Effect of pH and Natural–Synthetic Coagulant Blends on Turbidity and Color Removal from Moche River Water

The Moche River is currently severely impacted by pollution originating from mining and agricultural activities, which compromises the quality of the water used for various purposes, including irrigation. This study evaluated the effectiveness of natural coagulants derived from Moringa oleifera (moringa) and Caesalpinia spinosa (tara), in combination with polyaluminum chloride (PAC), for improving the removal of turbidity and color from Moche River water. A simplex lattice experimental design comprising 33 trials was employed to assess the effects of different coagulant combinations at pH levels of 5, 7, and 9. The optimal results were achieved with a mixture of 80 ppm moringa and 40 ppm tara, resulting in 95.38% turbidity removal at pH 5 and 91.87% color removal at pH 9. However, the maximum removal achieved using all three coagulants was 77.48% for turbidity with 20 ppm moringa, 20 ppm tara, and 80 ppm PAC at pH 5. For color, the highest removal was 71.01% with 40 ppm moringa, 40 ppm tara, and 40 ppm PAC, also at pH 5.