This study investigated the effectiveness of a coagulant, Recycled Ferric Chloride (RFC)
for reused in thickening the municipal sludge and treating landfill leachate. The RFC is
generated from sludge produced from a groundwater treatment plant through a digestion
process. The study had been divided into two (2) phase. For both phases of the study, jar
tests were conducted for the treatment process. In the jar test, coagulants such as alum,
ferric chloride, ferrous sulphate and RFC were evaluated. In the first phase of the
experimental study, jar tests were conducted on sludge obtained from a wastewater
treatment plant. Settleability tests were conducted in the thickening process. The
supernatant were then measured for chemical oxygen demand (COD), colour, and total
suspended solids (TSS). Tests were conducted in triplicates. The raw sludge settling rate
was found to be 2.4 cm/min. The optimum settling rates for alum, ferric chloride, ferrous
sulphate and RFC was found to be 3.13 cm/min, 1.86 cm/min, 2.5 cm/min and 4.5
cm/min. RFC improved the settling rate by 88% and also removed colour, COD and TSS
at 42%, 54% and 88%, respectively at the optimum settleability dosage. For the second
phase of the experimental study, the jar tests were conducted on leachate obtained from
Pulau Burung Landfill Site. The supernatant were then measured for chemical oxygen
demand (COD), colour, and total suspended solids (TSS). RFC improved the colour and
COD removed at 64% and 60% respectively at the optimum dosages. However further
research need to be done on the suspended solid removal since the result shows that the
suspended solid is increasing after the treatment process. RFC managed to remove the
suspended solid for 32% at the optimum dosag
