1. miNing Reduction of nitrogen discharges in mining processes and mitigating its environmental impact – mining Frauke Ecke 1, Anders Widerlund 2, Roger Herbert 3 & Sara Hallin 1 1 SLU, 2 LTU, 3 Uppsala universitet

2. miNing Cause of N-problem Ammonium-nitrate based explosives Cyanides in gold extraction processes

3. miNing Deponi 1 Deponi 2 Bioreaktor N Gråbergsdeponier – Lakvattenbildning & N-utsläpp Projektgrupp: Albin Nordström & Roger Herbert

4. miNing Snösmältning (  24 april) lufttemperatur Temperaturgivare i södra deponin

5. miNing Vattenhalt Temperatur

6. miNing Bioreaktor för kväverening 2,1m 44 m Fyllnadsmaterial: träflis med mindre mängd avloppsslam Flöde:  40 m 3 /dygn Tömning träflis Justerbar munk aug 2014

7. miNing Variables that will be optimized in mesocosms to maximize denitrification : Phosphorus concentration Light conditions Presence of organic matter (algae) Temperature Nitrogen removal in mine ponds Tailings and clarification ponds at Kiruna Experimental field site Mesocosms at the experimental field site where nitrogen removal through biogeochemical and microbiological processes in mine ponds will be simulated Project leader: Anders Widerlund

8. Experimental mesocosms General overview of water circulation system and planned simulations “Water tower” Water circulation simulates a water residence time of 15 days in the pond Water inflow Reference Phosphorus addition LightHeat Nitrogen isotope tracer Test MesocosmSimulation / test ReferenceNormal conditions Phosphorus additionIncreased P concentration LightReduced light input HeatAdded heat, warmer climate TestResidence time, other Nitrogen isotope tracerNH 4 /NO 3 uptake in plankton

9. miNing Model developed for nitrogen cycling in mine ponds and mesocosms Redox Layer model Core –15 State variables –Developed using four modules –Highly optimised regarding computation time Graphical user interface

10. miNing Wetlands Nitrogen

11. miNing Denitrification or N-uptake?

12. miNing Main wetland results so far Laboratory = Field Denitrification is main N-removal pathway Differences among species Multiple species cultivation showed highest N-removal potential We need information on total biomass

13. miNing 2015 – whole wetland assessment Biomass

14. miNing Tack! Frågor?

15. miNing

18. Nitrogen problem Kiruna Critical value

19. miNing Nitrogen cycle NO 2 N 2 O N 2 NO 2 N 2 O N 2 NO 3 NH 4 2 OHNO 2 NO - 3 NH 2 OHNO 2 -- + NH 2 OHN2H2N2H2 N 22 NH 4 2 OHNO 2 NH 2 OHNO 2 - +

20. miNing Nitrogen cycle NO 2 - & NO 3 - NO N2N2 N2ON2O NH 4 + Org-N

21. miNing Overall objectives Identification of treatment techniques – remove N from mine site drainage – recipient concentrations are maintained at levels that are in agreement with national and international legislation

22. miNing Treatment systems 1.Studies of N-release from waste rock & bioreactor system for nitrogen removal from mine waters through denitrification 2.System for optimizing microbial denitrification in tailings ponds 3.Wetland systems for nitrogen removal through denitirification, anammox and phytoremediation by macrophytes and algae

23. miNing Waste rock pile & Bioreactor

24. miNing Experimental mesocosms Tailings Water surface Water inflowWater outflow Experimental parameters Phosphorus Heat Light Organic matter Denitrification, anammox Burial of organic nitrogen Instrumentation Temp, pH, O 2, cond Sampling N, P, Chl-a, plankton Nitrogen isotopes Sedimentation (org N) Sediment Laboratory and field measurements have been performed to study the conditions for algal growth and denitrification in the clarification pond Measurements in the mesocosms will start in 2015, with a sampling program based on the results from the laboratory and field measurements

25. miNing

26. Wetland system Natural, constructed & floating wetlands as final treatment step Lab-scale experiments Pilot-scale field studies

27. Denitrification rates Potential denitrification rate (μg N m -2 min -1 ) E. flu

28. miNing

31. Phosphorous

32. miNing N:P