Title: Selenium removal from wastewater using dissimilatory metal reduction

Primary Researcher: Markus Lenz
Email address: Markus.Lenz@wur.nl
Submitted on: July 19, 2004

Start date: 01 July 2004
End date: 01 June 2008

Introduction:

The outstanding importance of selenium in environmental research is caused by the fact, that it shows only a marginal line between nutritious optimum (as an essential element) and toxic exposure. Selenium occurs in different valence states and different phases in the environment. The toxicity of selenium compounds varies greatly in dependence of the valence states.
During the process of dissimilatory metal reduction, soluble oxy-anions of metals serve as electron acceptors for electrons originating from the degradation of organic compounds, from H2 or from elemental sulfur. With the reduction of the metal, anaerobic bacteria conserve energy, which allows growth under unfavorable conditions.
Accourding to this, water-soluble selenite (+IV) or selenate (+VI), which are the most frequently encountered forms in aerobic waters, can be biologically reduced to insoluble, elemental selenium.

Aim:

The research aims at the establishment of a biological treatment system for selenium decontamination from wastewaters.

Research:

Not only on the mere optimization of removal rates, but also on the separability of the precipitate, the occurring pathways of the conversion, the influence on the composition of the microbial community and the toxicity of the effluent will be investigated.

Future Research

Application of the reduction processes to other oxy-anions (Chromium, Uranium, Molybdate, Technetium…). Upscaling to field-scale reactors.

External funding

Yes

External Funding Sponsors

Marie Curie Excellence Grant (MEXT-CT-003-509567)