Groundwater treatment with the use of zero-valent iron in the permeable reactive barrier technology

Abstract

The industrial dumping sites located in the southern provinces of Poland pollute groundwaters with metals. In the article, the possibility of groundwater (polluted by metals) treatment with the use of Permeable Reactive Barrier Technology has been presented. In this technology, the contaminants are removed from the aquifer by a flow of the groundwater through a PRB filled with a special reactive material. The wastewater (which simulated groundwater) circulated through the column filled with zero-valent iron in the laboratory tests. During the tests, the treatment processes proceeded. Chromium, copper, nick-el, cobalt, lead, cadmium and zinc, occurring in the water as cations and anions, have been removed in the iron bed. The rapid metal removal has likely occurred due to the reduction and precipitation/co-precipitation and/or due to adsorption onto the iron metal surface or/and onto the iron corrosion products. Barium Ba2+ was the only metal, which has not been removed from the wastewater in the column. A rapid decrease of the redox potential and oxygen concentration as well as an increases of the pH value and stabilizations have also been observed during the flow of water through the column. Due to the Fe/Fe2+ half reaction during the treatment processes, the iron concentration has increased as well