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The outbreaks of cyanobacterial blooms have caused severe threat to aquatic ecosystem and public health. In this work, electrochemical technology with RuO 2 /IrO 2 /Ti (RIT) or/and Al as anode for cyanobacterial bloom control and simultaneous water purification were studied. Compared with RIT-Al and Al electrodes, RIT exhibited the highest effects on bloom algae inactivation and inhibition of algae regrowth. Live/dead analysis, SEM, intracellular reactive oxygen species (ROS) and antioxidant system activities revealed that RIT could disintegrate bloom flocs and damage embedded algal cells due to high intensity of oxidation. With the lysis of cyanobacterial bloom, high content of intracellular compounds containing organic carbon, nitrogen and phosphorus released, necessitating water quality restoration. In the subsequent water purification process, RIT-Al overtook RIT and Al in removal of organic and nutrient pollutants due to the complex effects of electro-oxidation, coagulation, co-precipitation, electro-nitrification and electro-denitrification. Therefore, sequential electro-oxidation and electro-oxidation-coagulation process was an effective method for control cyanobacteria bloom and simultaneous removal of DOM, microcystin-LR (MC-LR), nitrogen and phosphorus, which is a promising technology. [Display omitted] • A sequential EO and EO-EC process were fabricated for efficient cyanobacteria bloom control and nutrient removal. • EO remove cyanobacterial bloom via floc disintegration, intracellular ROS formation and cell damage. • Cyanobacterial bloom disintegration by EO caused release of intracellular SCOD, TN and TP. • Nutrient was removed by electro-oxidation, coagulation, precipitation, nitrification and denitrification. [ABSTRACT FROM AUTHOR]

This study presents an integrated Electro-Oxidation/Electro-Coagulation/Electro-Reduction (EO/EC/ER) process for tertiary landfill leachate treatment. The influence of variables including leachate characteristics and operation conditions on the performance of EO/EC/ER process was evaluated. The removal mechanisms were explored by comparing results of anode, cathode, and bipolar electrode substitution experiments. The performance of the process in a scaled-up reactor was investigated to assure the feasibility of the process. Results showed that simultaneous removal of carbonaceous and nitrogenous pollutants was achieved under optimal conditions. Ammonia removal was due to the free chlorine generation of EO while organic matter degradation was achieved by both EO and EC processes. Nitrate removal was attributed to both ER and EC processes, with the higher removal achieved by ER process. In a scaled-up reactor, the EO/EC/ER process was able to remove 50–60% organic matter and 100% ammonia at charge of 1.5 Ah/L with energy consumption of 15 kW h/m 3 . Considering energy cost, the process is more efficient to meet the requirement of organic removal efficiency less than 70%. These results show the feasibility and potential of the EO/EC/ER process as an alternative tertiary treatment to achieve the simultaneous removal of organic matter, ammonia, nitrate, and color of leachate. [ABSTRACT FROM AUTHOR]

Abstract: An electrochemical reactor was built and used to remove arsenite from water. In this reactor, arsenite can be oxidized into arsenate, which was removed by electro-coagulation process simultaneously. The reactor mainly included dimension stable anode (DSA) and iron plate electrode. Oxidation of arsenite will occur at the DSA electrode in the electrochemical process. Meantime, the iron ions can be generated by the electro-induced process and iron oxides will form. Thus, the arsenic was removed by coagulation process. Influencing factors on the removal of arsenite were investigated. It is found that Ca2+ and Mg2+ ions promoted the removal of arsenite. However, Cl−, CO3 2−, SiO3 2−, and PO4 3− ions inhibited the arsenic removal. And, it is observed that the inhibition effect was the largest in the presence of PO4 3−. Furthermore, it is observed that the removal efficiency of arsenate is the largest in the pH value of 8. Increase or decrease of pH value did not benefit to the arsenite removal. Fourier transform infrared spectra were used to analyze the floc particles, it is suggested that the removal mechanism of As(III) in this system seems to be oxidative of As(III) to As(V) and to be removed by adsorption/complexation with metal hydroxides generated in the process. [ABSTRACT FROM AUTHOR]

Abstract: In this study the pollutant removal from a textile dyeing wastewater has been investigated by using the electro-coagulation technique with iron electrodes. In order to obtain optimal values of the system state variables, a 33 full factorial experimental design was applied. The electro-coagulation (EC) process response was evaluated on the basis of COD removal and decolourisation values. The electrolysis time and density current were statistically significant for the COD removal and decolourisation. Based on the lettuce seeds (Lactuca sativa) and brine shrimp (Artemia salina), the lowest toxicity level was achieved in 5min of electrolysis time. Due to the remaining high toxicity level above 30min of electrolysis time, the EC process is not adequate to be used in a single effluent treatment, suggesting that this electrochemical process of up to 5min could be used as part of a complete effluent treatment system. [Copyright &y& Elsevier]

The effect of different physicochemical treatments on the aerobic biodegradability of an industrial wastewater resulting from a cosmetic industry has been investigated. This industrial wastewater contains 11423 and 3148mgL−1 of chemical oxygen demand (COD) and anionic surfactants, respectively. The concentration of COD and anionic surfactants were followed throughout the diverse physicochemical treatments and biodegradation experiments. Different pretreatments of this industrial wastewater using chemical flocculation process with lime and aluminium sulphate (alum), and also advanced oxidation process (electro-coagulation (Fe and Al) and electro-Fenton) led to important COD and anionic surfactants removals. The best results were obtained using electro-Fenton process, exceeding 98 and 80% of anionic surfactants and COD removals, respectively. The biological treatment by an isolated strain Citrobacter braakii of the surfactant wastewater, as well as the pretreated wastewater by the various physicochemical processes used in this study showed that the best results were obtained with electro-Fenton pretreated wastewater. The characterization of the treated surfactant wastewater by the integrated process (electro-coagulation or electro-Fenton)-biological showed that it respects Tunisian discharge standards. [Copyright &y& Elsevier]

In this study, the effects of various operating conditions such as treatment time, DC current, initial pH, initial H2O2 concentration and distance between the electrodes on treatability of landfill leachate by using electro-Fenton (EF) method were examined. The settling characteristics of waste sludge produced from the treatment were also determined. According to the results, EF method can be used efficiently for the treatment of landfill leachate by using the proper operating conditions. The best removal efficiencies were obtained when: treatment duration is 20min, constant DC current value is 3A, H2O2 concentration is 2000mgL−1 and the initial pH value is 3. For these conditions, 72% COD, 90% color, 87% PO4-P and 28% NH4-N removals were obtained. It was also observed that using electrode distance between 1.8cm and 2.8cm increases efficiency of the COD removal, significantly. Sedimentation characteristics of the waste sludge produced from the EF method is fairly good. [Copyright &y& Elsevier]

Abstract: Liquid–liquid extraction was used in order to recover phenolic compounds from centrifuged olive mill wastewater (OMW), a polluting by-product of olive oil production process, and to reduce their toxicity for a subsequent aerobic or anaerobic digestion. Phenolic compounds were identified in untreated and treated OMW by gas chromatography coupled to mass spectrometry (GC–MS). The experimental results of ethyl acetate extraction showed that the monomers recovery efficiency was over 90%. This pre-treatment resulted in the removal of the major LMM phenolic compounds and a small part of HMM polyphenols. The aerobic treatment of the exhausted OMW fraction removed 78.7% of the soluble COD. In the case of anaerobic digestion at OLR ranged from 1 to 3.5gCODl−1 day−1, methanisation process exhibited high methane yield as 0.3l CH4 produced per g COD introduced and high COD removal (80%). However, a disruption of the process was observed when the OLR was increased to 4.5gCODl−1 day−1. A pre-treatment by electro-coagulation resulted in decreasing the toxicity and enhancing the performance of methanisation operated at higher OLR from 4 to 7.5gCODl−1 day−1. [Copyright &y& Elsevier]

The new catalytic decoloration of C. I. Acid Red 3R with electro-coagulation (EC) method assisted by cobalt phosphomolybdate modified kaolin has been studied. The result showed that this process could effectively remove the C. I. Acid Red 3R contained in wastewater and its color removal efficiency could reach up to 98. 3% in 7min. The kinetics of the catalytic decolorization of Acid Red 3R was also studied. The decolorization reaction order was dependent on the initial concentration [R]0 with respect to the concentration of C. I. Acid Red 3R. At lower [R]0 the order was first, which then decreases with increasing [R]0. The operating parameters such as initial pH, current density and temperature were also investigated. A possible reaction mechanism was proposed. [Copyright &y& Elsevier]

The aim of this paper was to investigate the feasibility of the removal of phosphate from aqueous solution by electro-coagulation (EC). The current density (CD) between 2.5 and 10 mA cm−2 and duration in the limits of 5–20 min were tried for different concentrations. In order to determine optimal operating conditions, the EC process used for the phosphate removal was examined in dependence with the CD, initial concentrations and time. The results of the experimental batch processing showed high effectiveness of the EC method in removing phosphate from aqueous solutions. [Copyright &y& Elsevier]