Effect of chemical pretreatment on the silt density index of brackish water from north and south Kuwait

AbstractIn this study, the effect of chemical pretreatment with powdered activated carbon (PAC), ferric chloride, and aluminum chloride at the different concentrations of 10, 30, and 60 ppm on the silt density index (SDI) value of brackish water was examined. Generally, PAC pretreatment was found to be the best pretreatment method. Pretreatment with 10 ppm of PAC resulted in the lowest SDI value of 3.5, which is approximately 44.4% lower than untreated brackish water. After pretreatment with PAC, scanning electron microscopy (SEM) of the filter surface showed large graphite-like particles. An intermediate blocking mechanism produced the best fit for the filtration data from PAC pretreatment. The SEM images of the filter surface show a thick cake layer formation in the aluminum chloride and ferric chloride pretreatments. The cake filtration blocking mechanism was the best fit for brackish water treated with aluminum chloride and ferric chloride.