Melville Water Tower Soil Excavation Completion

Transcription

1 Melville Water Tower Soil Excavation Completion

2 MELVILLE WATER TOWER - Introduction Tower consisted of a 50,000-gallon elevated tank on a steel tower. Tower was constructed in 1930s to provide fire protection to the fueling facilities at Melville Marina Area. Previously surrounded by a locked chain-linked fence. Located adjacent to the Melville Elementary School. Lead found in soil as a result of paint on the tower applied and removed between the 1940s and the 1990s. Photo May 2006

3 MELVILLE WATER TOWER Discovery Timeline Paint Chips found on the ground in early September A secondary fence was erected September Navy picked up chips twice daily late September 2005 through June Navy, the school, and Rhode Island Department of Health met with parents 10/6/05. Navy provided transportation to students from the development to the south. Rhode Island DEM conducted initial soil screening tests December 2005.

4 DISCOVERY Concentration of Lead >150 mg/kg (RDEC) Concentration of Lead > 500 mg/kg (ICDEC) Concentration of Lead >1000 mg/kg Route 114 Results reported by RIDEM, March 2006 screening results Surface Soil, 0-3 inches

5 SOIL INVESTIGATION

6 PROJECT STARTUP Contract specifications Contractor selection Design the action plan Locate disposal facilities Address local utilities Traffic plan Public meeting Set the schedule

7 EXCAVATION PLAN

8 SOIL REMOVAL OVERVIEW Removal Included: Removal of some of the trees at the south side. Removal of soil up to 2 or more feet below ground surface under the tower area. Confirmation sampling and re-excavation of some areas. Removal of the old concrete footings, confirmation samples collected again. Removal of surface soil across most of the rest of the site. Backfill with clean soil and re-seed.

9 CRITERIA FOR LEAD IN SOIL Criteria applicable to lead in soil RIDEM Exposure Criteria for residential soil: 150 mg/kg Note: lead based paint contains >50,000 mg/kg

10 EXCAVATION Removed: two feet of soil in Area A ; six inches of soil from Area B ; one additional foot of soil from area C (a subset of area A); and additional soil as needed from around the footings and foundations. Confirmation samples collected. Additional excavation performed in some areas to achieve goals.

11 CONTAMINANT CONTROL Soils maintained wet to assure dust would not travel. No stockpiles of soil were allowed on site. Dust monitoring was conducted daily. All monitor results showed no transfer of contaminants.

12 DECONTAMINTATION Trucks moving in and out stayed on clean areas for loading. Paved area only used to access site. All trucks leaving site were decontaminated prior to departure onto paved areas.

13 CONFIRMATION SAMPLING Confirmation samples taken 10 feet apart. Total 417 samples. All samples analyzed by laboratory certified in the State of Rhode Island. Areas where results showed lead > 150 mg/kg were reexcavated. Samples split for quality assurance. Samples also analyzed for other metals.

14 FOUNDATIONS AND FOOTINGS Concrete footings demolished after soil removal goals were met. Concrete removed and disposed of as construction waste. Existing water line removed to the edge of property and capped.

15 OVERSIGHT AND QC Tetra Tech provided oversight of the excavation contractor. Navy provided oversight of both Tetra Tech and their subcontractors. Split samples with different labs to assure compliance. RIDEM inspected site and conducted limited photodocumentation.

16 DISPOSAL Hazardous soil taken to EQ Detroit, Michigan. Transportation via truck to Providence, transferred to rail cars. Total hazardous soil = 614 Tons (approximately 400 cubic yards).

17 DISPOSAL (continued) Non- hazardous soils taken to tank farm 5 and staged in a specific holding area: Soils characterized for disposal. Used for daily cover at Crapo Landfill New Bedford MA. Total of 929 tons of nonhazardous soil (approximately 620 cubic yards). Concrete disposed of at BFI Fall River Massachusetts.

18 BACK-FILL AND COMPLETION 1,435 Tons of sand/gravel mix brought to the site, leveled and compacted. Topsoil placed six inches thick across the site. Material sampled prior to bringing to site. Material originated at JAM Materials Middletown

19 QUESTIONS

20 THANK YOU