Implementation of the electrochemistry in wastewater treatment

Abstract

The treatment for wastewater from the two different process, tannery and flower planting wastewater by electrocoagulation was evaluated. The experiments carried out in a reactor at laboratory settings monopolar with iron and aluminum electrodes operating in discontinuous mode (batch).

In this study, the treatment of effluent of tannery wastewater by electrocoagulation technology was evaluated. As part of the study, a small-scale reactor with a monopolar configuration was built with iron and aluminum electrodes, operated in batch mode. Preliminary tests were carried out with a sample volume of 150 ml, with a Immersed area of 27 cm2 and a time of residence of 30 minutes, and the optimal values of the agitation 382 rpm and lectrodes distance 5 mm. In the final design experiments, of the initial concentration of the sample, the voltage and the types of electrodes were chosen as factors. The optimal results obtained after statistical analysis were a voltage of 13 voltios, an agitation of 382 rpm, aluminum electrodes, an initial solution concentration of 2364,57 ppm and an distance between electrode of 5 mm. The model was further evaluated with the optimal conditions for both solution, the diluted solution (2364,57 ppm) and a raw solution (5456,7 ppm). Kinetics of the process was evaluated by chromium, removal of COD and TOC, as well as DBO5 before and after the treatment. A volume of 500 ml was treated during a period 60 minute of reaction. The natural sample presented a chromium removal of 71.98%, COD removal of 50.67%, TOC removal of  19% and a biodegradability increase of 72.88% in the wastewater. The diluted solution presented a chromium removal of 99.76%, COD removal of 60%, TOC removal of 51.23%, and biodegradability of wastewater increase of 77.22%.