Remediation of Wastewater Containing Insecticides by Electrocoagulation in a New Electrochemical Reactor

The rate of methomyl insecticide removal from synthetic wastewater by electrocoagulation was studied using a cell that contains a vertical serpentine tube Al anode placed between two vertical stainless steel screen cathodes. Besides the high area per unit volume of the anode, the inner surface of the serpentine tube anode has the potential of acting as a built-in cooler to remove excess heat which may adversely affect the rate of electrocoagulation, especially in high current large-scale cells which treat low conductivity waste solutions. Variables studied were initial methomyl concentration, current density, pH, NaCl concentration, temperature, and degree of stirring. Under optimum conditions, 100% of the methomyl was removed in 40 min. The % COD removal was found to increase with increasing all the variables investigated, except for stirring where the % COD removal increases up to a certain limit beyond which increasing the degree of stirring did not affect the % COD removal. Electrical energy consumption ranged from 0.11 to 0.65 kW.h/kg of the removed methomyl depending on the operating conditions. The importance of the results in treating wastewater discharged by insecticide plants and agricultural runoff water was highlighted.

Automated summary

In this study, the removal rate of methomyl insecticide from synthetic wastewater was investigated using electrocoagulation. The results showed that under specific conditions, complete removal of methomyl could be achieved within 40 minutes, and the removal rate increased with the increase of various variables. The findings are of great importance for the treatment of wastewater from insecticide plants and agricultural runoff water.