Avaliação das técnicas eletrolíticas de eletrocoagulação-eletroflotação e eletro-oxidação separadas e conjugadas aplicadas no tratamento de lixiviados

Abstract

The current solid waste policy had generated many dumps or sanitary landfills, with leachate generation for decades that is difficult to treat due the continuous degradation of the organic matter, with considerable changes on quality in the life of the landfill. This work evaluated the electrolytic techniques applied in the treatment of the leachate of BR/RJ 01, BR/RJ 02 (nanofiltration concentrate) and BR/RJ 03 (reverse osmosis concentrate) landfills; aiming the removal of chemical oxygen demand (COD). In initial assays electrocoagulation-electroflotation (ECF) with aluminum electrodes (Al) was applied in leachate treatment of BR/RJ 01 and BR/RJ 02 landfills, obtaining 50 to 64% of COD removal with best current density (CD) of 30 A/m2 . In a second phase applying electro-oxidation (EO) assays with stainless steel (SS), titanium (Ti) and titanium doped with ruthenium oxide (Ti-RuO2) electrodes, yielding 43 to 54% of COD removal with best CD of 331 A/m2 . In a third phase, conjugated and simultaneous processes were applied in a single reactor with best CDs, with Al electrodes in ECF and EO with SS, Ti and Ti-RuO2 electrodes, showing that ECF with Al electrodes and EO with Ti-RuO2 electrodes yield the best COD removal of 79%. In the fourth phase, conjugated and simultaneous processes were applied with the best CDs in separate reactors with Al electrodes in ECF and Ti-RuO2 in EO, with COD removal of 87%. In all process’s solids, water and metals content in the scum were also evaluated, showing that both processes remove heavy metals and generated scum have low content of water.