Chitosan, the de-acetylated chitin derivative, was evaluated for its ability to be used as a coagulant for Martapura groundwater treatment. This study is used chitosan derived from original fish scales of Kalimantan called Papuyu (Anabas testudineus) for the treatment of iron ion-containing Martapura groundwater throught coagulation-flocculation method. The reduction efficiency of iron ion removed by coagulation-flocculation processes using chitosan from Papuyu fish scales is the main evaluating parameter. The obtained chitosan have been characterized and analyzed by Fourier transforms infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). Using of the chitosan from Papuyu fish scales as coagulant at neutral pH and room temperature led to decreasing the groundwater iron concentration become 3.43 mg/L (around 71% removal). The result was then compare to the coagulation-flocculation treatment using the commercial chitosan from shrimps shell (93% deacetylated). Moreover, its found the coagulation-flocculation treatment using the chitosan from fish scales as coagulant more favor than the commercial one.
