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The electrolysis process adopting copper electrodes and ceramic membrane with pore sizes of 0.1-0.2 μm were consisted to a system for the treatment of sewage from decentralized small communities. The system was operated under an HRT of 0.1 hour, voltage of 24 V, and TMP of 0.05 MPa. The system showed average removals of organics, nitrogen, phosphorus, and solids of up to 80%, 52%, 92%, and 100%, respectively. Removal of organics and nitrogen dramatically increased in proportion to increment of influent loading. Phosphorus and solids were remarkably eliminated by both electro-coagulation and membrane filtration. The residual particulate constituents could also be removed successfully through membrane process. A system composed of electrolysis process with ceramic membrane would be a compact, reliable, and flexible option for the treatment of sewage from decentralized small communities.

The objective of this study was to determine the effectiveness of two-stage electro-coagulation (EC) process using multi-parameter optimization for treating bio-digested distillery spent wash by stainless steel (SS) and aluminum (Al) electrodes. Operating parameters have been optimized and treatment efficiency of SS and Al electrodes have been compared by central composite design of response surface analysis in terms of COD, color and total organic carbon (TOC) removal. Individual and interactive effects of four independent parameters namely initial pH (pHo: 2-10 and 4-10 for SS and Al electrodes, respectively), current density (j: 30.86-154.32 A m(-2)), inter-electrode distance (g: 0.5-2.5 cm) and electrolysis time (t: 30-150 min) on the COD, color and TOC removal efficiency were evaluated for both the electrodes. SS electrode was found to be more effective for the removal of COD, color and TOC with removal efficiencies of 70%, 93% and 72%, respectively, as compared to Al electrode, which showed respective removal efficiencies of 59%, 80% and 55%. A two-stage EC process was also conducted to study the predominance of different types of electrodes, and to increase the efficiency of EC process. Results shows that SS followed by Al electrode (with total COD, color and TOC removal efficiency of 81%, 94% and 78%, respectively) was found to be more effective than Al followed by SS electrode combination (with total COD, color and TOC removal efficiency of 78%, 89% and 76%, respectively). Present study shows that EC process can be used as an additional step to bio-methanation process so as to meet effluent discharge standards in distilleries.

To test the effect of electrolysis and microbial remediation technology in polluted river sediment, we explored the possibility of using electrolysis method to remove ammoniacal nitrogen–nitrogen (NH3–N), nitrate-nitrogen (NO3––N) and phosphate ions-phosphorous (PO43−–P). The electrolysis was carried out by double electrolysis reaction system with a pair of a titanium (Ti) mesh cathode, a Ti/Ti dioxide (TiO2)/Ruthenium (IV) oxide (RuO2) (RuO2–IrO2/Ti) mesh anode, and another pair of magnesium–aluminum (Mg–Al) alloy anode and a titanium mesh cathode placed within the sediment and overlying water. Results showed approximately 151.82 ± 21.69 mg total nitrogen (TN) in sediment was removed, which was five times than the non-electrolytic controls (30.21 ± 13.73 mg). Furthermore, NH3–N concentration in the sediment was substantially reduced (up to 2.9 times) compared to the non-electrolytic controls. Its efficiency lies in the electrolysis process, which may directly remove NH3–N through electrochemical oxidation and simultaneously produce oxygen which helps nitrifying bacteria to convert NH3–N into an NO3−–N by anode; moreover, electrolysis may directly remove NO3−–N in the overlying water through electrochemical reduction while simultaneously producing hydrogen electron donors for hydrogen autotrophic microorganisms, such as Hydrogenophohaga. This genus of hydrogen autotrophic denitrifying bacteria dominated the removal of NO3−–N by a cathode in electrolytic sediment. Electrolysis also reduced the PO43−–P through electro-coagulation since Mg2+ ions also produced a sacrificial Mg–Al alloy anode. This anode was used in conjunction with electro-deposition on a Ti mesh cathode to increase PO43−-P removal in the overlying water and sediment. This study verifies the benefits of electrolysis-driven bioremediation as a sustainable technology for the bioremediation of N and P polluted river sediment. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to investigate the electrochemical treatment of textile dye wastewater in the presence of NaCl electrolyte by using aluminium electrodes. Design/methodology/approach – The electrochemical treatment of textile dye wastewater was optimized using response surface methodology (RSM). RSM-based D-optimal design was employed to construct statistical models relating turbidity and designed effective parameters known as current density, electrolyte concentration and electrolysis time. The experimental plan consists of a three-factor (three numerical) matrix. Findings – The results show that the current density has significant effect on the reduction of turbidity. Besides, electrolysis time is the most influential factor on the turbidity. In order to enhance the electrochemical treatment performance, no coagulant addition or further physicochemical processes were employed. Originality/value – Industrial certain textile dye wastewater in Turkey is used to determine optimal values. [ABSTRACT FROM AUTHOR]

Abstract: In this study, treatment of textile printing dye-bath effluent (DBE) has been performed by electro-coagulation (EC) method using aluminum (Al) electrode in a batch mode. Various operating parameters such as initial pH (pHo ), current density (J), electrolysis time (t) and inter electrode distance (d) were varied so as to see their effect on multiple responses namely chemical oxygen demand (COD) removal (Y 1), color removal (Y 2) and specific energy consumed (kWh/kg of COD removed; Y 3). Full factorial central composite design (CCD) has been used for carrying out experiments and optimizing responses Y 1, Y 2 and Y 3. Multi-response optimization with desirability function approach has been used to simultaneously maximize Y 1 and Y 2, and minimize Y 3. Optimized values of various responses were: Y 1 =94%, Y 2 =99.7% and Y 3 =0.011kWh/kg of COD removed. Scum and sludge generated during EC of DBE have also been analyzed for the possibility of their disposal. [Copyright &y& Elsevier]

Abstract: The secondary effluent from paper and food industry wastewater still contains a high chemical oxygen demand and color intensity caused by the presence of difficult degradable organic compounds. These compounds are mostly humic-like substances. This study focused on two promising electrochemical methods for removal and recovery of humic like substances from industrial secondary effluent: membrane electrolysis and electro-coagulation. Membrane electrolysis removed 70% of the color at energy consumption 3kWh/m3. The chemical oxygen demand reduction in the electrolysis process was less efficient. Organic compounds were partly removed at the cathode by precipitation and partly transported to the anode side, which was dependent on the membrane material. The electro-coagulation treatment process efficiently removes chemical oxygen demand and color. The method has a lower operational cost compared to the membrane electrolyses and would be the best option for high polluted wastewater. These results show that the electrochemical methods are an interesting option for humic like substances removal/recovery and could compete with conventional oxidation and coagulation methods. [Copyright &y& Elsevier]

Experiments were carried out in a batch reactor to treat the oily effluent by electro-coagulation. The influence of operating parameters such as applied current, type of electrode and electrolysis time on electro-coagulation efficiency has been critically examined. The maximum percentage removal of chemical oxygen demand (COD) was 94% under optimum experimental conditions of pH 6.7, current density 6 mA/cm2, electrolysis time 40 mm, and using mild steel as anode. The remaining sludge in the reactor was analyzed by energy disperse analysis of X-rays (EDAX) and scanning electron microscope (SEM) analysis. The analysis confirms that the oily pollutant was removed by electroflotation and adsorption of the oily particles of precipitate during the electro-coagulation process. Electro-coagulation can be used as an efficient treatment technique for oily wastewater. [ABSTRACT FROM AUTHOR]

The purpose of this work was to provide an alternative to effluent treatment of an OCC paper recycling mill by electro-coagulation technique. The experiments carried out to find the optimum conditions for turbidity and biological oxygen demand (BOD) reduction of the effluent at four levels of electrolysis time (10, 20, 30 and 60 min), three initial suspension pH levels (3, 7.5 and 10), by two constant voltage of 9.0 and 12.0. The results indicated that electro-coagulation is an effective technique for treatment of paper recycling mill effluent. At optimum conditions, more than 99.7% of turbidity and 96.1% of BOD were effectively removed. [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]

Electro-coagulation (EC) of a distillery spent wash has been optimized by Box–Behnken design of surface response analysis in terms of color removal. The design was employed to derive a statistical model for the effect of parameters studied on removal of color using iron anodes. The current density (31 mA/cm2), dilution (17.5%) and time of electrolysis (4 hours) had been found to be the optimum conditions for maximum 95% color removal. The actual color removal at optimized conditions was found to be 93.5% which confirms close to the predicted response using response surface methodology. [ABSTRACT FROM AUTHOR]

An existing SBR plant in a rural area was retrofitted from a conventional fill-and-draw system to an intermittent-aeration system for additional nitrogen removal. This study indicated that organic and nitrogen removal efficiency was improved over that before the retrofitting. But effluent phosphorus concentration was increased gradually with the operating time. In the latter period of investigation, phosphorus concentration in effluent was higher than influent. It was regarded that an excessively accumulated phosphorus was released again under the anaerobic conditions of the sludge storage tank. The application of the electro-coagulation process was investigated as an alternative method in order to prevent phosphorus from re-releasing. A laboratory test for electro-coagulation indicated that T-P removal was more stable than the biological method only. In addition, it was confirmed that T-N and organic materials as well as T-P were removed simultaneously by the electrochemical reaction in the bioreactor combined with electrolysis by more than the bioreactor only. [ABSTRACT FROM AUTHOR]