A preliminary test of the possibility for reclamation of phosphorus from aquaculture sludge. A CtrlAQUA pre-project

Summary

The concentrations of dissolved phosphates (PO4) and total phosphorus was analysed in sludge samples collected from Nofima’s RAS facilities. The highest concentration of phosphorus was found in sludge from the swirl separators that are mounted at each tank, and most (approximately 90 %) of the phosphorus was bound to particles. Hias IKS has developed a biological method for reclamation of water dissolved phosphorus (PO4) from waste water. This method may be applicable for reclaiming phosphorus from aquacultural sludge. A simple test showed that dissolved phosphorus (PO4) from the water fraction was almost completely removed with Hias’ method in sludge samples of 12 ‰ brackish water. However, since only approximately 10 % of the phosphorus in the sludge was dissolved in the water, pretreatment of the sludge to release dissolved PO4, is necessary for Hias’ method to remove phosphorus from aquacultural sludge effectively.