poster - International Conference of Agricultural Engineering

3.2. Determination of the required dose of powdered seeds in the pouches
Considering jars of 2 L capacity, it would take 20 mL of 2% coagulant solution for
each 2 L jar for 65 NTU turbidity values (ARANTES, 2010). Based on the protein content of
the coagulant solution and the recommended dosage, each pouch must provide the
equivalent of 42.66 mg of protein. Once the average protein content of the paper pouch with
2 g of powder is 112.15 mg L -1 in 30 min of dispersion time and assuming that the
relationship between protein content and powder dose is directly proportional, the powder
dosing in each pouch must be approximately 0.76 g.
Therefore, the doses of powdered seeds of Moringa oleifera in the pouches were 0.6
g, 0.8 g and 1.0 g in the clarification tests.
3.3. Clarification of synthetic turbid water
The average results for turbidity and apparent color of the turbid synthetic water are
shown in Tables 3 and 4, respectively. The results of Scott-Knott test with 5% significance
concerning the comparisons for each dosage over time and between the dosages for each
time are also shown.
TABLE 3: Mean values of turbidity during the sedimentation and result of Scott-Knott test
with 5% significance (*). Raw water turbidity = 65.5 NTU.
Dosage
Time (min)
0 5 15 30 45 60
10 mL L -1 ** 89.10 A b 9.42 A a 2.94 A a 2.00 A a 1.61 A a 1.37 A a
Pouch 0,6 g 78.30 A b 30.23 B a 25.00 B a 23.90 B a 23.53 B a 23.37 B a
Pouch 0,8 g 81.97 A b 14.00 A a 12.59 A a 11.91 A a 11.51 A a 11.38 A a
Pouch 1,0 g 85.77 A c 26.00 B b 4.99 A a 2.70 A a 2.07 A a 1.71 A a
(*) The same lowercase letters should be interpreted as statistical similarity of data in line. The same
capital letters should be interpreted as statistical similarity of the data in column. (**) Coagulant
solution.
TABLE 4: Mean values of apparent color during the sedimentation and result Scott-Knott
test with 5% significance (*). Apparent color of the raw water = 316 mg Pt-Co L -1 .
Dosage
Time (min)
0 5 15 30 45 60
10 mL L -1 ** 419.00 A b 42.00 A a 11.00 A a 6.00 A a 4.00 A a 3.00 A a
Pouch 0,6 g 361.67 A b 124.67 B a 98.67 B a 91.33 B a 90.00 B a 88.67 B a
Pouch 0,8 g 372.00 A b 69.00 A a 47.33 A a 44.67 A a 42.67 A a 42.00 A a
Pouch 1,0 g 397.33 A c 120.67 B b 23.00 A a 11.67 A a 9.00 A a 7.00 A a
(*) The same lowercase letters should be interpreted as statistical similarity of data in line. The same
capital letters should be interpreted as statistical similarity of the data in column. (**) Coagulant
solution.
The statistical analysis of Tables 3 and 4 showed significant reductions of apparent
color and turbidity in the initial 5 min for the coagulant solution and the powder pouches of
0.6 and 0.8 g, with stability after this period until the end of sedimentation. The 1.0 g pouch
presented significant difference with subsequent stabilization only after 15 min of
sedimentation. After this period of sedimentation (when the turbidity and apparent color
values did not vary over time for the 4 treatments), the comparison of dosages at each time
demonstrates that the coagulant solution and the pouches of 0, 8 and 1.0 g did not differ.
The 0.6 g pouch differs from the others and presented less reduction in the evaluated
parameters.
At the end of sedimentation (60 min), the efficiency of turbidity reduction compared to
the raw water was 97.9%, 64.3%, 82.6% and 97.4% for the coagulant solution and pouches