Study of electroflotation method for treatment of wastewater from washing soil contaminated by heavy metals

Electroflotation method (EFM) for treatment of synthetic solutions simulating wastewater from washing soil contaminated by drilling fluids from oil wells was investigated in this paper. Experiments were carried out to examine the effects of the operating conditions on the removal of lead, barium and zinc from solutions containing 15 mg dm(-3) for each metal representing a typical concentration of wastewater generated in the washing soil in this treatment. The experimental results showed that it is possible to remove these heavy metals by electrocoagulation/electroflotation (ECF) attaining 97% of removal using stainless steel mesh electrodes with a power consumption of 14 kWh m(-3). The optimal conditions of treatment were sodium dodecyl sulfate (SDS) in a molar ratio 3:1, current density around 350 A m(-2), ionic strength 3.2 x 10(-3) M, pH = 10.0 and 20 min of ECF. This study newly indicated that the proposed method is adequate to simultaneously treat the common heavy metals found in the drilling fluids oil wells. (C) 2014 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda. All rights reserved.