Optimization of an integrated electrodisinfection/electrocoagulation process with Al bipolar electrodes for urban wastewater reclamation

Abstract

In this work, a novel integrated electrochemical process for urban wastewater regeneration is described. The electrochemical cell consists in a Boron Doped Diamond (BDD) or a Dimensionally Stable Anode (DSA) as anode, a Stainless Steel (SS) as cathode and a perforated aluminum plate, which behaves as bipolar electrode, between anode and cathode. Thus, in this cell, it is possible to carry out, at the same time, two different electrochemical processes: electrodisinfection (ED) and electrocoagulation (EC). The treatment of urban wastewater with different anodes and different operating conditions is studied. First of all, in order to check the process performance, experiments with synthetic wastewaters were carried out, showing that it is possible to achieve a 100% of turbidity removal by the electrodissolution of the bipolar electrode. Next, the effect of the current density and the anode material are studied during the ED-EC process of actual effluents. Results show that it is possible to remove Escherichia coli and turbidity simultaneously of an actual effluent from a WasteWater Treatment Facility (WWTF). The use of BDD anodes allows to remove the E. coli completely at an applied electric charge of 0.0077 A h dm(-3) when working with a current density of 6.65 A m(-2). On the other hand, with DSA anodes, the current density necessary to achieve the total removal of E. coli is higher (11.12 A m(-2)) than that required with BDD anodes. Finally, the influence of cell flow path and flow rate have been studied. Results show that the performance of the process strongly depends on the characteristics of the initial effluent (E. coli concentration and Cl(-)/NH(4)(+) initial ratio) and that a cell configuration cathode (inlet)-anode (outlet) and a higher flow rate enhance the removal of the turbidity from the treated effluent.

Energetic, economic and environmental assessment of the pyrolysis and combustion of microalgae and their oils

“…The mineral composition of the biomass was measured by using an inductively coupled plasma spectrometer (model Liberty Sequential, Varian) according to the procedure described by Cotillas et al [14] (plasma emission spectroscopy). In order to evaluate the total metal concentration, microalgae biomass samples were diluted to 50:50 v/v using 4N HNO 3 in order to ensure the total solubility of the metal.…”

Electrochemical Treatment of Dye Bearing Effluent with Different Anode–Cathode Combinations: Mechanistic Study and Sludge Analysis

“…This may be due to the fact that, at appropriate j values, sufficient coagulants are generated via anodic dissolution and they interact with OH ions to form respective precipitates (eqs 1−4) to remove impurities by adsorption and flotation (precipitation) mechanisms. 30 Figure S2a,b (Supporting Information). After 150 min of electrolysis, 68.4% TOC removal and 98.5% turbidity removal were observed at optimum j with the SS−SS electrode combination.…”

Recent developments of electro-oxidation in water treatment — A review

“…Coupling EO technology with some other advanced water treatment technique improved the disinfection results [147][148][149][150][151][152]. Sonoelectrocatalytic disinfection using TiO 2 as electrode effectively inactivated E. coli bacteria [147].…”

“…Cotillas et al [150] optimized an integrated electrodisinfection/electrocoagulation process for urban wastewater reclamation. Results showed that the performance of the process strongly depended on the characteristics of the initial effluent and cell configuration cathode (inlet)-anode (outlet).…”