Within the scope of a project funded by the Quebec Ministry of the Environment and Fauna (MEF), alternative wastewater phosphorus removal methods to alum or ferric chloride coagulation were assessed. The most promising technologies were found to be enhanced biological phosphorus removal, treatment plant process optimization and on-line process control. The use of alum sludges from potable water treatment plants appeared promising although it has not yet been widely practised or studied. The MEF therefore decided to retain the process as one requiring further study. / Through batch sorption tests with synthetic solutions, it was found that aluminum hydroxide has a significant sorptive capacity for orthophosphate, condensed phosphate and organic phosphate. The removal of these phosphates was independent of pH between pH 3 and pH 6. The solubility of the aluminum hydroxide was highly pH-dependent. In all the tests, except that with organic phosphate at pH 3.6, the measured soluble aluminum was consistent with solutions saturated with solid-phase Al(OH)$ sb3$. With organic phosphate at pH 3.6, an aluminum-organic phosphate appears to have formed. A theoretical analysis of Al(OH)$ sb3$ and Al(PO$ sb4)$ precipitation showed that phosphate removal is not achieved through Al(PO$ sb4)$ precipitation when dosing with conventional alum, but rather that a mixed aluminum hydroxide phosphate precipitate is formed. / Jar tests performed with full-scale alum sludge and wastewater showed that phosphate is removed by the particulate fraction of the sludge. The removal of reactive phosphate (orthophosphate) decreased with an increase in the storage time of the alum sludge. This decrease was not seen with the non-reactive phosphate. It was therefore suggested that reactive phosphate removal is carried out by adsorption and that non-reactive phosphate removal is performed by a sweep-floc mechanism. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.23261 |
| Date | January 1995 |
| Creators | Galarneau, Elisabeth |
| Contributors | Gehr, Ronald (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Civil Engineering and Applied Mechanics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001474886, proquestno: MM07977, Theses scanned by UMI/ProQuest. |
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