title: Active filtration of phosphorus on Ca-rich hydrated oil shale ash: does longer retention time improve the process?
abstract: The purpose of this research was to investigate the phosphorus binding capacity of active filtration through hydrated Ca-rich oil shale ash sediment in a laboratory-scale experiment at different retention times. Three column experiments were established with hydraulic loading rates of 12 L d(-1), 18 L d(-1), and 24 L d(-1), with residence times of 12, 8, and 6 h, respectively. The results showed good removal efficiency (up to 91% at loading of 1.66 gP m(-2) d(-1)) in the experiment with the longest retention time. The overall performance of the filters did not, however, improve with increasing retention time, and the decrease in binding capacity was 41% at longer retention times. Chemical clogging by carbonate precipitates probably reduces the availability of Ca from the dissolution of unstable ash sediment mineral phases, and the phosphate removal decreases rapidly from 91% to 49% at loading of 1.66 gP m(-2) d(-1).
authors: Department of Geology, University of Tartu, Vanemuise 46, Tartu, Estonia. liira@ut.ee
authors: Martin
authors: M
authors: Liira
authors: Margit
authors: M
authors: Kõiv
authors: Ulo
authors: U
authors: Mander
authors: Riho
authors: R
authors: Mõtlep
authors: Christina
authors: C
authors: Vohla
authors: Kalle
authors: K
authors: Kirsimät
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry; D011232:Chemical Precipitation; D003460:Crystallization; D005374:Filtration / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D009821:Oils / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D010758:Phosphorus / Q000302:isolation & purification*; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D009821:Oils; D010710:Phosphates; D014867:Water; D010758:Phosphorus; D002119:Calcium Carbonate; D002118:Calcium