Electrocoagulation using perforated electrodes: An increase in metalworking fluid removal from wastewater.

• An electrocoagulation system was built to separate emulsified metal cutting fluid from water. • Both pH and metal cutting fluid removal increased with time following an exponential behavior. • The effect of drilling holes in the electrodes was studied. • Removal of 90% of the metal cutting fluid was achieved. • Removal efficiency can be increased if the electrodes are perforated. A continuous electrocoagulation reactor with electrode polarity switch was used for removal of a metalworking fluid from synthetic oily water. The effects of perforating the aluminum electrodes, changing the number of holes, flow rate and the distance between electrodes were studied. Higher values of flow rate reduced final pH. Perforating the electrodes led to faster convergence of pH to its maximum value with no measurable increase in mass loss. If the distance between electrodes is also increased, there is an improvement in efficiency. With 10 holes, adjusting flow rate and inter-electrode distance, 90.2 ± 0.3% oil removal was achieved with a final pH of 8.83, which is within limits allowed by legislation. [ABSTRACT FROM AUTHOR]