A cheaper and greener method for groundwater remediation

Alumichem participates in a new research project (GreenCat) that will develop a greener and cheaper technique for removing so-called chlorinated solvents from contaminated soil and groundwater. Bones, which char at high temperature, and “green rust” are the main ingredients of the new environmentally friendly cleaning method.
Alumichem’s role is to produce “Green Rust”. Green Rust is a layered iron oxide that selectively reacts with chlorinated solvents and thereby breaks them down.

Alumichem is working with a consortium to develop a method for the purification of polluting grounds. The consortium consists of the Department of Environmental Chemistry (University of Copenhagen), Region Hovestaden, GEUS (Ministry of Climate, Energy and Supply), Amphos21 and GEO. The project aims to develop an environmentally friendly, cheap, and effective method for cleaning up land and groundwater contaminated with chlorinated solvents.

A cheaper and greener method for groundwater remediation  

The purification method is unique because it is expected to work as quickly as the best existing methods, but at a much lower cost and using non-toxic and naturally occurring ingredients. Thus, it will outcompete less sustainable and more expensive methods. Society will be able to use previously contaminated land for construction and other activities more quickly, pollution of drinking water will be reduced, and negative effects on human health and ecosystems will be limited. In addition, the material is expected to have a longer-lasting effect than the existing products because it reacts specifically with chlorinated solvents.

Chlorinated solvents have previously been used in many different industries for, for example, degreasing and cleaning clothes. Even small spills on the several thousand sites where the solvents have been used are today a serious threat to drinking water reservoirs and human health.

Alumichem to produce sustainable “Green rust”  

In the project, Alumichem’s role is to produce “Green Rust”. Green Rust is a layered iron oxide that selectively reacts with chlorinated solvents and thereby breaks them down. The green rust is mixed with coal and pumped into the ground where it reacts with the chlorinated solvents and breaks down into harmless salts and gases.

It is costly and difficult to clean up grounds contaminated with chlorinated solvents. The existing methods for removing chlorinated solvents on contaminated land are expensive and not always effective. Some require repeated treatments, and toxic and carcinogenic by-products can form. Often requires treatment of large amounts of soil or removal to landfill.

Green rust is harmless, it is a natural material that forms in nature as an intermediate phase when metallic iron oxidizes. It occurs naturally in meteors and in few igneous iron deposits. When it oxidizes, it forms Fe3+ oxide, which is harmless.

Technically, the new method works by virtue of a process called “reductive dechlorination”, which cleaves chlorine atoms from the chlorinated solvents. This happens when electrons are “pumped” from the green rust to the chlorinated solvents via the coal. The result is non-toxic chloride in the water and harmless carbon compounds.

Learn more about the Greencat project below


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