Electrochemical treatment of industrial cooling tower blowdown water using magnesium-rod electrode

Abstract

Cooling tower blowdown water (CTBW) was treated with simple electrocoagulation (EC) using magnesium-rod electrode. This study examined the effects of the treatment parameters (current density, electrolysis time, electrode distance, initial pH and stirring speed) on the EC ability to remove hardness ions (Ca2+, Mg2+) and dissolved silica from CTBW. Under the optimized condition, magnesium-rod electrode removed 51.80% and 93.70% respectively for total hardness and silica; with an operating cost of 0.88 US$/m3 treated CTBW. EC sludge has been characterized by SVI, SEM-EDX, XRD, and FTIR exploring the ability of sludge to settle, surface morphology, elemental composition, crystalline type, and functional groups. It can be concluded that EC using magnesium-rod electrode can be successfully applied for the treatment of CTBW to facilitate its reuse.

Keywords

• Cooling tower blowdown water
• Electrocoagulation
• Magnesium-rod electrode
• Scale ions removal
• Operating cost
• Sludge characterization