||Phosphate Removal from Waste Waters Using Lanthanum Precipitation.
Rech, Howard L. ;
Ghassem, Masood ;
||Atomics International, Canoga Park, Calif.
||FWQA-14-12-183; FWQA-17010-EFX; 03458,; 17010-EFX-04/70
( Water pollution ;
( Sewage treatment ;
( Precipitation(Chemistry) ;
Phosphorus inorganic acids) ;
( Lanthanum ;
Sewage treatment) ;
Chemical removal(Sewage treatment) ;
||Some EPA libraries have a fiche copy filed under the call number shown.
||A parametric study was made of the removal of ortho- and polyphosphates from pure solutions and secondary effluent with La(III), and the results compared with those from similar tests with Al(III). The reactions of orthophosphate with both La(III) and Al(III), resulting in precipitate formation and phosphate removal, were complete in less than 1 sec. La(III) showed a broader effective pH range and lower residual phosphate concentration and thus proved to be far superior to Al(III) for phosphate, especially polyphosphate, precipitation. Within the pH range for optimal phosphate removal, the La(III)-phosphate reactions produced large, settleable flocs. Immediately outside this range, poorly settling fine turbidity developed. At pH levels above this region, some residual turbidity was generally observed. No turbidity or precipitation was observed at very low pH levels. The results suggest that orthophosphate removal with La(III) occurs solely through a chemical reaction and not through an adsorption process. With secondary effluent, as with pure solutions, lower residual phosphate resulted over a wider pH range with La(III) than with Al(III); no pH adjustment is needed for effective removal with La(III), while considerable amounts of acid or excess Al(III) are required to achieve the optimum pH of 6 for phosphate removal. (WRSIC abstract)
||Paper copy available from Superintendent of Documents, GPO, Washington, D.C. 20402. $0.55 as 167.13/4: 17010-EFX-04-70.
|NTIS Title Notes
||Water pollution control research series.
|PUB Date Free Form
||SOD MF A01