Current Trends and Case Studies in Contaminated Sediment Capping

Transcription

1 Current Trends and Case Studies in Contaminated Sediment Capping Archie Filshill, Ph.D. Theresa Andrejack Loux, Ph.D. Golder Associates Bristol, PA

2 Sediment Removal Dublin, Ireland Royal Canal Job bid as sediment removal via wet excavation Value engineering solution: pumping and dewatering of sediments in geotubes February 4,

3 In-Situ Capping Passive Capping Isolation Layer Relatively thick layer of clean sand Separation Layer Sand Geotextiles Active Capping Active Layer Adsorptive Media Relatively thin layer Bulk Placement Prefabricated layer Ballast system Sand/Gravel/Rip Rap Gabions Marine Mattress Articulating Concrete Blocks Ballast System Sand/Gravel/Rip Rap Gabions Marine Mattress Articulating Concrete Blocks February 4,

4 Passive Capping February 4,

5 Marine Mattress Passive Capping - Marine Mattress Typical Size: 5 ft Wide x 1 ft Thick x Varied Lengths 35 ft max HDPE, min. 2% carbon black Compliments of Tensar Compliments of Tensar

6 Passive Capping Project Staten Island, NY Tidal stream Geotextile/Geogrid 2 ft Sand overlay February 4,

7 Passive Capping Projects Westville, NJ Pittsfield, MA Hand-placed ACBs Underlying Geotextile February 4,

8 Active Capping Materials February 4,

9 Types of Active Media Organoclay NAPL, PAHs, PCBs, Methyl Mercury Organoclay MRM NAPL, PAHs, PCBs, Hg, As Apatite Heavy Metals Granulated Activated Carbon PAHs, PCBs, BTEX February 4,

10 Bulk Placement Bulk Placement Compliments of CETCO Compliments of CETCO February 4,

11 Active Capping February 4,

12 Prefabricated Geosynthetic Mats Variety of media used in prefabricated geotextile mats Organoclay, Organoclay MRM, Apatite, GAC Sand Combinations of the above ¼ Inch Compliments of CETCO

13 Prefabricated Geosynthetic Mats Compliments of CETCO February 4,

14 Benefits of Prefabricated Geosynthetic Mat Provide thin layer of adsorptive media to immobilize contaminants Reduce overall cap thickness Decrease incidence of contaminants in surface water Manufactured material provides consistent distribution of active media throughout mat Easy to verify limits of capped sediments Thick Sand Cap Thin Sand Cap Prefabricated Mat Contaminated Sediment Geotextile Contaminated Sediment

15 Bergen Harbor, Norway February 4,

16 Bergen Harbor, Norway Contamination from 1920 s Mostly Hydrocarbons Permanent trial 50,000 sq. ft. 100 mm sand surcharge All seams monitored by video February 4,

17 Bergen Harbor, Norway February 4,

18 Bergen Harbor, Norway February 4,

19 Groton, Connecticut February 4,

20 Shoreline Installation February 4,

21 Shoreline Installation February 4,

22 Shoreline Installation February 4,

23 Completed Project Compliments of B. Marcek, Maxymillian Technologies February 4,

24 Augusta, ME February 4,

25 Active Capping with Hard Armor February 4,

26 Active Capping with Hard Armor Anchor Trench at Toe Soil Anchors throughout Anchors sealed February 4,

27 Soil Anchors February 4,

28 Active Capping with Hard Armor February 4,

29 Completed Project February 4,

30 Utica Harbor, Utica, NY February 4,

31 Utica Harbor, NY February 4,

32 Utica Harbor, NY February 4,

33 Utica Harbor Former MGP site Harbor - 14 acres 15 deep water 440 panels of RCM 2 side overlap per panel 4 end overlap Divers to confirm overlap Google Earth February 4,

34 Deployment from Barge Prefabricate Panels 23 panels 100 x 600 Eliminate Divers Reduce material overlaps Saved > 70,000 sq.ft. February 4,

35 Panel Assembly February 4,

36 Soil Anchors and Ballast February 4,

37 GPS stations on barge February 4,

38 As-Built February 4,

39 Conclusions In situ caps are good alternatives where sediment removal costs are prohibitive Multiple options exist for material selection in passive and active sediment cap design Prefabricated mats allow for uniform layer and easier QA/QC during construction Varied installation methods based on sitespecific conditions Careful consideration of means and methods for construction can provide cost savings

40 THANK YOU February 4,