In comparison to crude extract and other two ultrafiltration
fraction, the highest coagulation activity of the 2nd fraction was
the lowest one, 45.3%. It was achieved at the highest investigated
pH value, pH 10, which appeared to be the most appropriate
for molecules contained in this fraction to act as turbidity
removing agents. However, at the same conditions, this fraction
exhibited the best performance regarding COD removal (see
Table 1). As for the 3rd fraction containing biomolecules above
30 kDa and having the highest protein concentration, maximum
of coagulation activity was recorded at pH 9.5 with relatively
small volume of fraction added to turbid water, 0.25 mL/L. In
comparison to this result, the highest coagulation activities this
fraction has shown at pH 9 and pH 10 were about 2.4 and 1.4
times lower, respectively, which were achieved at higher dosage,
1 mL/L.