Removing Fe, Zn and Mn from steel making plant wastewater using RO and NF membranes

Abstract

Background and purpose: Excessive amount of heavy metals in industrial wastewater is a seriously crucial issue and requires efficient methods to be introduced and dealt with. Meanwhile, steel making plants as productive units in every country release large amounts of fluid into surface and underground sources. Typically, this wastewater contains heavy metals in minor amounts, while this amount could cause severe damages to the living organisms. Materials and methods: In this study, removing iron, manganese, zinc and total dissolved solid in a typical wastewater resulted from steel making plant was considered using reverse osmosis (RO) and nanofiltration (NF) membranes. At first, different pH values and operating pressures were applied to the wastewater. Then, these parameters were evaluated for a wastewater only containing iron to compare the interaction of other elements in iron removal. Results:The results indicated that RO and NF membranes could successfully treat industrial wastewater containing several heavy metals with high concentrations of Fe, Zn and Mn, especially at optimum pH and pressure. Moreover, the interaction of other heavy metals and components in the influent decreased the efficiency of RO but improved the NF efficiency to remove iron. To have a better image, a formula was proposed for each method to represent the influence of the parameters on removal rates. Finally, cost estimation for both procedures showed that RO was not economicallytechnically efficient in comparison with NF. Conclusion: NF showed an acceptable performance with high water flow which made it more suitable for industries. At the end, the relative cost analysis showed that even if the initial price of NF is high, the energy consumption and total cost of RO will be higher.

The Effect of Organic Matter on Heavy Metals Removal from Simulated Wastewater using a Reverse Osmosis Membrane Process

“…Higher rejection rates were found at pH levels equal to 4 or above 6, with low Cd concenterations in the feedwater. Mirbagheri et al (2016) [13] also employed RO membranes to separate Fe, Zn, and Mn from steel industry wastewater at different pHs and feed pressures. They indicated that a high quantity of Fe, Zn, and Mn in industrial wastewater was effectively removed using RO membranes when the pH and pressure were optimized.…”

“…Researchers have been focusing on the RO method as one of the most promising ways to treat water in recent years. Recent studies have focused on the removal of heavy metals from contaminated water using RO membrane technology [9–13] . For instance, Kheriji et al.…”

“…Recent studies have focused on the removal of heavy metals from contaminated water using RO membrane technology. [9][10][11][12][13] For instance, Kheriji et al (2015) [12] employed RO membrane to remove Cd + 2 ions from industrial wastewater. Cd + 2 retention was examined using model solutions under various pressures, concentrations, ionic strengths, and pH values.…”