Correction to: impact of an in-situ Cr(VI)-contaminated site remediation on the groundwater.

The correct presentation of the 4th sentence in the 2nd paragraph of section Remediation method is shown in this paper.

Impact of an in-situ Cr(VI)-contaminated site remediation on the groundwater.

This study presents the latest results of the groundwater monitoring of a research project, which tested an innovative pump and treat method in combination with an in-situ remediation. This technique was assessed on an abandoned site in Austria, where two hot spots of hexavalent chromium (Cr(VI)) were located. For the in-situ remediation, a strong reducing agent (sodium dithionite) was injected into the underground to reduce Cr(VI) to Cr(III) by using different injection strategies. Throughout this treatment, part of the Cr(VI) is mobilized and not instantly reduced. To prevent a further spreading of the mobilized Cr(VI), the pump and treat method, which uses zero-valent iron to clean the groundwater, was installed downgradient of the hot spots. Based on the groundwater sample analyses, it was possible to distinguish different remediation phases, characterized by excess chromate and excess sulfite. During the excess sulfite conditions, Cr(VI) was successfully removed from the system, but after terminating the sodium dithionite injection, the Cr(VI) rebounded.

Decomposition of dissolved organic contaminants by combining a boron-doped diamond electrode, zero-valent iron and ultraviolet radiation.

This study presents the results of a research project dealing with the degradation of dissolved tetrachloroethene, MTBE and clopyralid by using a boron-doped diamond electrode, zero-valent iron in a fluidized bed reactor and ultraviolet radiation. These treatment methods were tested alone, in any combination of two as well as in combination of all three of them to identify emerging synergy effects. Additionally, the influence of adding H2O2 or H2O2 + H2SO4 is investigated. The experiments revealed that the treatment methods alone were able to decrease the organic contaminant concentrations, yet, the decomposition rate was not very sufficient. Applying the BDD yielded the highest decomposition rates, however, this degradation was accompanied by metabolite production. By combining two methods and adding H2O2, the decomposition was enhanced significantly for any combination. These removal rates were further increased by using the combination of the three treatment methods and adding H2O2 or H2O2 + H2SO4. These high removal rates were not achieved by solely using the combination of the three methods without further addition of chemicals. This research demonstrates the potential, but also the limitations of the investigated system.