Treating hydraulic fracturing produced water by electrocoagulation

Hydraulic fracturing oil- and gas-produced water is frequently highly impaired. While it is often deep well injected, there is a great deal of interest in treating and recovering this water for beneficial uses. However, multiple-unit operations are needed if these wastewaters are to be recovered. Electrocoagulation is considered a promising pretreatment technology. Herein, we have investigated the use of aluminum electrodes for electrocoagulation as a pretreatment operation. The effects of electrode arrangement, applied current, reaction time, pH and inter-electrode distance on the quality of the treated water have been investigated. The results obtained here indicate that electrocoagulation can obtain good removal of turbidity (95%), total suspended solids (TSS) (90%) and total organic carbon (TOC) (69%) by carefully choosing the reaction conditions. Sedimentation was used to separate the treated water from the sludge. The performance of the electrocoagulation process depends strongly on the quality of the feed water. The viability of a practical continuous electrocoagulation process will depend on the volume (footprint) of the reactor, which in turn will depend on operating conditions and the quality of the feed water.