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Avaliação preliminar da aplicação da Eletrocoagulação no tratamento de águas residuais da Indústria de Curtumes
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Este trabalho teve como objetivo realizar uma avaliação preliminar da aplicação da eletrocoagulação
(EC) no tratamento de águas residuais (AR) provenientes da indústria de curtumes, setor
caracterizado por efluentes com elevada carga poluente, nomeadamente matéria orgânica, sólidos
suspensos e metais pesados.
O estudo incluiu a caracterização do processo produtivo da indústria de curtumes e das águas
residuais geradas, bem como a análise dos sistemas de tratamento convencionais atualmente
utilizados. Para a avaliação do tratamento das AR provenientes da indústria de curtumes por EC, foi
desenvolvido um sistema laboratorial em modo descontínuo, no qual se testaram diferentes condições
operatórias, nomeadamente o tipo de elétrodo (ferro, alumínio e combinação Fe/Al) e a densidade de
corrente, associada a regimes de baixo e elevado consumo energético. Para efeitos de monitorização,
consideraram-se os parâmetros críticos deste tipo de efluente, nomeadamente, CQO, SST, cloretos,
sulfuretos, crómio total e gorduras.
Os resultados evidenciam que a EC permite a remoção de parâmetros relevantes, como sólidos
suspensos totais, crómio total e óleos e gorduras, sendo as eficiências de remoção mais elevadas
associadas a condições de maior densidade de corrente (maior consumo energético). Verificou-se
ainda que o tipo de material dos elétrodos influencia o desempenho do processo, com os sistemas à
base de ferro a apresentarem, de forma geral, melhores resultados, embora com maior produção de
lamas e maior desgaste dos elétrodos.
No entanto, as condições experimentais testadas não garantiram o cumprimento integral dos valores
limite de emissão para todos os parâmetros analisados, evidenciando a necessidade de otimização do
processo e eventual integração da EC com outras tecnologias de tratamento. Identificaram-se ainda
limitações associadas à ausência de repetibilidade experimental, à escala laboratorial e à
variabilidade das condições operatórias, que requerem investigação adicional.
Não obstante, considera-se que o presente estudo constitui uma base preliminar relevante para a
avaliação da EC no tratamento de águas residuais da indústria de curtumes, evidenciando o interesse
desta tecnologia como etapa complementar de tratamento e a necessidade de otimização e validação
futuras.
This work aimed to perform a preliminary assessment of the application of electrocoagulation (EC) for the treatment of wastewater generated by the tannery industry, a sector characterized by effluents with high pollutant loads, particularly organic matter, suspended solids and heavy metals. The study included the characterization of the tannery manufacturing process and the resulting wastewater, as well as a review of the conventional treatment systems currently applied. In order to evaluate the treatment of tannery wastewater by EC, a laboratory-scale batch system was developed, in which different operating conditions were tested, namely electrode material (iron, aluminium and Fe/Al combination) and current density, corresponding to low and high energy consumption regimes. For monitoring purposes, the critical parameters typically associated with this type of effluent were considered, namely chemical oxygen demand (COD), total suspended solids (TSS), chlorides, sulphides, total chromium, and oils and fats. The results demonstrate that EC is capable of removing relevant pollutants, particularly total suspended solids, total chromium and oils and fats, with the highest removal efficiencies being obtained under higher current density conditions, corresponding to higher energy consumption. The electrode material was also found to influence process performance, with iron-based systems generally providing the best results, although accompanied by higher sludge production and more pronounced electrode wear. However, the experimental conditions tested did not ensure full compliance with the discharge limit values for all the parameters analysed, highlighting the need for process optimisation and the possible integration of EC with complementary treatment technologies. Additional limitations were identified, namely the lack of experimental reproducibility, the laboratory-scale configuration and the variability of the operating conditions, all of which require further investigation. Nevertheless, the present study constitutes a relevant preliminary basis for the assessment of EC in the treatment of tannery wastewater, highlighting the potential of this technology as a complementary treatment stage and the need for further optimisation and validation.
This work aimed to perform a preliminary assessment of the application of electrocoagulation (EC) for the treatment of wastewater generated by the tannery industry, a sector characterized by effluents with high pollutant loads, particularly organic matter, suspended solids and heavy metals. The study included the characterization of the tannery manufacturing process and the resulting wastewater, as well as a review of the conventional treatment systems currently applied. In order to evaluate the treatment of tannery wastewater by EC, a laboratory-scale batch system was developed, in which different operating conditions were tested, namely electrode material (iron, aluminium and Fe/Al combination) and current density, corresponding to low and high energy consumption regimes. For monitoring purposes, the critical parameters typically associated with this type of effluent were considered, namely chemical oxygen demand (COD), total suspended solids (TSS), chlorides, sulphides, total chromium, and oils and fats. The results demonstrate that EC is capable of removing relevant pollutants, particularly total suspended solids, total chromium and oils and fats, with the highest removal efficiencies being obtained under higher current density conditions, corresponding to higher energy consumption. The electrode material was also found to influence process performance, with iron-based systems generally providing the best results, although accompanied by higher sludge production and more pronounced electrode wear. However, the experimental conditions tested did not ensure full compliance with the discharge limit values for all the parameters analysed, highlighting the need for process optimisation and the possible integration of EC with complementary treatment technologies. Additional limitations were identified, namely the lack of experimental reproducibility, the laboratory-scale configuration and the variability of the operating conditions, all of which require further investigation. Nevertheless, the present study constitutes a relevant preliminary basis for the assessment of EC in the treatment of tannery wastewater, highlighting the potential of this technology as a complementary treatment stage and the need for further optimisation and validation.
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Palavras-chave
Eletrocoagulação Indústria dos curtumes Águas residuais Remoção de poluentes