Optimization of tanfloc and PAC dosages for phosphorus removal in primary sewage treatment

Jar tests were performed in 1 L volumes, with a mixing configuration of 2 min of rapid mixing at 100 rpm, 20 min of slow mixing at 30 rpm, and a sedimentation time of 30 min. Preliminarily, the use of tanfloc (10-150 mg/L) and PAC (10-300 mg/L) were evaluated separately.

Subsequently, a central composite rotational design (CCRD) was performed for the combination of tanfloc (factor X1) and PAC (factor X2). pH, turbidity, color, COD, total phosphorus, and total suspended solids (TSS) were evaluated according to Standard Methods (APHA, 2012).