Assessing potential of nanofiltration for sulfuric acid plant effluent reclamation: Operational and economic aspects

• Published in: Separation and purification technology 2019-09, Vol.222, p.369-380
• Main Authors: Reis, Beatriz Gasparini, Araújo, Ana Lívia B., Vieira, Camila C., Amaral, Miriam Cristina Santos, Ferraz, Helen Conceição
• Format: Article
• Language: English
• Subjects: Arsenic; Gold mining; Nanofiltration; Sulfate; Sulfuric acid plant wastewater; Wastewater reclamation; Water reuse
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2019.04.048

•NF is a suitable technology to treat sulfuric acid plant wastewater.•A removal of 94% of sulfate, 98% of calcium, 85% of As III and 75% of As V was achieved.•The retention of higher valence counterions to balance the retained co-ion loads was the most important mechanism observed.•The membrane fouling occurs mainly due to cake formation.•The system cost was estimated in 551.250,00 US$ and the treatment 0.364–0.446 US$ m−3 wastewater. Sulfuric acid plant wastewater is characterized by low pH and high concentrations of sulfate and metals, including arsenic, which is a toxic element that requires specific treatment. This study aimed to investigate the sulfuric acid plant wastewater treatment using NF by evaluating the main NF operational conditions (feed pH, applied pressure and permeate recovery rate) and the preliminary capital and operational cost. The results showed the NF potential to treat the wastewater. The retention of higher valence counterions to balance the retained co-ion loads was the most important mechanism observed. By combining the best operational conditions (feed pH = 2, applied pressure = 10 bar and permeate recovery rate = 45%), retention of 94% of sulfate, 98% of calcium, 85% of As III and 75% of As V was achieved and permeate could be reused in industry. The NF system had its CapEx estimated at US$ 551.250,00 and the OpEx ranged from 0.364 to 0.446 US dollars per cubic meter of wastewater for estimated membrane lifespan of 5–1 year. Savings of more than US$ 99,000 year−1 could be achieved with the industrial reuse of the permeate, which could reduce the water consumption by approximately 551,880 m3 year−1.