Modified Diatomaceous Earth for Sludge Settlement Amelioration

Diatomaceous earth (DE) was modified with chemicals, which were composed of ferric chloride, aluminium sulfate and aluminium polychlorid on the base of mass fraction of 1: 5: 5 and named mixed coagulant (MC) herein, and used for waste sludge conditioning for the purpose of improving sludge settling performance and supernatant suspended solid (SS) removal. The results showed that sludge velocity (SV) decreased with modified diatomaceous earth (MDE) dosage increase, MDE brought in the highest 72% of sludge supernatant SS removal. From technical and economical points of view, the optimum dosage of MDE is 0.2 g DE and 0.33 g MC per liter waste sludge.