Full Scale Optimization of Flocs Blanket Process Applied in Ferric Flocs Sludge Treatment

Abstract

The flocs blanket process is a traditional technology for high concentration suspensions removal. In this paper, by thickening ferric flocs sludge, the flocs blanket process was optimized with a scale of 19~38 m3/H to achieve more satisfied operational condition. Under the raw sludge concentration of 100~1200 mg/L, an increase in polymer dosage would improve outlet turbidity, the moderate mechanical agitating strength of 3 rpm could achieve best operational results. The experimental results also revealed an approximately linear relationship between raw water concentration and optimum PAM dosage, that is, the optimum dosage of PAM increased synchronously with the increasing raw sludge concentration. While the relationship between raw sludge concentration and maximum up-flow rate reflected negatively linear dependence, the maximum up-flow rate would decrease linearly with the increasing raw sludge concentration. The experimental results proved that the flocs blanket process could be applied to thicken the ferric flocs sludge as a highly efficient technology.