||Ultimate Disposal of Phosphate from Waste Water by Recovery as Fertilizer.
Dunset, Maria G. ;
Salutsk, Murrell L. ;
Rie, Kenneth M. ;
Shapir, Joseph J. ;
||Grace (W.R.) and Co., Chicago, Ill. Dearborn Chemical Div.
||FWQA-14-12-171; FWQA-17070-ESJ; 03459,; 17070-ESJ-01/70
( Water pollution ;
( Precipitation(Chemistry) ;
Phosphorus inorganic acids) ;
( Sewage treatment ;
( Fertilizers ;
Sewage treatment) ;
( Chemical removal(Sewage treatment) ;
Ammonium compounds ;
Magnesium inorganic compounds ;
Calcium phosphates ;
Heat treatment ;
Activated sludge process ;
Ammonium magnesium phosphate
||Some EPA libraries have a fiche copy filed under the call number shown.
||Many of the proposed processes that reduce orthophosphate in the effluents from sewage treatment plants result in the extracted phosphate being concentrated in the digester supernatant. This phosphate must be removed prior to disposal of the supernatant or its recycle back to the head of the treatment plant. Digester supernatant was treated in two ways. The first was to add magnesia and elevate the pH to 9 to cause precipitation of the phosphorus. The other technique was to apply heat and/or vacuum to the digester supernatant which caused precipitation of the soluble orthophosphate. A 90% removal of orthophosphate can be achieved by either approach. The heat and/or vacuum process also yields a supernatant substantially lower in BOD, COD, and nitrogen concentration. The precipitated phosphorus (primarily a mixture of calcium phosphate and magnesium ammonium phosphate) was found available for plant food. Work was conducted by bench and pilot plant studies on digester supernatant.
||Paper copy available from Superintendent of Documents GPO, Washington, D.C. 20402. $0.70 as I67.13/4:17010-ESJ01/70.
|NTIS Title Notes
||Water pollution control research series.
|PUB Date Free Form
||SOD MF A01