poster - International Conference of Agricultural Engineering

in a grinder and passed through a 0.84 mm sieve opening. To the resulting powder was
added distilled deionized water at 2% w / v. The suspension was homogenized by a
magnetic stirrer for 3 min and passed through a 0.125 mm sieve opening, resulting in the
coagulant solution used in the experiments.
The determination of the dose of powdered seed to fill the pouches was made from
the correlation between the protein content of the coagulant in solution and in pouches in the
dispersing stage. Arantes (2010) recommends a dose of 10 ml L -1 of coagulant solution (2%)
for a 65 NTU turbidity value. This dosage was adopted when the coagulant solution was
used and as a reference for the calculation of the doses of powdered seed to be added in the
pouch.
2.2.3 Clarification process
From the assays of dissolution of protein in distilled water, it was used the period of
30 min to dissolve the protein with a gradient velocity of 10 s -1 during the clarification stage.
Three different doses of Moringa oleifera powdered seeds in the pouches and one dosage of
the coagulant solution were studied.
After dissolution of the protein (only for the pouches) coagulation (30 s at a velocity
gradient 400 s -1 ) and flocculation (10 min at 20 s -1 ) were carried out. Sedimentation took
place for 60 min, and samples were collected at 0, 5, 15, 30, 45 and 60 min. Turbidity and
apparent color parameters were determined according to the Standard Methods (APHA,
2005).
3. RESULTS AND DISCUSSION
3.1. Tests for protein dissolution
Table 1 shows that, for each time over 24 h, the turbidity values for the five pouches
were statistically equal (A), differing from the direct application of the powdered seed of
Moringa oleifera in distilled water (B), when such values were higher. When each pouch is
studied over time, the one made of filter paper shows a significant variation in turbidity value
only after 20 h, while in the other pouches such change occurs earlier (120 min for the
stitched non-woven fabric and 240 min for pouches made of white, black and gray fabrics).
Table 2 shows that the protein content values were statistically equal for the 5
pouches studied and the direct application of the powder from 60 min to 24 h period. The
analysis of the individual pouch over time shows significant differences in protein content
after 30 min for the stitched non-woven fabric and filter paper pouches. For the other
pouches, significant differences occurred after 60 min.
According to the protein content of the coagulant solution of Moringa oleifera the
suitable pouch must release about 21.33 mg of protein per liter of turbid water. All 2 g
pouches provided higher content of protein than the required for 30 min of dispersion. The
paper pouch was better for the clarification of synthetic turbid water, once it presented
convenience of manufacture and availability and took longer to show an increased turbidity
over the 24 h.