Phosphorus Recovery from Dehydrated Water Sludge by Incineration Using Alkali Metal Compounds

In order to recover the phosphorus from the waste water sludge,the dehydrated sludge was mixed with the reagent of NaOH,KOH or Na2CO3,and incinerated at 750℃ or 900℃.Phosphorus in the incinerated ash of the sludge was dissolved by the addition of water,and recovered by the evaporation of the phosphorus resolved water.The recovered phosphorus was confirmed to be an alkali metal phosphate,and the recovery rate reached about 75%regardless any combination of the reagents(NaOH,KOH or Na2CO3).