Combined Application of Coagulation/Flocculation/Sedimentation and Membrane Separation for the Treatment of Laundry Wastewater

Table 4

Doehlert design matrix and removal of color and turbidity of the wastewater (batch 1) using the Tanfloc POP® coagulant.

Run	Level pH	pH	Level concentration	Concentration (mg L^−1)	Color (%)	Turbidity (%)
1	−1	4.6	0	120	90.83 ± 0.2	94.24 ± 1.7
2	−0.5	5.5	0.8	180	62.33 ± 1.0	70.14 ± 2.8
3	−0.5	5.5	−0.8	60	88.37 ± 5.0	88.56 ± 6.3
4	0	6.3	0	120	91.09 ± 2.1	94.34 ± 4.6
5	0	6.3	0	120	91.85 ± 1.3	94.23 ± 1.3
6	0	6.3	0	120	93.91 ± 1.6	93.12 ± 2.8
7	0.5	7.2	−0.8	60	53.88 ± 5.9	59.70 ± 8.7
8	0.5	7.2	0.8	180	89.67 ± 0.1	94.23 ± 1.3
9	1	8.0	0	120	81.75 ± 4.3	82.74 ± 1.9

Operating conditions: 2 minutes of rapid mixing (120 rpm), 15 minutes of slow mixing (20 rpm), and 10 minutes of sedimentation.