Noram Engineering and Constructors Ltd.

J Ming Zhuang

Anthony S Walsh

A method for removing metals from metal-containing acidic mine wastewater uses a basic sludge produced by the method for treating the wastewater. The wastewater is mixed with a lime slurry and with the basic sludge. This mixture is allowed to separate into an aqueous effluent and an acidic sludge. The effluent is mixed with the lime slurry and with a composition containing an iron compound, to produce a mixture. This mixture is allowed to separate into an aqueous effluent and the basic sludge. Lignin derivatives, such as calcium lignosulfonate, may be included in the treatment mixture.

Method for treating acidic waters using recycled acidic and basic sludges

A method for removing metal contaminants from water uses lignin derivatives, such as lignosulfonates and kraft lignin, a coagulant, such as a metal salt, and a pH-increasing composition. The lignin derivative is dispersed in the contaminated water, the coagulant is added and the pH is adjusted as required to cause flocculation. A sludge is formed that contains the metals and that is separated from the treated water by filtration. Related methods are used to reduce the leachable metal content of contaminated soils. The invention also provides a composition for stabilizing the metal contaminants in soil, comprising lignin derivatives, a coagulant and a composition for increasing the pH. The mixture is blended with the contaminated soil, reducing its leachable metal content.

Method for treating metal-contaminated water and soil

A method for removing metal contaminants from acidic mine wastewater using lignin derivatives, such as lignosulfonates and kraft lignin, an alkali coagulant, such as a lime compound, and an alkaline composition for increasing the pH. The lignin derivatives are dispersed in the wastewater and the coagulant is added, increasing the pH to about 4.5&#x2013;8.5 and causing the formation of a floc. The alkaline composition is then added to bring the pH to about 9 to 10, causing the further formation of a floc. Optionally, air oxidation is carried out, reducing the pH to about 8.1&#x2013;8.6. Optionally, a ferric or ferrous salt may also be added. The flocs comprise metal-lignin colloids, metal hydroxides and metal salts. The flocs coagulate to form a sludge. Optionally, fly ash or diatomaceous earth may be added to increase the density and stability of the sludge. The sludge that is formed contains the metals and is separated from the treated water by filtration.

Growing community of inventors

Coquitlam, Canada

J Ming Zhuang