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North American Lake Management Society 2008 Lake Louise Symposium November 2008

North American Lake Management Society 2008 Lake Louise Symposium November 2008. REHABILITATION OF A PHOSPHORUS IMPACTED LAKE WITH FERRIC CHLORIDE GATINEAU VALLEY QUEBEC. Lake Heney Rehabilitation TOPICS. Description and background Proposed solution Implementation Site restoration.

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North American Lake Management Society 2008 Lake Louise Symposium November 2008

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  1. North American Lake Management Society2008 Lake Louise SymposiumNovember 2008 • REHABILITATION OF A PHOSPHORUS IMPACTED • LAKE WITH FERRIC CHLORIDE • GATINEAU VALLEY • QUEBEC

  2. Lake Heney RehabilitationTOPICS • Description and background • Proposed solution • Implementation • Site restoration

  3. Lake Heney • 150 km north of Ottawa • Surface area 12 km2 • Utilisation: fishing, hunting and recreation • Other use: fish farm (94-99)

  4. Sources of phosphorus Load (kg/an) Information provided by the Lake Heney Foundation

  5. Phosphorus ConcentrationsPredicted and Actual Information provided by the Lake Heney Foundation

  6. Lake Heney Specifics • Long residence time: 7 years (typical is 0.5 yr) • phosphorus accumulation • Large lake without public access

  7. How to Correct the Situation? • Inject ferric chloride (FeCl3) • reactive Fe enables the precipitation of P • reactive Fe slows down the release of P from the sediments

  8. Specifics of the Intervention 2000 tonnes of FeCl3 to be injected: • 55 truckloads in 20 days • Fall turnover • best mixing • predominance of reactive PO4 • Corrosive material • avoid metals • Maximum dilution

  9. FIRST STEP: Regulations and Authorisations • Ministry of Environnement • FeCl3 • construction work on the shore • Maritime regulations • Transportation • hazardous materials • oversized equipment • Health and safety

  10. Find the best FeCl3 supplier

  11. Kemira Water Canada Inc.

  12. Delivery by rail and truck

  13. Design of the injection system

  14. Conceptual Design CONCEPTUAL SKETCH

  15. Construction of the staging area

  16. BARGE ASSEMBLY

  17. RECIRCULATION PUMP (4000 L/min)

  18. VENTURI INJECTION SYSTEM FeCl3 (75 L/min) Water pumped from the lake (2000 L/min)

  19. Diffuser Ports

  20. IN OPERATION

  21. Daily delivery of ferric chloride (3 trucks/day)

  22. End of the project: The ice came in!!!

  23. 18 consecutive days of spreading • 46 tanker trucks unloaded • The objective of 1.3 mg/L Fe was met • Monitoring to start in Spring 2008

  24. Site Restoration CONSTRUCTION OF THE BARGE

  25. Conclusions It is possible to treat large lakes: • In a short time period • While minimizing the short term effects of FeCl3

  26. Quote from a lake resident • « We have turned back the lake’s biological clock by 25 years »

  27. QUESTIONS

  28. 2008 Results from the Lake Association’s Web Site March 6: 8-9 μg/L for Total Phosphorous April 27: 10 μg/L for Total Phosphorous Sept.: 11 μg/L for Total Phosphorous

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