Characterization Of Pectin As Biopolymeric Flocculant And Its Effectiveness In The Treatment Of Turbid Waste Water
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Date
2009-09
Authors
Ho, Yeek Chia
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Coagulation and flocculation processes were applied in the treatment of turbid
wastewater. Two coagulants, namely, Al3+ and Fe3+ and three flocculants, namely,
commercial pectin, industrial flocculant and self-extract pectin from orange peel were
used to compare the effectiveness of the treatments. Response Surface Methodology for
two responses, namely, flocculating activity and turbidity reduction was applied for the
optimization of the treatment conditions. The physicochemical characteristics of the
three flocculants were analyzed. The results showed that the industrial flocculant had the
highest average molecular weight, the longest chain, and were thermally stable when
compared to the commercial and the extracted pectin. The main reactive groups for
pectin were carboxyl and hydroxyl groups while it was the primary amide group for the
industrial flocculant. Response Surface Methodology was used to optimize all sets of
experiments. The optimum treatment conditions for the industrial flocculant was pH
between 7.5 and 8.2, Al3+ concentration between 0.02 mM and 0.05 mM, and industrial
flocculant concentration between 6.5 mg/L and 8.0 mg/L. For the commercial pectin, the
optimum treatment conditions were at pH between 3 and 9, Fe3+ concentration between
0.5 mM and 1.0 mM, and commercial pectin concentration around 3 mg/L. Optimum
treatment conditions for the extracted pectin were pH between 4.6 and 7.5, Al3+
concentration between 0.60 mM and 0.95 mM and extracted pectin concentration
between 4 mg/L and 6 mg/L. When Al3+ was used as a coagulant, the amount of sludge
produced were similar for all of the three flocculants, while the extracted pectin showed
the highest sludge production value followed by the industrial flocculant and the
commercial pectin respectively when Fe3+ was used as a coagulant. The Chemical
Oxygen Demand (COD) of the clarified supernatant was the lowest using the extracted
pectin as a flocculant and Al3+ as a coagulant (COD = 18.3 mg/L), while it was the
highest when the industrial flocculant was applied using Fe3+ as coagulant (COD = 59.0
mg/L).
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Keywords
Coagulation and flocculation processes were applied , in the treatment of turbid wastewater