One of the worst environmental problems facing humanity in regard to contamination in drinking water is arsenic. The World Health Organisation has set a standard 10 μg/l for arsenic in drinking water. Arsenic is a natural element that is present in many regions of the world. The groundwater can be heavily polluted in these areas, and often no other water sources are available. The case study presented here is situated in northern Serbia. The groundwater shows concentrations up to 135 μg/l with an average of 110 μg/l of arsenic. The additional high concentrations of natural organic matter, phosphates, dissolved methane, volatile organic carbon and ammonia boron and sodium further complicate the treatment.
Different treatment technologies have been tested over the past decades but proved either inefficient or not economical. The pilot testing period started in September 2012 and ended in August 2013. The most stable and economical process was then further optimized and adjusted. The process comprises multiple treatment stages including stripping, precipitation, bio-filtration and two stages ion-exchange as well as partial reverse osmoses.
The process design guaranteed outflow values defined according to the European directive 98/83/EC.