Förbättrad behandlingsmetod

för slaggrus

Improved treatment of bottom ash –

pilot scale test

Lale Andreas

LTU, AvfallsteknikTest areas at Boden Energi

power plant

Motivation for the choice of treatment

• Simple, cheap

• Accelerated aging

• Carbonation to reduce pH and leaching of trace elements

• Zero valent iron (Fe0)

• Used in soil remediation to stabilize heavy metals

• Trace elements bind to Fe-oxides

• Increases the number of sorption sites

• By-product from the steel industry

Background

• 800 000 t/a bottom ash from waste incineration

• Used as landfill cover material or are landfilled

• Potential as secondary construction material – IF we can control the hazards

• Study: Effect of carbonation and Fe amendment on MSWI BA leachingcarbonation and Fe amendment

• Design of test areas

• Application for permit (to Boden municipality / Norrbottens county administration)

• Characterisation of ashes – twice! 2016/17 and 2018

• Construction of test areas

• Sampling of infiltrated water four times and emptying of wells and lysimeters

• Online monitoring of temperature and precipitation

Activities in the project

Test areas at Boden energi power plant (BEAB)

Provyta 1

Åldrat slaggrus + Fe0

Referensyta 2

Makadam

Provyta 3

Åldrat slaggrus

14 m

12 m12 m 12 m

3 st. brunnar ø 1 m med tät botten; nivåmätare och dränkbar pump; el 230 V, värme

Mätbodel 230 V,

värme

Aged

bottom ash

Crushed

rock

Aged

bottom ash

with Fe0

Test areas at Boden energi power plant (BEAB)

August 2018 September 2018

October 2018

October 2019August 2019

Results and lessons learned

• Delay of necessary permits can devastate time planning and lead to loss of results and

money.

• Used ashes differ a lot from earlier characterised ashes (total composition and leaching

behaviour) → less applicable results.

• Stabilising effect of Fe0 on the mobility of contaminants – confirmed in lab test but opposite

trend in the field.

• Reference material leaches less regarding most elements but more Co, Cu, Mn, Mo and Ni.

• The ash has an insulating effect, especially the bottom ash without Fe0

Next steps

• Final evaluation and reporting/publishing

• Conclusions towards possible uses alternative landfilling of the

bottom ashes (TLR 7)

• Discussions with BEAB about continued monitoring

Ash sorting and metal recycling