Investigating the Effect of Colloidal Foulants on SDI and MFI Tests

Creative Commons License

Gösterişlioğlu D. G. , Türk O. K. , Çakmakcı M.

2ndInternational Congress of Engineering and Natural Sciences Studies (ICENSS-2022), Ankara, Turkey, 7 - 09 May 2022, pp.133-140

  • Publication Type: Conference Paper / Full Text
  • City: Ankara
  • Country: Turkey
  • Page Numbers: pp.133-140


Silt density index (SDI) and Modified fouling index (MFI) are tests to measure and assess the fouling potential of pressure driven membranes such as reverse osmosis (RO) and nanofiltration (NF), which are widely used in water treatment applications. The process efficiency and the useful membrane life of such systems are mainly affected by the fouling phenomenon. Membrane fouling happens by the deposition of solid matters present in the feed water onto the membrane surface. Foulants such as particulate and colloidal matters cause plugging of the membrane and adversely impact the process productivity and operating costs. A comprehensive understanding to the fouling potential of the feed water and the reliability of the fouling index is crucially important in the design and operation phases of such systems. In this study, SDI and MFI experiments were carried out with synthetic feed water solutions containing different combinations of particle and colloidal foulant concentrations. The filtration performance data were presented systematically, and the reliability and sensitivity of both indices were compared. MFI values were sensitive to both particle and colloidal foulants and exhibited good consistency with increasing foulant concentration. Plant operators and academicians are encouraged to utilize the MFI test as a fouling prediction tool.