Removal and recovery of phosphorus in wastewater by superconducting high gradient magnetic separation with ferromagnetic adsorbent

Abstract

Prevention of eutrophication for semi-enclosed bays and ponds is serious and important challenge. In spite of the advanced wastewater treatment, typically 1mg/L phosphorus is discharged into public water bodies from wastewater treatment plants. The total amount of the discharged water is so large that the further improvement of the removal efficiency of phosphorus in the discharged water is demanded. On the other hand, recently phosphorus has become increasingly recognized as the important strategic material due to the global food problem. Therefore, the recovery and recycling of phosphorus is also important issue.In this work, removal and recovery of phosphorus from treated wastewater by High Gradient Magnetic Separation (HGMS) with ferromagnetic zirconium ferrite adsorbent were studied. Phosphorus in the treated wastewater could be removed from 1.12mg/L to 0.03mg/L by the HGMS system with 500mg/L zirconium ferrite adsorbent for 5min in adsorption time. The magnetic separation speed achieved 1m/s at 1T which was necessary for practical use. We also confirmed that phosphorus could be desorbed from zirconium ferrite adsorbent by alkali treatment in a short time.