An electrocoagulation unit for the purification of soluble oil wastes of high COD

Abstract

In spite of abundant literature on the topic, the efficiency of electrocoagulation for a specific effluent cannot be predicted in advance. Prior to designing an industrial wastewater treatment unit, preliminary treatment tests have to be done using different soluble oil wastes with a very high chemical oxygen demand (COD). The influence of various parameters can then be assessed. Coagulant dose, linked to the electrical charge passed and the nature of the waste, seem to be the controlling parameters of process efficiency. The results obtained at the laboratory‐scale have been confirmed in a small pilot cell, and an industrial unit has been designed. A preliminary economic study shows that electrocoagulation may be competitive with current treatment technologies. From knowledge gained at bench‐scale, we concluded that electrocoagulation appears to be a suitable process for treatment of soluble oily wastes with high COD.

Electrotreatment of industrial copper plating rinse effluent using mild steel and aluminum electrodes

“…However, the effect was less significant in the case of the Al electrode. It has been reported by several authors 25,31,32 that chloride ions are able to strongly promote anodic dissolution by avoiding inhibition phenomena at the surface of sacrificial anodes. In fact, during electrocoagulation the surface of the electrode is covered by an oxide layer that is continuously formed by water splitting at the solution/oxide interface.…”

“…13 -24 In spite of ample literature on the topic, the efficiency of the electrocoagulation process for a specific effluent cannot be predicted in advance. 25 The performance of an electrotreatment process using mild steel (MS) and/or aluminum (Al) as the electrode material strongly depends on the pH of the solution and it varies continuously during the process. Stopping the experiments at the same transient pH at different time intervals with the same initial conditions and different current density, equilibration does not lead to the same final/equilibrium pH unless the pH is close to the buffer pH.…”

Treatment of wastewater from biodiesel plants using microbiological reactor technology

“…Chemical coagulation and electrocoagulation processes are also proposed for the treatment of wastewater from biodiesel plants (Chavalparit et al 2009). However, the major drawbacks of the coagulation process, the requirement of a large treatment area and the contamination of chemical coagulants in the treated wastewater, remained (Ngamlerdpokin et al 2011;Feng et al 2004), and electrocoagulation process is possibly suitable for a primary treatment of biodiesel wastewater but it still requires a further biological treatment process (Emamjomeh et al 2009;Calvo et al 2003;Bolzonella et al 2006;Chavalparit et al 2006).…”

Electrolytic Treatment of Wastewater in the Oil Industry

“…Different processes have been described for the treatment of such effluent, but the most frequently used are chemical destabilization [8,9] and electrochemical destabilization [10,11]. Biological processes are rarely used since these effluents usually contain biocides [12].…”