Flocculation Behavior in Hexagonal-Hole Grid System Dealing with High Turbidity Water

The hexagonal-hole grid flocculation system is very efficient to deal with high turbidity water of 850 NTU and the color of 2300 PCU. The best conditions are determined through adjusting grid arrangements, concentration and dosage of flocculating agent. When the water velocity of flow is 100 L/h, the grid 2, 1, 3 module order is the best one. The water turbidity decreased to 19.5 NTU and color to 110 PCU, the removal rate of turbidity is 97.0% and that of color is 95.2%. The average effective mass density ρ_e of floc is 6066 Kg·m^-3, the average equivalent size d_ST is 346.9μm, the average free-for-speed V is 13.24 mm·s^-1, two-dimensional fractal dimension D_f is 2.70.