Intergraded Applied Methodology for the Treatment of Heavy Polluted Waste Waters from Olive Oil Industries

Table 4

Percent COD removal efficiency results of the factorial experiment.

Trial	𝑋1	𝑋2	𝑋3	𝑋4	% COD efficiency in OMW-DF	% COD efficiency in OMW-DL	% COD efficiency in OMW-DP
(1)	+	+	+	+	67.06	64.90	63.65
(2)	−	+	+	+	60.14	60.92	59.75
(3)	+	−	+	+	67.68	65.52	64.26
(4)	−	−	+	+	54.67	55.38	54.32
(5)	+	+	−	+	64.37	65.21	63.95
(6)	−	+	−	+	61.37	62.17	60.97
(7)	+	−	−	+	65.53	66.38	65.10
(8)	−	−	−	+	69.53	70.39	68.10
(9)	+	+	+	−	69.37	68.22	64.95
(10)	−	+	+	−	63.76	64.58	63.34
(11)	+	−	+	−	64.83	65.68	64.41
(12)	−	−	+	−	62.99	63.80	62.58
(13)	+	+	−	−	64.99	65.83	64.57
(14)	−	+	−	−	61.83	62.63	61.43
(15)	+	−	−	−	66.45	67.31	66.02
(16)	−	−	−	−	64.30	65.13	63.88
(17)	0	0	0	0	63.37	64.19	62.96
(18)	0	0	0	0	63.91	64.74	63.50
(19)	0	0	0	0	63.68	64.51	63.27
(20)	0	0	0	0	64.37	65.21	63.95

COD: chemical oxygen demand.