Thickening of Municipal Sludge and Treatment of Leachate Using Recycled Ferrous Sulphate (RFS) Extracted from Groundwater Treatment Plant Sludge

The suitability and effectiveness of recycled ferrous sulphate (RFS) extracted from
groundwater treatment sludge to improve settleability of municipal sludge and treatment
leachate was investigated in this study. The groundwater sludge was taken from Chicha
Water Treatment Plant, Kelantan. Since the groundwater sludge contains non-hazardous
metal like iron and manganese, it cannot be discharge plainly without proper treatment
because if happen, it may lead to the pollution of surface water and ground water system
and thus, create the environmental problem. The study involved the experiment to use
the RFS as a coagulant material for settleability improvement in sewage municipal
sludge's treatment and the result is compared to the other commercial coagulants which
are alum (Al2 (804)3), ferrous sulphate (FeS04), and ferric chloride (FeCl3). Apart from
settleability, the study also focused on the RFS efficiency on removal of Chemical
Oxygen Demand (COD), Color, and Total Suspended Solid (TSS) in the leachate
treatment. As a result, RFS proved to be a better coagulant for sludge settleability which
recorded 5.15 cm/min and performance increased by 115%, compared to alum 4.8
cm/min (100% efficiency), FeCl3 3.875 cm/min (62% efficiency), and FeS04 3.75
cm/min (56% efficiency). In leachate treatment, FeCU is the best coagulant in COD
removal since it recorded 68% efficiency, followed by RFS (67% efficiency), alum
(36% efficiency), and FeS04 (20% efficiency). For Color parameter, alum is the best
coagulant since it recorded 90% removal, followed by RFS (88%), FeCl3 (64%), and
FeS04 (27%).