The University of Waterloo

David W Blowes

Carol J Ptacek

Michael John Baker

The metal oxide media includes oxides and hydroxides of iron, and other metals. The material is derived from basic-oxygen steel-making process, and includes a high calcium content. The oxide surfaces facilitate the adsorption of phosphorus, and the increased pH facilitates the precipitation of calcium and other phosphates. The oxides are a catalyst for converting organic phosphorus to inorganic form. Limestone may be added to the oxides, to ensure a long-term source of calcium, and to maintain high pH for long periods.

Treatment of contaminated water

A system for treating groundwater contaminated with acidity or other contaminants is disclosed. The system involves excavating a trench into the aquifer in the path of the contaminant plume, and placing a body of active material in the trench. The active material depends on the particular contaminant: organic carbon may be used when the contaminant is ferrous sulphate, or hexavalent uranium oxide, or dissolved nitrate; pyrite or elemental iron may be used when the contaminant is eg chromium oxide. The active material causes the contaminant, by chemical reaction, to change its oxidation-reduction state, and to precipitate harmlessly in the body of material.

System for treating contaminated groundwater

A system for treating groundwater contaminated with acidity or other contaminants is disclosed. The system involves excavating a trench into the aquifer in the path of the contaminant plume, and placing a body of active material in the trench. The active material depends on the particular contaminant: organic carbon may be used when the contaminant is ferrous sulphate, or hexavalent uranium oxide, or dissolved nitrate; pyrite or elemental iron may be used when the contaminant is e.g. chromium oxide. The active material causes the contaminant to transform or break down by chemical reaction into harmless precipitates and substances.

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Waterloo, Canada

David W Blowes