Fluidized-Bed Process for Phosphate Removal by Calcium Phosphate Crystallization

A new process for the removal of phosphate from effluent from sewage treatment plants is described. The process is based on the crystallization of calcium phosphate in a fluidized bed. The major advantage of the process is the fact that no sludge is produced, but a small quantity of waterfree pellets that can be reused in the phosphate industry. The results of five years of research and development are presented. In 1984 the first demonstration plant will be built. Cost calculations for a full-scale plant are also given.

Download Full-text

A theoretical analysis of the fluidized-bed process for the reduction of iron ores

Chemical Engineering Science ◽

10.1016/0009-2509(90)87118-c ◽

1990 ◽

Vol 45 (5) ◽

pp. 1253-1265 ◽

Cited By ~ 18

Author(s):

N.S. Srinivasan ◽

Staffansson L.-I.

Keyword(s):

Theoretical Analysis ◽

Fluidized Bed ◽

Iron Ores ◽

Reduction Of Iron ◽

Fluidized Bed Process

Download Full-text

Dry reforming of biogas in fluidized bed: Process intensification

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2016.12.124 ◽

2017 ◽

Vol 42 (19) ◽

pp. 13589-13597 ◽

Cited By ~ 24

Author(s):

P. Ugarte ◽

P. Durán ◽

J. Lasobras ◽

J. Soler ◽

M. Menéndez ◽

...

Keyword(s):

Fluidized Bed ◽

Process Intensification ◽

Dry Reforming ◽

Fluidized Bed Process

Download Full-text

Phosphate removal in real anaerobic supernatants: modelling and performance of a fluidized bed reactor

Water Science & Technology ◽

10.2166/wst.1998.0065 ◽

1998 ◽

Vol 38 (1) ◽

pp. 275-283 ◽

Cited By ~ 21

Author(s):

P. Battistoni ◽

P. Pavan ◽

F. Cecchi ◽

J. Mata-Alvarez

Keyword(s):

Fluidized Bed ◽

Contact Time ◽

Fluidized Bed Reactor ◽

Phosphate Removal ◽

Plant Design ◽

Air Stripping ◽

And Performance ◽

Ph Range ◽

Very High ◽

A2o Process

Phosphate removal in anaerobic supernatant coming from a centrifugation sludge station of an A2O process is studied. A fluidized bed reactor is employed to crystallize phosphate as hydroxyapatite or struvite using only air stripping to reach the supersaturation pH. The classic composition of supernatant (alkalinity 3550 mgCaCO3/l, PO4 139 mg/l, Mg 24 mg/l) does not require any addition of chemicals for phosphate removal. Seventeen runs are performed in a bench scale FBR obtaining very high conversion and removal efficiency and phosphate loss in the effluent ≤3.5%. The use of Ca or Mg enriched supernatant has no meaningful influence on efficiency, but it determines the prevalent salt formed between MAP or HAP. Efficiency can be related to pH and sand contact time in a double saturational model. The half efficiency constants: 0.075 h for t and 7.75 pH, have an important role in the process knowledge and optimization of plant design. Exhaust sand analysis indicates the same composition at the top, bottom and mean of the sand bed (39% mol MAP and 61% mol HAP). This result together with the high half efficiency constant for contact time indicate that the phosphate growth on the bed is not competitive. Finally, the phosphate release from the plant is studied. Results show a weak release rate, equivalent to 2.8-10% d−1 phosphate as MAP, obtained at an operative pH range of 8.1-8.4.

Download Full-text