Abstract—In this study, treatment efficiency of magnesium chloride (MgCl2.6H2O) was compared with respect to ferrous sulphate (FeSO4.7H2O), polyaluminium chloride (PACl), and aluminium chlorohydrate (ACH) for the treatment of textile wastewater. Treatment efficiency was assessed in terms of decolourisation and chemical oxygen demand (COD) reduction of synthetic textile wastewater containing reactive, direct and disperse dyes, along with the other chemical constituents that are normally released from different textile processing units. MgCl2.6H2O/Lime produced colour removal efficiency of 99.68% at a dosage 1200mg/L for the wastewater containing all the three dyes together. MgCl2.6H2O/Lime was also found to be the most effective coagulant system for treatment of textile wastewater containing only reactive dye, which produced 99.73% colour removal at a dosage of 1100 mg/L. For both the direct and disperse dyes, ACH was found to be superior over MgCl2.6H2O/Lime, FeSO4.7H2O/Lime, and PACl. Industrial grade ACH, which is normally used as polyelectrolyte, for the first time was used as coagulant in this study and was also appeared to be significant for decolourisation of textile wastewater containing all the three dyes together. From this study, MgCl2.6H2O/Lime was recommended as the best coagulant for the decolourisation of textile wastewater having very high original pH.

Index Terms—Aluminium chlorohydrate (ACH), coagulation, colour removal, magnesium chloride (MgCl2.6H2O), polyaluminium chloride (PACl), textile wastewater.

Authors are with the School of Infrasturcture, Indian Institute of Technology Bhubaneswar, Odisha, India (email: akshaya@iitbbs.ac.in; pbhunia@iitbbs.ac.in; rrdash@iitbbs.ac.in).

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Cite: Akshaya Kumar Verma, Puspendu Bhunia, and Rajesh Roshan Dash, "Supremacy of Magnesium Chloride for Decolourisation of Textile Wastewater: A Comparative Study on the Use of Different Coagulants," International Journal of Environmental Science and Development vol. 3, no. 2, pp. 118-123, 2012.