Mixed Wastewater Treatment by Electro-Coagulation

Abstract

Electrocoagulation is an empirical water treatment technology that has had many different applications over the last century. It has proven its viability by removing a wide range of pollutants. The approach to reactor design for continuous process has been shown, however, with little or no reference to previous designs or basic principles. This thesis reviewed the COD & TSS removal and also the reactor designs for continuous process. This design, using packed material, decision will help to provide a new basis for future continuous electrocoagulation reactor designs. This innovative approach was applied to 0.5 L batch electrocoagulation reactor and 1 L continuous electrocoagulation reactor treating mixed polluted water. In experiments identified current (density), time, and mixing as the key operating parameters for electrocoagulation and define the continuous electrocoagulation. Electrocoagulation process defines both coagulant and bubble generation. The experiments were carried out based on the current as key parameter. As the current increases, the mechanism shifted towards the higher generation of hydroxyl ion, which increases the required potential. In particular, formation of the positively ion species increased solution pH. As time progresses, pollutant concentration decreases, shown in COD removal graphs as iron additions continue iron hydroxide/oxide precipitates. The bubbles are lightly removing the precipitate through the solution. Consequently, aggregates are formed, indicated by floatation. Floatation is an inherent aspect of the electrocoagulation reactor via the production of electrolytic gases. In the reactor, pollutants are removed through either by flotation or settling. As current increases, both settling and flotation rates increase due to the constant additional coagulant. This faster removal is balanced by a decrease in the coagulant. Consequently a tradeoff exists between removal time and coagulant efficiency that can be evaluated economical.