An article in Journal of Hazardous Materials [Statistical Factor-Screening and Optimization in Slurry Phase Bioremediation of 2,4,6-trinitrotoluene

An article in Journal of Hazardous Materials [€œStatistical Factor-Screening and Optimization in Slurry Phase Bioremediation of 2,4,6-trinitrotoluene Contaminated Soil,€ (2011, Vol. 188(1), pp. 1€“9)] described an experiment to optimize the removal of TNT 2,4,6-trinitrotoluene (TNT). TNT is a predominant contaminant at ammunition plants, testing facilities and military zones. TNT removal (TR) is measured by the percentage of the initial concentration removed (mg/ kg-soil). A 2^7ˆ’3fractional factorial design was conducted. The data are in the following table. Rows below the horizontal line in the table (coded with zeros) correspond to center points.

(a) What is the alias structure of this design?

(b) What is the resolution of this design?

(c) Analyze factor effects and comment on important effects.

(d) Develop a regression model to predict removal in terms of the actual factor levels.

(e) Does a residual analysis indicate any problems?

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NH.CI (g/L) Yeast (g/L) Glucose Tween80 Slurry (g/ml) Temp ('C) Inoculum (g/L) (g/L) A (vol. %) Run D E TR 0.1 1 2 5 20 35 0.2 10 90.5 0.1 5 20 20 0.2 5 80.1 2. 0.1 35 10 92.3 82.9 0.1 5 40 35 5 4 0.1 2 1 40 20 0.2 10 68.1 0.5 20 20 0.2 10 90.4 2 0.5 40 35 10 71.6 0.1 40 35 0.2 5 79.5 0.5 5 40 35 0.2 10 86.5 10 2 0.5 40 20 0.2 5 84.1 11 0.5 5 20 35 5 91.3 12 2 0.5 1 20 35 0.2 5 89.7 13 0.5 40 20 5 78.1 0.1 14 20 20 5 90.4 15 0.5 5 20 20 10 91 0.1 16 40 20 10 83.6 17 0.3 3 30 27.5 0.1 7.5 85.6 0.1 18 5 0.3 30 27.5 7.5 89.7 0.1 19 5 0.3 3 30 27.5 7.5 88.3 2.