An innovative method for arsenic remediation

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The Technology



Title

Environmental SMEs active in remediation technology


Description

 

Contamination of groundwater resources by arsenic is a well-known environmental problem that can have severe human health implications. Arsenic is released from soil environments into groundwater through natural processes and as a consequence of anthropogenic activities.

Typical arsenic removal technologies require a two-step process, oxidation of As(III) to As(V) and removal through a medium. The AsRT technology is the only technology that can remove both species in one step. 

A Greek university has developed innovative technology to reduce arsenic contamination. It uses iron filings (zero-valent iron) and sand to convert inorganic arsenic species to iron co-precipitates, mixed precipitates, and in conjunction with sulphates to arsenopyrites.

The reduction of arsenic is accomplished by passing inorganic arsenic contaminated water through an iron filing/sand (1:1 by weight) "filter", the arsenic removal reactor. An iron removal reactor follows the arsenic removal reactor. The iron removal reactor consists of an aeration unit and a filtration unit. In the aeration unit ferrous iron (Fe(II)) is oxidised to ferric iron (Fe(III)) and ferric hydroxide (Fe(OH)3) is formed. The aeration unit is followed by an iron filtration unit.

The remediation process can be enhanced by passing the arsenic-contaminated water over a sulphate source (barite) or by introducing sulphate ions in the solution. The presence of the sulphate ions provides the opportunity of arsenopyrites precipitation.

The technology can be applied in surface water, groundwater, soils and sediments through different operational systems: (1) In-situ remediation of arsenic-contaminated groundwater using iron-filings-permeable walls, (2) In-situ remediation of arsenic-contaminated sandy soils by incorporating iron filings into the sand, (3) In-situ treatment of contaminated lake and wetland sediments, (4) Treatment of domestic drinking water supply, and (5) Ex-situ treatment of groundwater and drinking water and (6) In-situ treatment of a wastewater discharge containing arsenic.

The technology has been tested successfully in many parts of the world including Maine (U.S.), New Jersey (U.S.), Bangladesh, Chalastra (Central Macedonia, Greece) and Triglia (West Chalkidiki, Greece).

Innovative Aspects:

$1·         It uses recyclable material to remove efficiently arsenic to drinking water standards

$1·         It is the only technology in existence to remove arsenic under anoxic conditions

Main Advantages:

Typical arsenic removal technologies require a two-step process, oxidation of As(III) to As(V) and removal by a medium. The AsRT technology is the only technology that can remove both species in one step. 

The competitive advantages of the AsRT technology are:

$1·         It requires no to minimum maintenance.

$1·         It uses recyclable products (iron filings) as the media for removal.

$1·         The longevity of the filter media is very long (more than a year), requiring infrequent replacement.

It removes arsenic to level below the water quality standards reliably.

 


Markets Addressed

 

Environmental SMEs active in remediation technology

 


Stage of development

Development Phase

Comments: The technology is available for demonstration and has been already field tested.


Intelectual Property status

Copyright

Comments: None