LANCE: Laccase-nanoparticle conjugates for the elimination of micropollutants (endocrine disrupting chemicals) from wastewater in bioreactors

Abstract

Elimination of recalcitrant chemicals during wastewater treatment is a difficult problem for both developing and industrialized countries. The biological elimination of very persistent xenobiotics such as endocrine disrupting chemicals from municipal and industrial sewage treatment plants is an ambitious challenge as existing physico-chemical methods, such as advanced oxidation processes, are energy-intensive and consume high amounts of chemicals. Through the entry into force of strict legislative measures, such as the Water Framework Directives (EU WFD in Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for the Community action in the field of water policy, 2000) and REACH (REACH EU in European Community Regulation on chemicals and their safe use (EC 1907/2006), 2007), the market for wastewater treatment is exploding. For instance the European market potential for the membrane bioreactor technology is estimated to 57 M€ per year. Based on recent progresses in nanotechnology, new developments in catalysis and environmental applications can be foreseen for the near future. Indeed, because of high surface area-to-volume ratio in nano-systems, heterogeneous enzymatic or catalytic reactions can be greatly enhanced. In the LANCE project a nanoparticle (NP)-based technology is under development. Cheap and resistant oxidative enzymes, i.e. laccases are immobilized onto the surface of the particles in order to produce systems possessing a broad substrate spectrum for the degradation of cocktails of recalcitrant pollutants. One of the objectives is to produce NPs that are compatible with wastewater treatment and can be synthesised in a cost-effective and large-scale fashion, e.g. silica-based NPs using flame spray pyrolysis and emulsion-based techniques. The modified particles are applied in bioreactors where they are retained, i.e. membrane bioreactors or perfusion basket reactors to eliminate pollutants from the wastewater. Such reactors allow multi-cycle use of the NPs coated with active enzymes and thus contribute to decrease the treatment costs. The two-year activities of the LANCE project encompass the synthesis of various NP systems, the immobilization of selected low cost industrial laccases on the latter, and the technical and scientific proof of the “depollution” concept.