Electrocoagulation of fermentation wastewater by low carbon steel (Fe) and 5005 aluminium (Al) electrodes

Abstract

Successful application of electrocoagulation technology requires a thorough evaluation of electrode behaviour. This study is concerned with the treatment of fermentation wastewater, generated by molasses-fed biorefineries in large volumes and containing high concentrations of biorecalcitrant, coloured organic melanoidins that form a highly dispersed colloid. The polarisation behaviour, surface morphology and current efficiency of both hot rolled coil steel and 5005 aluminium electrodes were investigated. The steel electrodes were found to be susceptible to aggressive anodic pitting which is attributed to the high chloride content of the wastewater, while the aluminium exhibited anomalous corrosion of the anode and cathode. The redox potential of the wastewater has a significant effect on Fe 2? /Fe 3? speciation with steel electrodes and thus on the decolourising efficiency of electrocoagulation. The practical implications of the corrosion characteristics are discussed.

Development of a novel electrochemical coagulant dosing unit for water treatment

“…In the case of the ECU device, there exists a decrease in the Redox potential for increasing the applied charge. This decrease in the Redox potential means a higher reductive capacity of the effluent, what can be directly related to a higher Fe 2+ :Fe 3+ ratio . In the case of chemical dosing, the redox potential remains positive, indicating a high proportion of Fe 3+ in the iron speciation.…”

Impedance spectra of anodic dissolution of iron in distillery vinasse

“…During the last decade, the EC technique has been recognized as an effective process for various water treatment applications [3], particularly, EC has been applied by some researchers in biologically pretreated vinasses. Gadd et al (2010) used electrodes of iron and they reached decrease 99% in color and 80% on COD [4]. Ryan et al (2008) obtained 90% of color removal and up to 50% of COD [5]; likewise, Thakur et al (2009) diminished the COD in 62% and 98% color by using stainless steel electrodes [6].…”

The importance of current distribution and cell hydrodynamic analysis for the design of electrocoagulation reactors

“…Electrocoagulation (EC) has been evaluated and applied to the removal of a wide variety of pollutants; however, this technique is not yet considered an established technology because of the lack of adequate scaling procedures for the design of electrochemical reactors for EC purposes . Despite this known disadvantage, most of the reported work on EC uses empirically designed cells, which are generally based on the parameters that determine the kinetics of pollutant removal (e.g.…”