2.5. Jar Test procedures on kaolin clarification
Jar Tests were used to evaluate the flocculating efficiency of the
bio-flocculants in clarification of kaolin slurry and were conducted
with a commercially available Jar Tester (ET 720, Lovibond, Germany)
at room temperature. The kaolin suspension was used as a
representative colloidal material because its surface characteristics
are well-understood and is commonly used to evaluate the characteristics
of newly developed flocculants (Lee et al., 2010; Yang
et al., 2009).The bio-flocculant was injected into kaolin slurry whilst stirring
at 700 rpm. The flocculation process consisted of stirring at
700 rpm for 1 min, followed by stirring at 350 rpm for 1 min and
settling for 30 min. The settled sludge volume was taken for
calculation of the sludge volume index (SVI) according to Method
2710D (Rice et al., 2012). The supernatant was used for measurement
of the SS and TU. The treated solutionwas then subjected to a
filtration test to analyse the sludge dewatering ability.