Electrochemical carbon-nanotube filter performance toward virus removal and inactivation in the presence of natural organic matter

The performance of an electrochemical multiwalled carbon nanotube (EC-MWNT) filter toward virus removal and inactivation in the presence of natural organic matter was systematically evaluated over a wide range of solution chemistries. Viral removal and inactivation were markedly enhanced by applying DC voltage in the presence of alginate and Suwannee River natural organic matter (SRNOM). Application of 2 or 3 V resulted in complete (5.8 to 7.4 log) removal and significant inactivation of MS2 viral particles in the presence of 5 mg L(-1) of SRNOM or 1 mg L(-1) of alginate. The EC-MWNT filter consistently maintained high performance over a wide range of solution pH and ionic strengths. The underlying mechanisms of enhanced viral removal and inactivation were further elucidated through EC-MWNT filtration experiments using carboxyl latex nanoparticles. We conclude that enhanced virus removal is attributed to the increased viral particle transport due to the applied external electric field and the attractive electrostatic interactions between the viral particles and the anodic MWNTs. The adsorbed viral particles on the MWNT surface are then inactivated through direct surface oxidation. Minimal fouling of the EC-MWNT filter was observed, even after 4-h filter runs with solutions containing 10 mg L(-1) of natural organic matter and 1 mM CaCl(2). Our results suggest that the EC-MWNT filter has a potential for use as a high performance point-of-use device for the removal of viruses from natural and contaminated waters with minimal power requirements.     

Electrochemical inactivation of triclosan with boron doped diamond film electrodes

This research investigated an electrochemical method for inactivating contaminated stockpiles of the biocidal agent, triclosan. The goal of the electrolysis was to produce products that were amenable to treatment in conventional activated sludge treatment systems. Triclosan oxidation in electrochemical cells with boron doped diamond (BDD) film anodes was investigated in aqueous solutions at a pH value of 12. Chronoamperometry experiments showed that direct oxidation of triclosan occurred at potentials below those for H2O, Cl-, or OH- oxidation. Measurable rates of triclosan oxidation began at potentials above 0.4 V with respect to the standard hydrogen electrode (SHE), while potentials of 0.5, 1.3, and 1.8 V were required to obtain measurable oxidation rates of H2O, Cl-, and OH-, respectively. At anode potentials below 2 V, the dominant electrode reaction involved direct triclosan oxidation, while indirect oxidation was the dominant pathway at higher potentials. However, cyclic voltammetry experiments showed that direct oxidation of triclosan resulted in the formation of a passivating film on the electrode that could only be removed by oxidation at potentials above 3 V. Direct triclosan oxidation showed a very weak potential dependence, suggesting that its oxidation was limited by chemical dependent factors rather than by an outer-sphere electron transfer reaction. Organic triclosan oxidation products consisted primarily of chlorinated acetic acids and chlorinated phenolic compounds. Although the byproducts of triclosan oxidation became increasingly less reactive with increasing electrolysis time, triclosan could be completely oxidized to CO2 at current densities above 2 mA/cm2. Microtox testing indicated that residual triclosan accounted for nearly all the toxicity in the treated water, despite the fact that chlorinated byproduct concentrations were significantly higher than those of triclosan itself.     

Multi-wall carbon nanotube film-based electrochemical sensor for rapid detection of Ponceau 4R and Allura Red

The monitoring of synthetic colourants in foods is very important due to their potential toxicity and pathogenicity. Herein, an electrochemical sensor for rapid and simple detection of Ponceau 4R and Allura Red was constructed using multi-wall carbon nanotube (MWNT) sensing film. In pH 7.0 phosphate buffer, two oxidation peaks are observed at 0.56 and 0.68 V for Ponceau 4R and Allura Red. Because of its large surface area and high accumulation efficiency, the MWNT film sensor remarkably enhances the oxidation signals of Ponceau 4R and Allura Red. The detection parameters such as pH value, amount of MWNT, accumulation potential and time were optimised. The MWNT film sensor possesses high sensitivity to Ponceau 4R and Allura Red, and the limits of detection are as low as 15 and 25 μg L⁻¹. Finally, the MWNT sensor was successfully used to detect Ponceau 4R and Allura Red in different soft drinks.     

Efficient electrochemical oxidation of perfluorooctanoate using a Ti/SnO2-Sb-Bi anode

The electrochemical decomposition of persistent perfluorooctanoate (PFOA) with a Ti/SnO2-Sb-Bi electrode was demonstrated in this study. After 2 h electrolysis, over 99% of PFOA (25 mL of 50 mg·L(-1)) was degraded with a first-order kinetic constant of 1.93 h(-1). The intermediate products including short-chain perfluorocarboxyl anions (CF3COO-, C2F5COO-, C3F7COO-, C4F9COO-, C5F11COO-, and C6F13COO-) and F- were detected in the aqueous solution. The electrochemical oxidation mechanism was revealed, that PFOA decomposition first occurred through a direct one electron transfer from the carboxyl group in PFOA to the anode at the potential of 3.37 V (vs saturated calomel electrode, SCE). After that, the PFOA radical was decarboxylated to form perfluoroheptyl radical which allowed a defluorination reaction between perfluoroheptyl radical and hydroxyl radical/O2. Electrospray ionization (ESI) mass spectrum further confirmed that the oxidation of PFOA on the Ti/SnO2-Sb-Bi electrode proceeded from the carboxyl group in PFOA rather than C-C cleavage, and the decomposition processes followed the CF2 unzipping cycle. The electrochemical technique with the Ti/SnO2-Sb-Bi electrode provided a potential method for PFOA degradation in the aqueous solution.     

纳米Fe2O3靶向鸡肉腐败菌光催化抑菌效能 特性研究

目的探索可见光下纳米Fe2O3对鸡肉腐败菌的光催化抑菌效能特性及机制。方法以Escherichia coli及鸡肉腐败菌Pseudomonas fluorescens和Macrococcus caseolyticus为受试菌株,可见光照为激发条件,研究纳米Fe2O3对细菌菌落数量和菌体脂质氧化程度的影响。结果纳米Fe2O3在可见光下能够有效抑制E.coli、P.fluorescens和M.caseolyticus生长繁殖,1.2 mmol/L的H2O2能够增强Fe2O3的光催化抑菌活性;当Fe2O3质量浓度为0.4 g/L时,对P.fluorescens和M.caseolyticus的抑菌作用效果最强;在光催化过程中,P.fluorescens和M.caseolyticu的脂质氧化值随着反应时间延长呈先升高后降低的趋势,在120 min分别达到最大值1.31nmol/mg(细胞干重)和2.14 nmol/mg(细胞干重)。结论可见光条件下,M.caseolyticus对光催化反应比P.fluorescens更加敏感,纳米Fe2O3先引起细菌体内脂质氧化,进而导致菌体细胞破裂而死亡。     

Control of aerosol contaminants in indoor air: combining the particle concentration reduction with microbial inactivation

An indoor air purification technique, which combines unipolar ion emission and photocatalytic oxidation (promoted by a specially designed RCI cell), was investigated in two test chambers, 2.75 m3 and 24.3 m3, using nonbiological and biological challenge aerosols. The reduction in particle concentration was measured size selectively in real-time, and the Air Cleaning Factor and the Clean Air Delivery Rate (CADR) were determined. While testing with virions and bacteria, bioaerosol samples were collected and analyzed, and the microorganism survival rate was determined as a function of exposure time. We observed that the aerosol concentration decreased approximately 10 to approximately 100 times more rapidly when the purifier operated as compared to the natural decay. The data suggest that the tested portable unit operating in approximately 25 m3 non-ventilated room is capable to provide CADR-values more than twice as great than the conventional closed-loop HVAC system with a rating 8 filter. The particle removal occurred due to unipolar ion emission, while the inactivation of viable airborne microorganisms was associated with photocatalytic oxidation. Approximately 90% of initially viable MS2 viruses were inactivated resulting from 10 to 60 min exposure to the photocatalytic oxidation. Approximately 75% of viable B. subtilis spores were inactivated in 10 min, and about 90% or greater after 30 min. The biological and chemical mechanisms that led to the inactivation of stress-resistant airborne viruses and bacterial spores were reviewed.     

Rapid detection of enterotoxigenic Escherichia coli O6 in water by using monoclonal antibody and a photon-counting television camera

Monoclonal antibodies (MAbs) raised against Escherichia coli O6:H16 were screened against 15 strains of E. coli and 19 non-E. coli bacteria. A MAb-luminescence assay using MAb-5.8, which shows no cross-reactions with non-E. coli bacteria, and a photon-counting television camera were developed for rapid enumeration of E. coli O6:H16 in water. The membrane filter that retained bacteria was boiled for 5 min in a buffer and incubated with biotinylated MAb-5.8. After incubation with streptavidin-peroxidase conjugate, it was reacted with luminol-based reaction mixture. Luminous image and light intensity of the filter was recorded with a Biocell Counter. Levels of E. coli O6 higher than 7 x 10(3) CFU were detected by the MAb-luminescence assay when E. coli O6 was spotted onto the membrane filter. The sample that contained E. coli O6:H16 was filtered through a membrane filter, and the filter that retained bacteria was incubated on a filter paper soaked with nutrient broth supplemented with 0.5% NaCl at 37 degrees C for 6 h. The number of light emission points on the filter correlated well with initial E. coli O6:H16 counts within the range of 1 to 3 x 10(2) CFU. The correlation coefficient was 0.89.     

臭氧水与副干酪乳杆菌Z21联合处理对绿豆芽中大肠杆菌O157:H7的抑制机制

为研究臭氧水联合副干酪乳杆菌Z21发酵上清液对绿豆芽中大肠杆菌O157:H7的杀菌效果、细胞结构影响和生物膜清除作用,本实验对人工污染大肠杆菌O157:H7的绿豆芽进行联合处理,选出最优的杀菌条件,采用流式细胞仪、扫描电镜、傅里叶红外光谱（Fourier-transform infrared spectroscopy,FT-IR）、拉曼光谱分析臭氧水联合Z21发酵上清液的杀菌机制;通过菌落计数及胞外聚合物分析,研究了臭氧水联合Z21发酵上清液对大肠杆菌O157:H7生物膜的清除效果。结果表明,1.5 mg/L臭氧水联合10%（v/v）Z21发酵上清液处理对大肠杆菌O157:H7杀菌效果最佳,菌落总数减少了2.81 lg CFU/g;与对照组相比,联合处理破坏了大肠杆菌O157:H7细胞壁和细胞膜中的多糖,脂质和蛋白质结构,增加了细胞膜的通透性,改变了菌体形态。联合处理对生物膜有良好的清除效果,显著降低了生物膜的胞外聚合物含量（P<0.05）。本研究为大肠杆菌生物膜的清除及农产品防腐保鲜提供了理论依据。     

Electrochemical sensor for hazardous food colourant quinoline yellow based on carbon nanotube-modified electrode

A novel electrochemical method using multi-wall carbon nanotube (MWNT) film-modified electrode was developed for the detection of quinoline yellow. In pH 8 phosphate buffer, an irreversible oxidation peak at 0.71 V was observed for quinoline yellow. Compared with the unmodified electrode, the MWNT film-modified electrode greatly increases the oxidation peak current of quinoline yellow, showing notable enhancement effect. The effects of pH value, amount of MWNT, accumulation potential and time were studied on the oxidation peak current of quinoline yellow. The linear range is from 0.75 to 20 mg L⁻¹, and the limit of detection is 0.5 mg L⁻¹. It was applied to the detection of quinoline yellow in commercial soft drinks, and the results consisted with the value that obtained by high-performance liquid chromatography.     

乳酸链球菌素(Nisin)与超高压结合对E.coli的协同杀菌效应

本文探究了乳酸链球菌素(Nisin)与超高压(High pressure processing,HPP)结合处理对E.coli O157:H7产生的协同杀菌效果,并分析其协同作用机制。以革兰氏阴性菌E.coli为目标菌,用0.005%或0.01% Nisin结合350 MPa/2 min超高压处理,通过扫描电镜和透射电镜分别观察E.coli细胞外部形态与内部结构、激光共聚焦显微镜与流式细胞仪检测细胞膜通透性。结果表明,与单独超高压处理相比,0.005%或0.01% Nisin结合350 MPa/2 min超高压对E.coli具有明显协同杀菌效果,E.coli菌落数下降6~8个数量级,细胞外形变化不明显,但细胞膜和内部结构受到了更严重的破坏,细胞膜完整的细菌仅占总数的2.13%~5.68%,细胞发生更多内溶物外泄和出现更多的空腔。因此,Nisin和HPP存在协同杀菌机制,推测HPP首先破坏E.coli细胞外膜,Nisin作用于外膜受损的细胞进而破坏细胞膜,细胞内溶物外泄形成空腔,从而导致细胞死亡。     

Effect of surface roughness on inactivation of Escherichia coli O157:H7 87-23 by new organic acid-surfactant combinations on alfalfa, broccoli, and radish seeds

Surface roughness has been reported as one of the factors affecting microbial attachment and removal. Seed surfaces are complex, and different seed varieties have different surface topographies. As a result, a sanitizer effective in eliminating pathogenic bacteria on one seed may not be as effective when applied to another seed. The objectives of this research were (i) to investigate the efficacy of malic acid and thiamine dilaurylsulfate (TDS) combined treatments for inactivation of E. coli O157:H7 strain 87-23 on alfalfa, broccoli, and radish seeds, (ii) to quantify surface roughness of the seeds, and (iii) to determine the correlation between microbial removal and surface roughness. The surface roughness of each seed type was measured by confocal laser scanning microscopy (CLSM) and surface profilometry. Surface roughness (Ra) values of the seeds were then calculated from CLSM data. Seeds inoculated with E. coli O157:H7 87-23 were washed for 20 min in malic acid and TDS solutions and rinsed for 10 min in tap water. Radish seeds had the highest Ra values, followed by broccoli and alfalfa seeds. A combination of 10% malic acid and 1% TDS was more effective than 20,000 ppm of Ca(OCl)(2) for inactivation of E. coli O157:H7 87-23 on broccoli seeds, while the inactivation on radish and alfalfa seeds was not significantly different compared with the 20,000-ppm Ca(OCl)(2) wash. Overall, a negative correlation existed between the seeds' Ra values and microbial removal. Different seeds had different surface roughness, contributing to discrepancies in the ability of the sanitizers to eliminate E. coli O157:H7 87-23 on the seeds. Therefore, the effectiveness of one sanitizer on one seed type should not be translated to all seed varieties.     

Review of factors affecting microbial survival in groundwater

This review quantitatively examines a number of published studies that evaluated survival and inactivation of public-health-related microorganisms in groundwater. Information from reviewed literature is used to express microbial inactivation in terms of log10 decline per day for comparison to other studies and organisms. The geometric mean value for inactivation rates for coliphage, poliovirus, echovirus, coliform bacteria, enterococci, and Salmonella spp. were similar at approximately 0.07-0.1 log10 day(-1), while geometric mean inactivation rates for hepatitis A virus, coxsackievirus, and phage PRD-1 were somewhat less at 0.02-0.04 log10 day(-1). Viruses show a temperature dependency with greater inactivation at greater temperatures; however this occurs largely at temperatures greater than 20 degrees C. Coliform bacteria die off in groundwater does not show the temperature dependency that viruses show, likely indicating a complex interplay of inactivation and reproduction subject to influences from native groundwater organisms, temperature, and water chemistry. The presence of native microorganisms seems to negatively impact E. coli survival more so than viruses, but in most cases, nonsterile conditions led to a greater inactivation for viruses also. The effect of attachment to solid surfaces appears to be virus-type-dependent, with PRD-1 more rapidly inactivated as a result of attachment and hepatitis A and poliovirus survival prolonged when attached.     

The role of reactive oxygen species in the electrochemical inactivation of microorganisms

Electrochemical disinfection has emerged as one of the most promising alternatives to the conventional disinfection of water in many applications. Although the mechanism of electrochemical disinfection has been largely attributed to the action of electro-generated active chlorine, the role of other oxidants, such as the reactive oxygen species (ROS) *OH, O3, H2O2, and *O2- remains unclear. In this study, we examined the role of ROS in the electrochemical disinfection using a boron-doped diamond (BDD) electrode in a chloride-free phosphate buffer medium, in order to avoid any confusion caused by the generation of chlorine. To determine which species of ROS plays the major role in the inactivation, the effects of several operating factors, such as the presence of *OH scavenger, pH, temperature, and the initial population of microorganisms, were systematically investigated. This study clearly showed that the *OH is the major lethal species responsible for the E. coli inactivation in the chloride-free electrochemical disinfection process, and that the E. coli inactivation was highly promoted at a lower temperature, which was ascribed to the enhanced generation of O3.     

Role of hydroxyl radicals and mechanism of Escherichia coli inactivation on Ag/AgBr/TiO2 nanotube array electrode under visible light irradiation

A ternary Ag/AgBr/TiO(2) nanotube array electrode with enhanced visible-light activity was synthesized by a two-step approach including electrochemical process of anodization and an in situ photoassisted deposition strategy. The dramatically enhanced photoelectrocatalytic activity of the composite electrode was evaluated via the inactivation of Escherichia coli under visible light irradiation (λ>420 nm), whose performance of complete sterilization was much superior to other reference photocatalysts. PL, ESR, and radicals trapping studies revealed hydroxyl radicals were involved as the main active oxygen species in the photoelectrocatalytic reaction. The process of the damage of the cell wall and the cell membrane was directly observed by ESEM, TEM, and FTIR, as well as further confirmed by determination of potassium ion leakage from the killed bacteria. The present results pointed to oxidative attack from the exterior to the interior of the Escherichia coli by OH(?), O(2)(?-), holes and Br(0), causing the cell to die as the primary mechanism of photoelectrocatalytic inactivation.     

The lactoperoxidase system increases efficacy of high-pressure inactivation of foodborne bacteria

The inactivation of eight different bacteria comprising Escherichia coli LMM1010 and MG1655, respectively a pressure-resistant strain and the corresponding wild-type, Salmonella Typhimurium, Pseudomonas fluorescens, Staphylococcus aureus, Enterococcus faecalis, Listeria innocua and Lactobacillus plantarum, by high hydrostatic pressure in skim milk supplemented with the lactoperoxidase-hydrogen peroxide-thiocyanate (LP) system at naturally occurring concentration was studied. In the absence of pressure treatment, the LP system had either no effect, i.e. on S. Typhimurium and E. coli LMM1010, a growth inhibiting effect, i.e. on E. coli MG1655, L. innocua, S. aureus, L. plantarum and E. faecalis, or a bactericidal effect, i.e. on P. fluorescens. The presence of the LP system affected inactivation by high pressure in a cell density-dependent manner. At low cell concentration (10(6) cfu/ml), the LP system strongly increased high-pressure inactivation as measured immediately after pressure treatment of all bacteria except the pressure-resistant E. coli. At high cell density (10(9) cfu/ml), only inactivation of L. innocua, E. faecalis and L. plantarum were enhanced. For both E. coli strains, the fate of the bacteria during 24 h following pressure treatment was also studied. It was found that in the presence of the LP system, considerable further inactivation occurred in the first hours after pressure treatment. The potential of the LP system to improve the bactericidal efficiency of high-pressure treatment for food preservation is discussed.     

Temperature governs the inactivation rate of vegetative bacteria under growth-preventing conditions

Novel studies, in combination with a meta-analysis of available data, were undertaken to explore the kinetics of non-thermal inactivation of Escherichia coli with particular attention to inactivation in fermented meats and including analogous broth-based model systems. The analyses were based on rates of inactivation and specifically investigated the influence of temperature, pH and water activity at levels that alone, or in combination, prevented growth. When independently-derived inactivation data, obtained using different test conditions and diverse E. coli strains, were presented as Arrhenius plots, temperature was found to have a strong effect on the rate of inactivation, explaining 60% of the variance in the data. The slope of the Arrhenius plot changed, however, at temperatures above approximately 47 degrees C, corresponding to the maximum for growth of E. coli. A strong and consistent effect of pH or water activity on inactivation rate was not observed upon meta-analysis of collated data, but the relative effect of both factors was quantified in an analogous broth-based system. We also observed that inactivation rates of three strains of Listeria monocytogenes in the range 5 to 40 degrees C did not differ systematically from those of four strains of E. coli when growth was prevented by low pH and water activity. The observations of a consistent slope of Arrhenius plots for non-thermal inactivation rate of bacteria under diverse environmental conditions and for different strains and species, but which differ from slopes associated with thermal inactivation, raise the intriguing possibility of a mechanism of inactivation at sub-lethal temperatures, distinct from thermal inactivation, that is common to many vegetative bacteria.     

Ag沉积N、S掺杂改性P25材料对大肠杆菌的抑菌性研究

为扩展纳米TiO_2光谱响应范围,提高其可见光催化抗菌性能,本文以商业纳米TiO_2为原料,采用Ag化学沉积,N、S非金属元素掺杂制备改性P25抑菌材料(Ag-P25、Ag-N-P25、Ag-S-P25),研究这三种材料在可见光下对大肠杆菌的抑菌效果。研究表明,三种抑菌材料对大肠杆菌均有良好的抑制效果,其抑菌率随光照时间延长而不断上升。三种材料抑菌效果的强弱顺序为:Ag-S-P25、Ag-N-P25、Ag-P25。当光照时间为100min时,三者对大肠杆菌的抑菌率均达100%,与纯P25的抑菌率(79%)相对比,提高了21%。通过扫描电镜观察和提取菌体质粒DNA的电泳检测表明,三种材料对大肠杆菌菌体造成破坏,引起DNA泄漏,导致菌体死亡。通过研究讨论改性P25材料对大肠杆菌的灭活机理,可为具有抗菌功能的新型保鲜材料的研究开发提供理论和实验依据。     

Assessment of F-RNA Coliphage as a Potential Indicator of Enteric Virus Contamination of Hog Carcasses

Hepatitis E virus (HEV) is common in pigs, and some swine HEV strains are closely related to human strains. The zoonotic transmission of HEV is now well established. HEV can be detected by molecular techniques, but the significance of the presence of viral nucleic acid is questionable when foods are subjected to virus inactivation treatments. F-RNA coliphages are attractive candidates as indicators for enteric viruses because they are similar in size and survival characteristics and can be rapidly cultured. Information on the contamination of hog carcasses with enteric or hepatic viruses during slaughter is lacking. The objective of this study was to compare the incidence and levels of contamination of hog carcasses with F-RNA coliphages, HEV, total aerobic bacteria, coliforms, and Escherichia coli at different stages of the dressing process. Hog carcasses entering the commercial slaughter facility are heavily contaminated with F-RNA coliphages and HEV. Subsequent processes such as scalding, singing, and pasteurization can reduce the incidence and levels of F-RNA coliphages and HEV substantially to almost undetectable levels. Large discrepancies between the amount of viral nucleic acid and infectious F-RNA coliphage particles, both at high levels and low levels of contamination, were observed. The prevalence and levels of viable F-RNA coliphages were lower than those of total aerobic bacteria, coliforms, and E. coli in the anal area and on random sites before pasteurization. At a research abattoir, there was no overall mean reduction of viable F-RNA coliphages recovered from random sites before pasteurization and after washing, whereas overall mean reductions of 1.2, 2.6, and 2.9 log CFU for total aerobic bacteria, coliforms, and E. coli, respectively, were obtained. These findings suggest that bacteria such as coliforms and E. coli may not be suitable as indicators for enteric viruses in a meat processing environment.     

Anaerobic electrochemical corrosion of mild steel in the presence of extracellular polymeric substances produced by a culture enriched in sulfate-reducing bacteria

The corrosion of mild steel in a seawater medium containing extracellular polymeric substances (EPS) produced by sulfate-reducing bacteria (SRB) was studied by electrochemical experiments and atomic force microscopy (AFM). Under anaerobic conditions, the corrosion of mild steel increased up to 5-fold in the presence of a 1% (w/w) EPS solution but in the absence of SRB. The enhanced corrosion is mainly due to the oxidizing power of EPS with a reduction potential of E1/2 at -0.54 V (saturated calomel electrode), which is 0.4 V above that of hydrogen reduction. The electrochemical reduction of EPS provides a couple to iron oxidation, as demonstrated by H-shaped cell experiments in which the steel sample and EPS are not in physical contact but are ionically connected via the solution and electronically connected through an external wire. Fourier transformation infrared spectroscopy and X-ray photoelectron spectroscopy showed that EPS derived from SRB are comprised of 60% proteins, 37% polysaccharides, and 3% hydrocarbons. The XPS results showed that, upon corrosion, polysaccharide components were mostly converted to hydrocarbons.     

Electrochemical oxidation as a final treatment of synthetic tannery wastewater

Vegetable tannery wastewaters contain high concentrations of organics and other chemicals that inhibit the activity of microorganisms during biological oxidations, so biorefractory organics that are not removed by biological treatment must be eliminated by a tertiary or advanced wastewater treatment. In this paper, the applicability of electrochemical oxidation as a tertiary treatment of a vegetable tannery wastewater was investigated by performing galvanostatic electrolysis using lead dioxide (Ti/PbO2) and mixed titanium and ruthenium oxide (Ti/TiRuO2) as anodes under different experimental conditions. The experimental results showed that both the electrodes performed complete mineralization of the wastewater. In particular, the oxidation took place on the PbO2 anode by direct electron transfer and indirect oxidation mediated by active chlorine, while it occurred on the Ti/TiRuO2 anode only by indirect oxidation. Furthermore, the Ti/PbO2 gave a somewhat higher oxidation rate than that observed for the Ti/TiRuO2 anode. Although the Ti/TiRuO2 required almost the same energy consumption for complete COD removal, it was more stable and did not release toxic ions, so it was the best candidate for industrial applications. With the Ti/TiRuO2 anode, the rate of tannery wastewater oxidation increased with the current density, pH, and temperature of the solution. These results strongly indicate that electrochemical methods can be applied effectively as a final treatment of vegetable tannery wastewater allowing the complete removal of COD, tannin, and ammonium and decolorization.