Phosphorus Co-Precipitation in the Biological Treatment of Slaughterhouse Wastewater in a Sequencing Batch Reactor

The effect of phosphorus co-precipitation with ferric chloride ( FeCl3 ) dosing on biological phosphorus (P) along with carbon (C) and nitrogen (N) removal was investigated in a sequencing batch reactor (SBR) for slaughterhouse wastewater treatment. Additional phosphorus removal due to chemical co-precipitation was evaluated as the difference in System P removal between Phase 1 (control—without FeCl3 dosing) and Phase 3 (with FeCl3 dosing). Phase 2 was mainly studied to improve nitrification/denitrification process with acetate addition by Filali-Meknassi et al. in 2004. Both systems (Phases 1 and 3) exhibited high P removal but a co-precipitation with FeCl3 dosing only allowed us to have an orthophosphates (o- PO4 ) concentration below 1 mg P∕L in the effluent. Without FeCl3 addition, the total P concentration was reduced from 85±12 to 14±2 mg P∕L (84% removal), whereas with the addition of FeCl3 an additional 11 mg P∕L was removed bringing the effluent P concentration to 3 mg P∕L (as total P). Although,...