Nitrate consumption by the oxidation of sulfides during an enhanced natural attenuation project at a contaminated site in Berlin, Germany

Abstract Background Organic pollutants at contaminated sites are often eliminated naturally by biological degradation. The redox processes responsible can be enhanced infiltrating electron acceptors such as nitrate or sulfate into the aquifer. However, addition of oxidative agents lead to undesired side-effects in saturated soil zone consumption oxidation sulfides contained Laboratory-scale 1D column experiments up flow mode were performed evaluate potential and related kinetics during an natural attenuation project a site with monoaromatic compounds trimethylbenzene. Water containing was infiltrated aquifer material sulfides. To study side reactions, conducted low levels organic hazardous compounds. Results results indicate that sulfide oxidized simultaneous formation nitrate-consuming processes. degradation rate calculated 1.26 mg kg −1 per exchanged pore volume, corresponding 8.5 case incomplete denitrification 3.4 complete denitrification. Conclusion presence leads reaction following linear function sufficient availability nitrate. This information is helpful for planning ENA projects reduce risk under- overdosing acceptor nitrate, which may lack needed enhance biodegradation contaminants deterioration groundwater quality.