The Scientific World Journal / 2012 / Article / Tab 3 / Research Article
Optimization of Ozonation Process for the Reduction of Excess Sludge
Production from Activated Sludge Process of Sago Industry Wastewater Using Central Composite Design Table 3 The design matrix and observed values of the central composite design.
Run Variables in uncoded levels pH
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1
Ozonation time
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2
Retention time
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VSS reduction % (
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) COD reduction % (
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)
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(%) (%) (%) (%) 1 7 10.5 5.5 75.12 76.31 85.40 86.17 2 10 10.03 5.5 50.39 50.98 74.80 74.69 3 8.8 16.1 2.8 44.77 40.60 67.50 73.30 4 5.2 4.9 8.2 96.59 99.93 86.00 87.12 5 7 10.5 5.5 76.42 76.31 65.00 68.89 6 7 10.5 5.5 76.35 76.31 86.30 86.17 7 7 10.5 5.5 76.79 76.31 86.40 86.17 8 7 10.5 5.5 76.79 76.31 86.10 86.17 9 8.8 4.9 8.2 60.40 53.91 53.40 59.95 10 3.97 10.5 5.5 60.51 59.39 65.00 62.56 11 7 10.5 10.4 89.22 87.19 80.40 89.30 12 7 10.5 0.96 21.18 26.31 40.40 49.40 13 8.8 16.1 8.2 86.80 82.99 64.50 66.66 14 5.2 16.1 2.8 76.78 76.31 85.00 83.31 15 8.8 4.9 2.8 93.18 89.44 63.19 65.78 16 5.2 16.1 8.2 96.26 97.29 80.70 80.63 17 7 19.92 5.5 76.24 76.07 64.00 56.03 18 5.2 4.9 2.8 59.41 67.66 80.40 75.59 19 7 1.08 5.5 47.58 46.31 63.20 63.42 20 7 10.5 5.5 76.79 76.31 86.40 86.17
