Fate of nano titanium dioxide during combustion of engineered nanomaterial-containing waste in a municipal solid waste incineration plant

Abstract

The market for products containing engineered nanomaterial (ENM) is constantly expanding. At the end of their lifecycle, a significant fraction of the products will be disposed as ENM-containing waste in thermal treatment plants. Up to now there are still uncertainties on the fate and behaviour of ENM during waste incineration. In our investigations, nano titanium dioxide (nTiO2) was selected as an example for ENM, because of its high amount in consumer products and its relevance to the ENM-containing waste stream. Two test series were conducted at the municipal solid waste incineration plant “Gemeinschaftskraftwerk Schweinfurt”. For each test series, background concentrations of titanium were measured first. Samples of bottom ash, bottom ash extractor water, fly ash (boiler ash, cyclone ash), flue gas cleaning products (spray absorber ash, fabric filter ash) and washing water from the wet scrubber were taken in order to determine the fate of nTiO2. The flue gas was sampled at three points: after boiler, after cyclone and before stack. The experiments showed that most of the used reference material was located in the solid residues (i.e. bottom ash) while a smaller part was detected in the products of the flue gas cleaning. In the purified flue gas before the stack, the concentration was negligible. The flue gas cleaning system at the Gemeinschaftskraftwerk Schweinfurt complies with the requirements of the best available techniques and the results cannot be transferred to plants with lower standards.

Release of gold (Au), silver (Ag) and cerium dioxide (CeO2) nanoparticles from sewage sludge incineration ash

“…The selective accumulation of ENPs in bottom ash has been previously observed for TiO 2 -NPs. 13,24 The excellent recovery of Au in the fly and bottom ash and the agreement between the calculated and ideal EFs indicated that during the incineration experiment, all relevant Au mass flows were collected, i.e. Au volatilization was insignificant.…”

“…In the first fraction, the Ca concentration and pH were in equilibrium with Ca(OH) 2 (SI = 0.03), but the SI already dropped to −0.75 in the second fraction and continuously decreased. The elevated Ca concentrations (7000 and 12 000 mg kg −1 Ca in sludge and fly ash, respectively) can be traced back to the hard water (French degree hardness (fH) = [22][23][24][25] in the catchment of the WWTP in La Chaux-de-Fonds originating from the limestone rich lithology of the Jurassic mountain range in the western part of Switzerland. As observed in experiment A, the release of particulate Au was independent of the Ca concentration.…”

Leaching of Titanium Dioxide Nanomaterials from Agricultural Soil Amended with Sewage Sludge Incineration Ash: Comparison of a Pilot Scale Simulation with Standard Laboratory Column Elution Experiments

“…As a basis for the formulation of Hombikat UV 100 WP, nTiO 2 , in the form of the product Hombikat UV 100 with a primary particles size of <10 nm, was employed. Further information can be found in Börner et al [ 16 ] and Oischinger et al [ 17 ]. The application of Hombikat UV 100 WP lies mainly in the photocatalytic area, as the nTiO 2 is present in the anatase modification.…”

Spray scrubber for nanoparticle removal from incineration fumes from the incineration of waste containing nanomaterials: Theoretical and experimental investigations

“…Most of these studies occurred at laboratory-scale (Cernuschi et al 2019;Ounoughene et al 2015Ounoughene et al , 2019Pourchez et al 2018;Baumann et al 2017;Buonanno and Morawska 2015;Massari et al 2014;Buha et al 2014;Marr 2013, Vejerano et al 2014;Derrough et al 2013;Cernuschi et al 2012;Mueller et al 2012;Buonanno, Ficco, and Stabile 2009), making some of their conclusions somewhat study specific as the full complexity involved in waste incineration was not taken into account. For the large-scale studies (Oischinger et al 2019; Baran and Quicker 2017;B€ orner et al 2016;Lang et al 2015;Walser et al 2012), the majority of the NMs ended up in the bottom ash while some fractions of the NMs were detected in the fly ash. These conclusions were also partly supported by some of the lab-scale studies.…”