Arsenic in groundwater: Overview and evaluation of removal methods

IGRAC's global inventory of arsenic occurrence in groundwater described on this site revealed that groundwater resources in many regions are, or might be, contaminated with this hazardous compound. The maps showing the probable distribution of arsenic provide valuable information for various water users However, pinpointing the location and assessing the risk do not solve the contamination problems. In many areas, contaminated groundwater is the only water resource available. Local population in such areas has no choice but using this water. It is very important that once the occurrence of contaminated water is assessed, suitable removal techniques are determined and applied as soon as possible.

Most removal techniques are complex and/or expensive. Moreover, they often require a certain level of technical skills. There are many overviews of arsenic removal technologies already available. This IGRAC's overview summaries information on removal methods and evaluates these methods in terms of efficiency, costs and required technology. In this way we aim to provide low threshold guidelines, easily understandable to "problem owners" seeking a practical solution for improvement of their groundwater resources. Suitability of various removal methods related to scale of application, costs and removal efficiency can be summarized as follows:

The colours in the matrix correspond with the appropriateness of the method for the given situation:

• Green colour means that the method is very suitable
• Orange colour means average suitability
• Red colour means that the method is unattractive or not applicable for the given situation.

IGRAC report SP 2007-2 outlines basic principles of common methods as well as of some new technologies for arsenic removal. To help water users by choosing the most appropriate methods for their situation, process selection decision trees for both large scale applications and small scale systems are presented. You can download the complete report (pdf, 0.7MB).