Hydrated calcareous oil-shale ash as potential filter media for phosphorus removal in constructed wetlands
| Autor: | Christina Vohla, Ago Kaasik, Riho Mõtlep, Kalle Kirsimäe, Ülo Mander |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Ettringite
Environmental Engineering Industrial Waste Mineralogy chemistry.chemical_element engineering.material Portlandite Water Purification chemistry.chemical_compound Waste Management and Disposal Dissolution Water Science and Technology Civil and Structural Engineering Ecological Modeling Phosphorus Sediment Sorption Phosphate Pollution chemistry Wetlands Environmental chemistry engineering Adsorption Calcareous Filtration Fuel Oils Water Pollutants Chemical Power Plants |
| Zdroj: | Water Research. 42:1315-1323 |
| ISSN: | 0043-1354 |
| DOI: | 10.1016/j.watres.2007.10.002 |
| Popis: | The P-retention in hydrated calcareous ash sediment from oil-shale burning thermal power plants in Estonia was studied. Batch experiments indicate good (up to 65 mg P g(-1)) P-binding capacity of the hydrated oil-shale ash sediment, with a removal effectiveness of 67-85%. The high phosphorus sorption potential of hydrated oil-shale ash is considered to be due to the high content of reactive Ca-minerals, of which ettringite Ca6Al2(SO4)3(OH)12.26H2O and portlandite Ca(OH)2 are the most important. The equilibrium dissolution of ettringite provides free calcium ions that act as stable nuclei for phosphate precipitation. The precipitation mechanism of phosphorus removal in hydrated ash plateau sediment is suggested by Ca-phosphate formation in batch experiments at different P-loadings. Treatment with a P-containing solution causes partial-to-complete dissolution of ettringite and portlandite, and precipitation of Ca-carbonate and Ca-phosphate phases, which was confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM)-EDS studies. Thus, the hydrated oil-shale ash sediment can be considered as a potential filtration material for P removal in constructed wetlands for wastewater treatment. |
| Databáze: | OpenAIRE |
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