Estimating Energy Consumption and Cost for the Electrocoagulation of Arsenic-laden Water (ECAR) Using Iron Electrodes

Abstract

In some areas in Pampanga, arsenic concentration from handpumps reaches up to 300 μg/L, 10 times higher than the safe limit for drinking water. An efficient way of reducing elevated arsenic concentration is through electrocoagulation (EC) process with the use of iron electrodes. However due to several factors, the efficiency of the technique is decreased. This study focuses on determining the energy consumption and cost through time. The cost per cycle was estimated through the power consumption and projecting its growth with time. One 600 L cycle costs around $0.60 to $1.10 which is approximately $0.001 to $0.002 per liter of water. This value increases through each cycle until half of the electrode is consumed (500 cycles) and is to be replaced. The current processing time was set at 30 mins, charge dosage of 150 C/L, applied current of 16.67 mA, and an electrode area of 6.6 cm2. One factor examined which may have caused the increase is the formation of passivation layer on the electrode surface. It was described using linear sweep voltammetry (LSV) and Tafel extrapolation method. The resistance due to charge transfer was determined to be increasing per cycle.