Darby, PA

Time Frame: September 2017 - September 2018

Enviro-Air was contracted to remediate a former MGP site, located on both sides of Darby Creek in Darby, PA. Fifteen thousand (15,000) tons of MGP impacted soil were excavated and disposed of offsite at a treatment/disposal facility. The excavation along the creek involved the following:

- Installation of 6,250 square feet of soldier beams and lagging to allow for the excavation of MGP-impacted soils to a depth of 23 feet below ground surface. In conjunction with the lagging, 40 tiebacks were installed.
- Installation of a well point dewatering system, which ran 24 hours per day, seven days per week.
- Installation and operation of a water treatment plant consisting of activated carbon, bag filters, a weir tank and an 18,000-gallon frac tank.

In addition to the 15,000 tons of MGP-impacted soil that was removed from the site, EAT also excavated a 200 foot stretch of sediment from the bottom of Darby Creek (totaling 4,000 tons). The sediment excavation required the following:

- - Installation of a PortaDam both upstream and downstream of the excavation area. Two 48” x 200’ HDPE pipes were utilized in conjunction with the PortaDam to allow Darby Creek to bypass the excavation area.
  - Installation and operation of localized sumps to minimize water in the excavation area
  - Stabilization of saturated soils with cement kiln dust

A portion of the Darby Creek sediment excavation was around a 48” sewer main, which ran perpendicular to Darby Creek. The sewer main was approximately 60 years old and carries approximately 14 million gallons of sewage per day. EAT injection grouted underneath and on both sides of the sewer main to stabilize the pipe during excavation.

This project also required extensive restoration, including the following:

- - Construction of a boulder wall on top of bedrock by stacking ½ ton boulders.
  - Restoration of the creek bed
  - Installation of Coir matting
  - Installation of live stakes, various trees, shrubs, plugs and specialty grass mixtures

EAT completed the project to the satisfaction of the Client and property owner.

Installation of PortaDam with 48” HDPE pipe for stream bypass

Upstream PortaDam with 48” HDPE pipe for stream bypass

Downstream PortaDam with 48” HDPE pipe for stream bypass

Installation of soldier beams and lagging

Final subgrade of creek banks prior to restoration

Final subgrade of site prior to restoration

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Claremont, NH

Time Frame: June - September 2015

This cleanup was the first of its kind in the state of New Hampshire. The project was a joint effort between the US EPA, New Hampshire DEQ and the Client. The site was located on the Sugar River in Claremont, New Hampshire and was the home of the former Claremont Gas Works, which began manufacturing gas for lighting streets, factories and other buildings in 1859.
Enviro-Air was contracted to perform the following work:

Remove asbestos roofing and dispose of it prior to the demolition of a building
Demolish a large process building
Demolish a gas holder
Perform In-Situ Stabilization (ISS) on 4,000 cubic yards of extremely high DNAPL impacted soil
Excavate, transport and dispose of 9,000 tons of MGP impacted soil
Install a temporary dam and dredge 400 cubic yards of MGP impacted sediment from the Sugar River
Dewater excavations and treat approximately 200,000 gallons of MGP impacted water, which was then discharged to the sewer line
Implement a 1,500 linear foot sewer bypass, replace 900 linear feet of sewer line running through the ISS area and install 3 manholes
Restore the shoreline and wetlands area

This project was completed ahead of schedule to the complete satisfaction of the Client and all regulatory agencies involved.

Excavation of impacted soil to facilitate new sewer line

Temporary dam to allow for dredging of impacted sediment

Impacted soil before In-Situ stabilization

Specialty excavator utilized for In-Situ stabilization

Site overview during In-Situ stabilization

Clean backfill placed over In-Situ stabilized soil

Compacting clean backfill placed over In-Situ stabilized soil

Site overview after In-Situ stabilization

Site overview after backfill and final grading

Site restoration; new chain link fence and live stakes

Site restoration; live stakes and rock to protect river bank

Site restoration; netting placed to minimize damage to plantings by local wildlife

Who You Choose For Clean-up Matters

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Toms River, NJ

Time Frame: January - June 2016

EAT was contracted to excavate and remove both known and unknown substructures and piping, MGP impacted material and TSCA-level PCB impacted material from an area directly adjacent to an active natural gas facility. This project encompassed several different waste streams that required extensive effort to excavate, manage on site, stockpile, transport and dispose of at multiple treatment/disposal facilities. The known/unknown substructures included a tar holder, USTs, concrete pads, timber piles, abandoned natural gas piping and asbestos wrapped piping. Dewatering and handling/disposal of impacted groundwater was a challenging aspect of this project.

Seven (7) waste streams were excavated, segregated and stockpiled on site including:
- TSCA PCB soil
- TSCA PCB pipe/debris
- Low level PCB soil
- Low level PCB debris
- MGP soil
- MGP pipe/debris
- Clean pipe/metal
Excavated, transported and disposed of:
- 2,500 linear feet of underground piping
- 500 tons of TSCA PCB impacted soil, piping and debris
- 5,000 tons of low level PCB impacted soil and debris
- 800 tons of MGP impacted soil
- 180,000 gallons of MGP impacted and PCB impacted water

EAT finished the project ahead of schedule.