water sample used to treat luminescent bacteria was reduced by 49.16%. Mechanistic studies revealed that ·OH and ·O2- were involved in the reaction, and ·OH attacked nucleophilic sites and ·O2- targeted the electrophilic sites of NPYR. Gas chromatographymass spectrometry (GC–MS), combined with Fukui index analyses, was used to elucidate the pathway for NPYR degradation. This confirmed lower biological toxicities for the intermediate products formed during NPYR degradation. In conclusion, the MgFe-LDH/3DAER electrochemical process mitigated the environmental hazards associated with NPYR. This study offers theoretical insights and practical guidance for controlling water disinfection by-products.

Photothermal assisted space-confined chlorine activation for removal of pharmaceuticals and personal care products coupled with disinfection by-products control

The solar/chlorine process provides an energy-efficient technique for the abatement of some pharmaceuticals and personal care products (PPCPs) but it is inefficient in degrading PPCPs lacking electron-donating group and suffers high formation of disinfection byproducts (DBPs). In this study, a photothermal approach is developed to promote chlorine activation (photothermal/chlorine) under solar radiation to effectively remove a wide range of structurally diverse PPCPs and to control DBPs formation. To this end, a carbon black (CB) coated 3D porous melamine sponge (MS), namely CB@MS, is developed for the photothermal/chlorine application, achieving significantly enhanced PPCPs degradation with an ibuprofen (IBU) removal rate constant (0.22 min−1) 3.76 times that of the solar/chlorine process (0.058 min−1). Mechanistic investigations revealed that CB@MS confines the thermal energy within the 3D porous structure to achieve high localized heating for boosting PPCPs degradation in the confined space, which is equivalent to the thermal effect achieved by the solar/chlorine process at constant solution temperature of around 70 °C. Moreover, the photothermal/chlorine process reduces TOCl and DBPs formation by 77.6 % and 67.5 %, ascribed to adsorption by CB@MS, less chlorine exposure, and altered PPCPs degradation pathways. The broad applicability in various water matrices, and good reusability and stability of the photothermal/chlorine system also ensure its excellent practicality. This study offers in-depth mechanisms and practical insights into the development of a novel photothermal/chlorine process for PPCPs abatement and DBPs control.

Advances in understanding the reproductive toxicity of endocrine-disrupting chemicals in women.

Recently, there has been a noticeable increase in disorders of the female reproductive system, accompanied by a rise in adverse pregnancy outcomes. This trend is increasingly being linked to environmental pollution, particularly through the lens of Endocrine Disrupting Chemicals (EDCs). These external agents disrupt natural processes of hormones, including synthesis, metabolism, secretion, transport, binding, as well as elimination. These disruptions can significantly impair human reproductive functions. A wealth of animal studies and epidemiological research indicates that exposure to toxic environmental factors can interfere with the endocrine system's normal functioning, resulting in negative reproductive outcomes. However, the mechanisms of these adverse effects are largely unknown. This work reviews the reproductive toxicity of five major environmental EDCs-Bisphenol A (BPA), Phthalates (PAEs), Triclocarban Triclosan and Disinfection Byproducts (DBPs)-to lay a foundational theoretical basis for further toxicological study of EDCs. Additionally, it aims to spark advancements in the prevention and treatment of female reproductive toxicity caused by these chemicals.

Impact of climate change on formation of nitrogenous disinfection by-products. Part II: water blooming and enrichment by humic substances.

Climate change affects the concentration and characteristics of dissolved organic matter (DOM) in surface water. The changes in composition of DOM have many implications to drinking water quality, especially in the case of formation of disinfection by-products (DBPs). The aim of this study was to investigate the formation of nitrogenous DBPs (N-DBPs) during chlorination and chloramination, caused by the alternation of surface water's DOM driven by climate change. For this reason, two different cases were examined: (a) rise of algal organic matter (AOM) due to water blooming and (b) water enrichment by humic substances. The target compounds were haloacetonitriles (HANs), haloacetamides (HAcAms), and halonitromethane (TCNM). The results showed that Anabaena appears to be a major precursor for HAcAms and TCNM, while humic acids are precursors for HANs. The results of the mixtures presented the same pattern. During the water blooming case, HAcAms and TCNM formation are in favor, while during water enrichment by humic substances case, HANs is the N-DBP group with higher formation yield. Cloraminated samples presented higher values of cytotoxicity and genotoxicity compared to the chlorinated.

Computational-aided analysis of the pathway and mechanism of dichloroacetonitrile formation from phenylalanine upon chloramination

Dichloroacetonitrile (DCAN) is an emerging disinfection by-product (DBP) that is widespread in drinking water. However, the pathway for DCAN formation from aromatic amino acids remains unclear, leading to a lack of an understanding of its explicit fate during chloramination. In this study, we investigated the specific formation mechanism of DCAN during the chloramination of phenylalanine based on reaction kinetics and chemical thermodynamics. The reason for differences between aldehyde and decarboxylation pathways was explained, and kinetic parameters of the pathways were obtained through quantum chemistry calculations. The results showed that the reaction rate constant of the rate-limiting step of the aldehyde pathway with 1.9 × 10−11 s−1 was significantly higher than that of decarboxylation (3.6 × 10−16 s−1 M−1), suggesting that the aldehyde pathway is the main reaction pathway for DCAN formation during the chloramination of phenylalanine to produce DCAN. Subsequently, theoretical calculations were performed to elucidate the effect of pH on the formation mechanism, which aligned well with the experimental results. Dehydrohalogenation was found to be the rate-limiting step under acidic conditions with reaction rate constants higher than those of the rate-limiting step (expulsion of amines) under neutral conditions, increasing the rate of DCAN formation. This study highlights the differences in DCAN formation between the decarboxylation and aldehyde pathways during the chloramination of precursors at both molecular and kinetic levels, contributing to a comprehensive understanding of the reaction mechanisms by which aromatic free amino acids generate DCAN.

Phage cocktail superimposed disinfection: A ecological strategy for preventing pathogenic bacterial infections in dairy farms

Bovine mastitis (BM) is mainly caused by bacterial infection that has a highly impact on dairy production, affecting both economic viability and animal well-being. A cross-sectional study was conducted in dairy farms to investigate the prevalence and antimicrobial resistance patterns of bacterial pathogens associated with BM. The analysis revealed that Staphylococcus (49%), Escherichia (16%), Pseudomonas (11%), and Klebsiella (6%) were the primary bacterial pathogens associated with mastitis. A significant proportion of Staphylococcus strains displayed multiple drug resistance. The use of disinfectants is an important conventional measure to control the pathogenic bacteria in the environment. Bacteriophages (Phages), possessing antibacterial properties, are natural green and effective disinfectants. Moreover, they mitigate the risk of generating harmful disinfection byproducts, which are commonly associated with traditional disinfection methods. Based on the primary bacterial pathogens associated with mastitis in the investigation area, a phage cocktail, named SPBC-SJ, containing seven phages capable of lysing S. aureus, E. coli, and P. aeruginosa was formulated. SPBC-SJ exhibited superior bactericidal activity and catharsis effect on pollutants (glass surface) compared to chemical disinfectants. Clinical trials confirmed that the SPBC-SJ-based superimposed disinfection group (phage combined with chemical disinfectants) not only cut down the dosage of disinfectants used, but significantly reduced total bacterial counts on the ground and in the feeding trough of dairy farms. Furthermore, SPBC-SJ significantly reduced the abundance of Staphylococcus and Pseudomonas in the environment of the dairy farm. These findings suggest that phage-based superimposed disinfection is a promising alternative method to combat mastitis pathogens in dairy farms due to its highly efficient and environmentally-friendly properties.

Electrochemical reductive removal of trichloroacetic acids by a three-dimensional binderless carbon nanotubes/ CoP/Co foam electrode: Performance and mechanism

Numerous chlorinated disinfection by-products (DBPs) are produced during the chlorination disinfection of water. Among them, chloroacetic acids (CAAs) are of great concern due to their potential human carcinogenicity. In this study, effective electrocatalytic dechlorination of trichloroacetic acids (TCAA), a typical CAAs, was achieved in the electrochemical system with the three-dimensional (3D) self-supported CoP on cobalt foam modified by carbon nanotubes (CNT/CoP/CF) as the cathode. At a 10 mA cm−2 current density, 74.5% of TCAA (500 μg L−1) was converted into AA within 100 min. In-situ growth of CoP increased the effective electrochemical surface area of the electrode. Electrodeposited CNT promoted electron transfer from the electrode surface to TCAA. Therefore, the production of surface-adsorbed atomic hydrogen (H*) on CNT/CoP/CF was improved, further resulting in excellent electrochemical dechlorination of TCAA. The dechlorination pathway of TCAA proceeded into acetic acids via direct electronic transfer and H*-mediated reduction on CNT/CoP/CF electrode. Additionally, the electroreduction efficiency of CNT/CoP/CF for TCAA exceeded 81.22% even after 20 cycles. The highly efficient TCAA reduction performance (96.57%) in actual water revealed the potential applicability of CNT/CoP/CF in the complex water matrix. This study demonstrated that the CNT/CoP/CF is a promising non-noble metal cathode to remove chlorinated DBPs in practice.

Far-UVC Photolysis of Peroxydisulfate for Micropollutant Degradation in Water.

Increasing radical yields to reduce UV fluence requirement for achieving targeted removal of micropollutants in water would make UV-based advanced oxidation processes (AOPs) less energy demanding in the context of United Nations' Sustainable Development Goals and carbon neutrality. We herein demonstrate that, by switching the UV radiation source from conventional low-pressure UV at 254 nm (UV254) to emerging Far-UVC at 222 nm (UV222), the fluence-based concentration of HO• in the UV/peroxydisulfate (UV/PDS) AOP increases by 6.40, 2.89, and 6.00 times in deionized water, tap water, and surface water, respectively, with increases in the fluence-based concentration of SO4•- also by 5.06, 5.81, and 55.47 times, respectively. The enhancement to radical generation is confirmed using a kinetic model. The pseudo-first-order degradation rate constants of 16 micropollutants by the UV222/PDS AOP in surface water are predicted to be 1.94-13.71 times higher than those by the UV254/PDS AOP. Among the tested water matrix components, chloride and nitrate decrease SO4•- but increase HO• concentration in the UV222/PDS AOP. Compared to the UV254/PDS AOP, the UV222/PDS AOP decreases the formation potentials of carbonaceous disinfection byproducts (DBPs) but increases the formation potentials of nitrogenous DBPs.

Valorization of Field-Spent Granular Activated Carbon as Heterogeneous Ozonation Catalyst for Water Treatment.

Developing sustainable cost-effective strategies for valorization of field-spent granular activated carbon (s-GAC) from industrial water treatment has gained much interest. Here, we report a cost-effective strategy for the regeneration of s-GAC as an adsorbent in a large-scale drinking water treatment plant and used as an efficient and durable ozonation catalyst in water. To achieve this, a series of samples is prepared by subjecting s-GAC to thermally controlled combustion treatments with and without pyrolysis. The catalytic performance of the optimized sample is evaluated for oxalic acid degradation as the model pollutant under batch (>15 h) and continuous flow operations (>200 h). The partially deactivated catalyst upon reuse is restored by thermal treatment. Electron paramagnetic resonance and selective quenching experiments show the formation of singlet oxygen (1O2) during catalytic ozonation. The GAC-ozonation catalyst is efficient to minimize the formation of chlorinated disinfection by-products like trihalomethanes and haloacetic acids in an urban wastewater effluent.

Enhanced degradation of nitrogen-containing disinfection by-products via radical attack in ZnAl particle electrode system: Mechanism and density functional theory calculations

Disinfection by-products (DBPs), in water receive attention because of their toxicity, mutagenicity and carcinogenicity. In this study, Nitrosopyrrolidine (NPYR) in water is electrocatalytically degraded by using ZnAl layered double hydroxide/activated carbon (ZnAl-LDH/AC) as a particle electrode in a three-dimensional electrode reactor (3DER). The results of SEM, TEM and XRD showed the successful synthesis of ZnAl-LDH, in which Zn2Al1-LDH had regular morphology and better crystallinity. The results of electrochemical characterization tests indirectly showed that Zn2Al1-LDH/AC had the largest OPE, the smallest mass transfer resistance, and higher mass transfer rate, and better electrocatalytic performance. The pollutant concentration had the greatest effect on the removal rate of NPYR in the one-way experiment, and the interaction effect between different influencing factors is determined by response surface optimization experiments. The optimal operating conditions showed a pollutant removal rate of 83.78%. A response surface prediction model is constructed. Hydroxyl radicals and superoxide radicals are demonstrated to be the main contributors to indirect oxidation by free radical quenching experiments and EPR. DFT calculations combined with GC-MS and LC-MS results deduced two possible degradation pathways. Toxicity prediction of NPYR and its intermediates is performed using software. Based on the above study, a mechanism for the degradation of NPYR by 3DER is proposed.

Application and environmental impact of loose nanofiltration in surface water treatment

Loose nanofiltration (LNF) membranes with a molecular weight cutoff (MWCO) of about 1000 Da have great potential for high selectivity between natural organic matter (NOM) and mineral salts. Therefore, they are interesting for treatment plants for purifying oligotrophic lake waters with an elevated NOM concentration. This study was conducted to determine the design and operational expenses as well as the environmental impact of an LNF-based drinking water treatment process that removes NOM from Finnish surface water. Two LNF membranes with similar MWCOs were selected, and the results were compared to ultrafiltration, nanofiltration, and conventional treatment. One LNF membrane demonstrated a rejection rate of NOM higher than 95 % and a low rejection rate of hardness at about 40 %, while the other LNF membrane performed similarly to an ultrafiltration membrane. The LNF-based treatment process would increase operational expenses by 53—69 % but at the same time decrease the environmental impact by >18 %. Improved removal of aromaticity and low molecular weight compounds could lower the disinfection byproduct formation potential and microbial growth in the network, thus reducing the required chlorine dosage in the network and possibly bringing further cost savings.

Regression model and pathways of halonitromethane formation from amino acids in the presence of bromide ion under UV/monochloramine disinfection

Halonitromethanes (HNMs) including chlorinated and brominated HNMs, a category of nitrogenous disinfection by-products with high toxicity, were formed from amino acids (AAs) in the presence of bromide ion (Br-) under UV/monochloramine (UV/NH2Cl) disinfection. This study developed a regression model using water characteristics (pH, HCO3– and Br-) and disinfection conditions (disinfection time and NH2Cl doses) to predict HNM formation from AAs (tyrosine (Tyr), tryptophan (Trp) and aspartic acid (Asp)) in the presence of Br- under UV/NH2Cl disinfection. Main contributors to the abatement of Tyr and Trp were UV (6.1%-18.7%), HO (18.5%-62.3%), Cl2− (0.3%-17.9%), Br (2.4%-41.3%, kBr•,AA=∼109-1010 M−1·s−1), Br2− (1.3%-11.0%, kBr2•-,AA=∼108-109 M−1·s−1), NO (2.6%-43.0%) and CO3− (0%-43.2%) based on the first-principle kinetic model of UV/NH2Cl/Br- process, while the removal ratio of Asp was low. It was responsible for higher HNM concentrations from Tyr and Trp than those from Asp. Due to the decline in HNM concentrations with prolongation of reaction time, HNM concentrations were considered as the quadratic function of disinfection time with coefficients related to water characteristics and NH2Cl doses. The regression model with backward stepwise regression described HNM formation well. After introducing specific UV absorbance at 254 nm (SUVA254) and interaction terms associated with SUVA254, HNM formation from three AAs was successfully predicted by one regression equation (R2 = 0.91, mean absolute error = 0.46, mean relative error = 37%, root-mean-square error = 0.81). Using the optimal regression model, increasing NH2Cl doses was found to advance the peak time for HNM formation. Besides, obtained heatmaps of HNM formation revealed that a high NH2Cl dose with a high UV dose or low NH2Cl dose helped to limit HNM formation. Lastly, the possible formation pathways of HNMs were presented.

A novel NiFe-LDH/AC three-dimensional particle electrode system and its application for degradation of N-nitrosamines: Condition optimization and degradation mechanism

A green and sustainable three-dimensional particle electrodes system with nickel-iron layered double hydroxide mixing activated carbon particles (NiFe-LDH/AC) as particle electrodes is used in this work. Its employment in degradation of N-Nitrosodiethylamine (NDEA), A type of nitrosamines disinfection byproducts (NAs) widely present in water bodies, exhibiting significant degradation efficiency at close to neutral pH. Response surface methodology (RSM) is used to analyze the interaction effects and predict optimal conditions of four operating parameters (influent water flow, electrolyte concentration, current density and initial concentration) on the NDEA degradation efficiency. Calculated coefficients of determination (R2) are higher than 0.997 for all responses according to analysis of variance. At optimum conditions, a maximum degradation efficiency of 71.88% is achieved for NDEA. The results of electron paramagnetic resonance (EPR) and free radical quenching experiments indicate that the degradation of NDEA in the 3D AER system is dominated by •OH. Furthermore, based on the recognition of main reaction intermediates by GC-MS and density functional theory (DFT), possible degradation pathway is proposed and toxicological evaluation of degradation products is made. Our research provides a promising alternative method for the efficient and environmentally friendly removal of NAs from water.