Table 3.

ANOVA for the decolourization and COD reduction of textile dye wastewater

Source	% Decolourization			% COD reduction
	Coefficient factor	F	P > F	Coefficient factor	F	P > F
Model	69.78	19.79	<0.0001	78.72	34.04	<0.0001
A	−0.13	0.017	0.8990	0.092	0.014	0.9074
B	−1.54	2.23	0.1572	−0.76	0.96	0.3440
C	2.30	4.97	0.0426	3.48	20.24	0.0005
D	14.56	199.24	<0.0001	14.30	341.09	<0.0001
A × A	−8.16	33.84	<0.0001	−10.44	98.26	<0.0001
B × B	−4.10	8.54	0.0112	−1.91	3.30	0.0906
C × C	−0.36	0.066	0.8008	−2.55	5.87	0.0295
D × D	−6.95	24.53	0.0002	−4.10	15.17	0.0016
A × B	1.68	0.88	0.3643	0.75	0.31	0.5848
A × C	−1.50	0.71	0.4152	−2.00	2.22	0.1581
A × D	−2.13	1.42	0.2540	−2.68	3.98	0.0659
B × C	2.28	1.62	0.2236	2.55	3.62	0.0780
B × D	−6.28	12.34	0.0034	−0.68	0.25	0.6226
C × D	−0.075	1.73E−003	0.9671	−1.40	1.09	0.3142
R 2	0.9519			0.9715
Pred R2	0.9038			0.9429
Adj R2	0.8240			0.8357
Std. Dev.	3.5700			2.6800
C.V	5.79 %			3.79 %
Adeq precision	16.730			21.429