Condutivity effect in electro-coagulation-flotation applied to physico-chemical wastewater treatment

Mário Luiz Rodrigues Foco, Francisco Javier Cuba Terán

Abstract


This study reports on the effect of conductivity on the simultaneous applicability of water electrolysis , chemical coagulation and flotation fundamentals in the treatment of wastewater with large amounts of suspended matter, characterizing electro-coagulation-flotation (ECF) . Results from experiments carried out in a pilot study implanted and operated in the Laboratory of Environment Control (LCA), at the State University of Campinas in Limeira are presented. ECF was developed in an electrolytic reactor where water passed through aluminum electrodes connected to a power supply. Electrochemical reactions promoted Al3+ ions emission from anode, neutralizing repulsive pollutant forces, forming flakes. An evolution of micro hydrogen bubbles occurred, carrying the flakes to the top of the solution, causing flotation and polluter removal. System monitoring aimed at reaching optimal operation conditions regarding time of liquid permanence in the reactor, influence of the NaC1 addition on the increase of affluent conductivity, and influence of polarity inversion over cathodic passivation. Results from carwash wastewater treatment reported 86% efficiency rate for color, 90,15% for turbidity and 85,43% for oil and axle-grease removal.

Keywords


Electro-coagulation-floatation; Wastewater treatment; Chemical coagulation.



DOI: http://dx.doi.org/10.5433/1679-0375.2007v28n2p99

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