A comparison of aluminium and iron based coagulants on hardness and TDS
Student name: Ms Himanshi Gupta
Guide: Dr Chander Kumar Singh
Year of completion: 2016
Host Organisation: Water Health India Pvt Ltd
Supervisor (Host Organisation): Ms Shubha Menon
Abstract: Attempts were made in this study to examine the effectiveness of coagulant
addition to reverse osmosis reject water to remove some of its hardness and total
dissolved solid content (Amuda et al., 2006). Experiments were conducted using
the standard Jar test procedure to determine the performance of both aluminium
based and iron based coagulants namely aluminium sulphate, ferrous sulphate
and ferric chloride(Amuda et al., 2006). Coagulation flocculation, sedimentation
and filtration processes were employed in the experiments for the reduction in
total hardness and total dissolved solid content. The dosages and pH level for
three of coagulants were varied to understand the relationship between pH level
and coagulant dosage. The maximum total hardness removal efficiency for
aluminium sulphate was obtained at 97% with addition of 1 normal 2ml solution,
whereas TDS concentration only saw an increase throughout the experiment. For
ferrous sulphate maximum total hardness removal was again 97% on addition of
1ml of 1 normal ferrous sulphate solution. And for ferric chloride maximum
removal efficiency of total hardness was 87% on usage of 12.5ml of 1 normal
ferric chloride stock. Ferric chloride produced more voluminous and more
compacted sludge than aluminium sulphate (Amuda et al., 2006).
Key words: coagulant, coagulation, flocculation, hardness, Total dissolved solid
