Laboratory and pilot testing of electrocoagulation for removing scale-forming species from industrial process waters

Abstract

This study investigated the performance of electrocoagulation using iron and aluminum electrodes for removing silica, calcium and magnesium from cooling tower blowdown and reverse osmosis reject waters. Experiments were conducted at both the bench and pilot scales to determine the levels of target species removal as a function of the coagulant dose. At the bench scale, aluminum removed the target compounds from both cooling tower blowdown and reverse osmosis reject more efficiently than iron. A 2 mM aluminum dose removed 80 % of the silica and 20 to 40 % of the calcium and magnesium. The same iron dose removed only 60 % of the silica and 10 to 20 % of the calcium and magnesium. When operated with iron electrodes, pilot unit performance was comparable to that of the bench unit, which suggests that such systems can be scaled-up on the basis of coagulant dose. However, when operated with aluminum electrodes the pilot unit underperformed the bench unit due to fouling of the electrode surfaces after a few hours of operation. This result was completely unexpected based on the short-term experiments performed using the bench unit.

Application of Electrocoagulation Process Using Iron and Aluminum Electrodes for Fluoride Removal from Aqueous Environment

“…(15) During the past years, Electro-coagulation method has been proposed as an effective method to treat various wastewaters such as landfill leachate, restaurant wastewater, saline wastewater, tar sand and oil shale wastewater, urban wastewater, laundry wastewater, nitrate and arsenic bearing wastewater and chemical mechanical polishing wastewater. (16)(17)(18) Electro-coagulation is a simple and efficient method to remove the flocculating agent generated by electro-oxidation of a sacrificial anode and generally made of iron or aluminum. In this process, the treatment is performed without adding any chemical coagulant or flocculants.…”

Effective parameters for the adsorption of chromium(III) onto iron oxide magnetic nanoparticle

“…One of these techniques is the process of electrocoagulation which is a novel and efficient method for heavy metals removal (Akbal and Camc 2011;Arroyo et al 2009;Bhatti et al 2009;Schulz et al 2009;Sun et al 2009). Other methods for removing metal ions from wastewater are deposition, evaporation, solvent extraction, ion exchange, reverse osmosis, separation by membrane, etc.…”

Evaluation of electrocoagulation for the pre-treatment of coal seam water

“…Increasing the contact time from 30 to 60 s also enhanced the degree of alkaline earth removal. Schulz et al [50] in their laboratory and pilot study of electrocoagulation for removing scale-forming species from cooling tower blowdown and reverse osmosis reject waters only achieved a 20-40% removal of calcium and magnesium. In contrast, Malakootian and Yousefi [51] reported an efficiency of 95.6% in hardness removal using electrocoagulation.…”