COMPARISON OF THE NEW IRON DOSAGE METHODS FOR DRINKING WATER PRODUCTION

Arsenic is considered as one of the most concerned pollutants in the world due to its adverse health effects. Therefore, its content in drinking water has been recommended to be limited to 10 μg/L (WHO 2006). On of the conventional methods for arsenic removal is based on the addition of ferrous salts that remove it with in a coprecipitation process. Recently, an extra focus has been put on other possibilities to add iron ions during the process, which can be done with help of zero-valent iron (ZVI) or electrolytic iron dissolution. Both techniques has been implemented for removal of heavy metals and arsenic and showed to be useful for this purpose (Kowalski and Søgaard 2012). ZVI is driven by spontaneous redox reactions, which limits its control and therefore optimization. However, in case of iron electrodissolution, where process is driven by the applied current to the sacrifice anode, it can be controlled, which brings main advantage in large scale water processing. However, both techniques have limitations, which results in different area of implementation.
The aim of this work is to compare and evaluate new iron dosage methods by comparing the water treatment plants where ZVI and iron electrodissolution has been implemented for arsenic removal.