Table 4.

Design of experimental runs using the Box-Behnken design.

Run order	Polarity reversal, A (hr)	Voltage gradient, B (V/cm)	Concentration, C (mg/kg)	Remedial efficiency, %
1	0	0.6	20	0.00
2	48	0.6	20	0.00
3	24	1	20	0.00
4	24	1	100	0.00
5	24	0.6	60	79.97
6	0	1	60	72.73
7	24	0.2	20	0.00
8	0	0.2	60	36.93
9	48	1	60	65.66
10	48	0.6	100	0.00
11	0	0.6	100	25.50
12	24	0.2	100	0.00
13	48	0.2	60	34.88