CD Skripsi
Pengaruh Variasi Dosis Koagulan Kacang Hijau (Vigna Radiata) Pada Proses Pengolahan Lengkap Air Sungai Siak Terhadap Potensi Pembentukan Trihalometan (Thm)
ABSTRACT
The Siak River, a source of raw water for Pekanbaru City Water Company, contains
organic matter content and high water color. Organic matter content in river water
will produce THM when disinfected with chlorine, so it is necessary to treat organic
matter before disinfection. This study aims to calculate the efficiency of organic
matter and color removal and determine the optimal dosage of mung bean
coagulant to reduce the potential for THM formation. The research method uses a
complete treatment process of coagulation-flocculation, sedimentation, filtration,
and disinfection with variations in mung bean coagulant dosage of 4 g/L, 4.5 g/L,
5 g/L, 5.5 g/L, 6 g/L, and 6.5 g/L. Samples were taken from the intake of the
Pekanbaru PDAM. Coagulation was carried out at pH 3, rapid stirring at 100 rpm
for 1 minute, slow stirring at 40 rpm for 20 minutes, sedimentation for 15 minutes,
quartz sand-gravel filtration, and chlorine disinfection at 2.25 ppm. Analysis using
SNI standards and UV-Vis spectrophotometer with Stephanie regression equation.
The results showed the highest organic matter removal efficiency of 79.94% at a
dose of 5.5 g/L decreased from 23.93 mg/L to 4.80 mg/L. The highest color removal
efficiency of 99.31% at a dose of 4 g/L decreased from 435 PtCo to 3 PtCo.
However, the potential for THM formation was still high with the lowest value of
258.65 μg/L at a dose of 5.5 g/L, exceeding the international THM standard.
Keywords : River water, natural coagulant, mung beans, trihalomethanes, water
treatment
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