Application of Ti-salt Coagulant and Sludge Recycling for Phosphorus Removal in Biologically Treated Sewage Effluent

As the regulation of total phosphorus (T-P) concentration in biologically treated sewage effluent is reduced to 0.2 similar to 2 mg/L, flocculation process is recommended to remove T-P. In this study, the performance of Ti-salt coagulant was investigated in terms of dosage and pH in removing phosphorus and the collected sludge after Ti-salt flocculation was calcined to produce titania for effective sludge recycling. The flocculation performance was carried out using two methods: sedimentation and air floatation. Both methods were feasible to apply for Ti-salt flocculation. Ti-salt flocculation was effective in reducing phosphorus concentration in sewage effluent, which showed similar performance of alum (Al-2(SO4)(3)). The calcined sludge was recycled to titania which is the widely used metal oxide. Titania produed from Ti-salt sludge indicated similar charateristics of commercially-available P-25 in regard to photocatalytic activity and surface area. Therefore, this can be easily adopted to titania application by replacing P-25.