Rmt Limited

Other

Robert R Stanforth

Ajit K Chowdhury

A method of treating arsenic-contaminated matter using an aluminum compound in conjunction with an alkaline buffer, thereby stabilizing the arsenic contained in the contaminated matter and decreasing leaching ability. Preferably, the aluminum compound is a soluble aluminum salt such as aluminum sulfate and the alkaline buffer is magnesium oxide.

Method of treating arsenic-contaminated matter using aluminum compounds

A method of treating solid waste in soil or solid disposed waste containing unacceptable levels of leachable metals, such as lead, cadmium, arsenic, zinc, copper and chromium, includes mixing the solid waste or soil in place with a phosphate source or a carbonate source or ferrous sulfate. After the solid waste and the additive are mixed, if needed an additional pH controlling agent is mixed into the soil or waste and additive. After the solid waste and additive and pH controlling agent are mixed under conditions which support reaction between the additive, pH controlling agent and metals, the metals will be converted to non-leachable forms which are relatively stable under normal environmental conditions. The treatment additives can be introduced and contacted with the soil or waste in any of the following techniques: spreading the additives on top of the soil or waste and mixing with a mechanical device, such as a rotary tiller, adding the treatment chemical through an infiltration gallery as a solution or slurry, injecting a soluble additive through injection nozzles or injection wells, and adding a treatment additive through a hollow-shaft auger and in-place mechanical mixing.

In situ method for decreasing heavy metal leaching from soil or waste

A method of treating solid hazardous wastes containing unacceptable levels of leachable metals such as lead, cadmium and zinc includes mixing the solid waste with a buffering agent selected from the group consisting of magnesium oxide, magnesium hydroxide, reactive calcium carbonates and reactive magnesium carbonates, and with an additional agent which is an acid or salt containing an anion that forms substantially nonleachable forms of the metals, which additional agent is selected from the group consisting of triple superphosphate, ammonium phosphate, diammonium phosphate, phosphoric acid, boric acid and metallic iron so that under both acidic and nonacidic leaching conditions the metals in the mixture will be converted to substantially nonleachable forms.

Method for reduction of heavy metal leaching from hazardous waste under

A method of treating solid hazardous waste containing unacceptable levels of leachable metals such as lead and cadmium includes mixing the solid waste with lime and an agent selected from the group consisting of carbon dioxide and bicarbonate. After the solid waste and agent are mixed under conditions which support reaction between the agent and metals, the metals will be converted to nonleachable forms which are relatively stable under normal environmental conditions. If the solid waste material and agent are both dry when mixed, it may be beneficial to add water to facilitate the mixing of the solid waste and agent and the conversion of the metals into nonleachable forms.

Method for treating hazardous wastes

A method of treating solid hazardous waste containing unacceptable levels of leachable metals such as lead and cadmium includes mixing the solid waste with an agent selected from the group consisting of reactive calcium carbonate, reactive magnesium carbonate and reactive calcium magnesium carbonate. After the solid waste and agent are mixed under conditions which support reaction between the agent and metals, the metals will be converted to nonleachable forms which are relatively stable under normal environmental conditions. If the solid waste material and agent are both dry when mixed, it may be beneficial to add water to facilitate the mixing of the solid waste and agent and the conversion of the metals into nonleachable forms.

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Madison, WI, United States of America

Robert R Stanforth