Tratamento de lixiviado de aterro da indústria de couro por processos combinados

Abstract

This study presents a multistage treatment strategy for the treatment of industrial landfill leachate from the leather industry. Firstly, a treatment line was designed taking into account the physical-chemical characteristics of the leachate. This strategy included: (i) an initial biological process for removal of biodegradable organics, ammonium and alkalinity, (ii) a coagulation/flocculation process for partial removal of organics, color and suspended solids, and total elimination of chromium, (iii) an advanced oxidation process (POA) or electrochemical POA (POEA) for degradation of recalcitrant organics and biodegradability enhancement, and (iv) a final biological polishing step. Two biological treatment configurations were considered as first stage: one comprising nitrification and the other comprising nitrification-denitrification. The influence of each type of biological treatment in the subsequent phases was evaluated. The highest efficiency of the process was nitrification-denitrification, coagulation/flocculation, FEFUVA followed by a final biological treatment achieving a total process removal of 99.8%, 98% and 99.2% of COD, nitrogen and chromium respectively, permitting compliance with the Portuguese discharge limits for effluents to be discharged to wastewater treatment plants (WWTP) and Brazilian wastewater treatment plants to be discharged to water bodies after completion.