The University of Waterloo

Carol J Ptacek

David W Blowes

William Dean Robertson

Michael John Baker

David W Blowers

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.

Nitrate-polluted run-off water from a field is conveyed via land drains to a reservoir. The reservoir is large enough to contain excess quantities of storm water from the field. From the reservoir, the run-off water enters a tank which contains wood or other organic carbon material. The wood is kept under water, i.e. under anaerobic conditions, whereby the nitrate is broken down by bio-chemical action. Sufficient wood is provided, and the flow rate is so adjusted, that the nitrate-polluted water spends many hours in contact with the wood.

Growing community of inventors

Waterloo, Canada

Carol J Ptacek