Fluoride concentrations in the Montreal Urban Community's untreated wastewater were analyzed in an attempt to evaluate their levels and seasonal variations. Continual hourly monitoring of the raw sewage, between June 1992 and May 1993. yielded average monthly fluoride concentrations between 0.072 mg/L and 1.984 mg/L, with an annual mean of 0.45 mg/L. Daily variations and frequency distributions showed a wider range of fluoride levels, with the maximum values possibly reaching as high as 4-fold the mean and well over 2 orders of magnitude higher than the minimum values. This suggests that significant massive point discharges occur in the sewer network. Daily monitoring of the precipitation showed that the mean fluoride concentration in liquid precipitation generally fluctuates between 0.030 mg/L and 0.741 mg/L, whereas the average fluoride specific mass in dry precipitation ranges between 0.096 kg/km$ sp2$ and 2.775 kg/km$ sp2$. Seasonal trends have been depicted for fluoride levels in both the raw wastewater and the precipitation. Groundwater sampling yielded an average fluoride concentration of 0.13 mg/L, and analysis of the melting salts used by the City revealed that these do not contain any fluoride. Data from the City's water treatment plants showed that the average fluoride concentration in their raw water is 0.20 mg/L. This is in contrast to the value of 0.13 mg/L used in the literature. Mass balance analyses have shown that the mass of fluoride resulting from infiltration and non-fluoridated waters, as well as that due to the domestic habits of the population constitute, among the identified sources, the major input of fluoride mass into the wastewater. Nevertheless, unidentified sources of fluoride, consisting essentially of industrial discharges, still account for the largest portion (${ approx50 %}$ of the total) and contribute, as an annual average, 375 kg/day.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.69788 |
| Date | January 1993 |
| Creators | Choueiri, Najla F. |
| Contributors | Gehr, R. (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: 001397715, proquestno: AAIMM94262, Theses scanned by UMI/ProQuest. |
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