ferroDECONT process

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The ferroDECONT process is a solid-liquid fluidized bed process for the treatment of water contaminated with heavy metals . The process is used by the university offshoot ferroDECONT GmbH. In this case come fluidized bed reactors are used, with zero-valent iron - granules are filled and the bulk type group D by Geldart belong.

history

In-situ and ex-situ wastewater treatment plants using elemental iron are known. The main problem with these systems is the necessary residence time in the range of hours for the contaminated wastewater in the reaction zone. This is caused by the passivation of the reactive surface of the iron bed. A regeneration of the filling material - which would increase the reaction kinetics - is only possible by replacing the bed. As the amount of water to be treated increases, the expenditure on equipment increases enormously.

The ferroDECONT process was developed by Peter Müller, Robert Mischitz and Christian Weiß at the Montan University Leoben 2010–2011 in the course of a research project on the “In-situ restoration of chrome damage through reduction processes ” . For the first time, the chemicals required for conventional " Pump & Treat " processes for treating groundwater in contaminated site remediation projects were replaced by zero-valent iron. The further development of the process also enables the destruction of organic pollutants in contaminated water.

In the course of the process development in the RECOMET and RECOMET 2.0 projects, it turned out that this method can also be used to efficiently clean up water containing heavy metals in addition to the remediation area .

In 2010 the process and the corresponding system concept were registered with the EPO for a patent. The corresponding issue took place in 2015.

Since 2019, the process has been used to clean up the contaminated site K22 ("Lederfabrik Neuner") to treat the groundwater.

Chemical-physical basics

The chemistry of the redox process between zero-valent iron and numerous pollutants (e.g. heavy metals) is already used in conventional protection and remediation of contaminated sites. A prominent example of this are “ reactive walls ”. Problems with these fixed bed fills arise from precipitation, the passivation of the iron surface and gas logging effects in the bed. This reduction in efficiency is prevented by the flow regime of the ferroDECONT process.

The zero-valent iron acts as an electron donor and reduces higher-quality pollutant compounds. The aim is to reduce the toxicity of the compounds or to convert them into non-toxic compounds.

An example is the reduction of toxic chromate to the toxicologically insignificant trivalent chromium hydroxide :

application

Additional salt build-up in the water as a result of the treatment is largely avoided, which means that this cleaning method is well suited for recycling.

Areas of application arise in the securing and remediation of contaminated sites as well as in the treatment of industrial and process water contaminated with heavy metals. In the contaminated site remediation area, the treated groundwater can be returned to the two environmental compartments of water and soil. Industrial water can be treated to close the process water cycle.

Alternative procedures

  • conventional “Pump & Treat” procedures
  • reactive walls with zero-valent iron material

literature

  • H. Burmeier et al .: Use of cleaning walls with air flow to clean up contaminated sites. University of Lüneburg, Faculty III, Environment and Technology, 2006 (BMBF project number: 0271241, PDF )
  • AB Cundy, L. Hopkinson, RLD Whitby: Use of iron-based technologies in contaminated land and groundwater: A review. In: Science of the Total Environment . 400, 2008, pp. 42-51, doi : 10.1016 / j.scitotenv.2008.07.002 . 18692221.
  • Environmental Protection Agency: In Situ Treatment of Soil and Groundwater Contaminated with Chromium. Technical Resource Guide, EPA / 625 / R-00/005. Office of Research and Development, US Environmental Protection Agency, Cincinnati, Ohio, USA, 2000 ( PDF ).
  • A. Parbs, M. Ebert, A. Dahmke: Influence of mineral precipitation on the functionality and long-term effectiveness of Fe 0 reaction walls - a review based on 19 Fe 0 reaction wall locations. In: Groundwater Journal of the Hydrogeology Section. 12, 2007, pp. 267-281, DOI: 10.1007 / s00767-007-0043-8 .
  • D. Höllen, Daniel; KP Sedlazeck; P. Muller; R. Mischitz; R. Pomberger: The ferroDECONT process for remediation of contaminated sites and recycling-oriented wastewater treatment. / in: Austrian water and waste management: ÖWAW; Journal for all scientific, technical, legal and economic questions of the entire water and waste industry , Volume 66, 2014, pp. 408–416.

Web links

Individual evidence

  1. ↑ patent application WO2007143350 : Systems and Methods for Treating Water with Iron. Filed May 31, 2006 , applicant: Alcoa Inc., inventors: Dennis Fulmer, Rajat S. Ghosh, Kevin Kitzman, John Smith. ‌
  2. ↑ Peter Müller: Field trial of an innovative in-situ remediation process for chromate . In: KE Lorber, et al. (Ed.): Waste management, waste technology, landfill technology and contaminated sites (=  conference proceedings for the 11th Depo-Tech conference ). Leoben 2012.
  3. ↑ P. Müller, KE Lorber: Implementation of Fluidized Granulated Iron Reactors in a Chromate Remediation Process . In: 12th International UFZ-Deltares Conference on Groundwater-Soil-Systems and Water Resource Management (=  AquaConSoil ). Barcelona 2013.
  4. ↑ Patent application WO2012059480 : INSTALLATION AND PROCESS FOR REMOVING CONTAMINANTS FROM AQUATIC FLUIDS. Registered on October 31, 2011 , published on May 10, 2012 , applicant: Montanuniversität Leoben, inventors: Peter Müller, Robert Mischitz, Christian Weiß. ‌
  5. ↑ Altlast K22: Lederfabrik Neuner , altlasten.gv.at, accessed on June 22, 2020.
  6. ↑ PORR Austria: Remediation of contaminated sites at the Neuner leather factory in Klagenfurt , YouTube.com, uploaded on October 9, 2019, accessed on June 22, 2020.