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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Blue Island, IL

Time Frame: October 2009 - April 2010

EAT was contracted to perform the excavation of a six acre former MGP plant located in Blue Island, IL. The project involved the excavation, transportation and disposal of over 110,000 tons of MGP impacted soil. The entire 6-acre site was divided into 25′ X 25′ grids. Each grid was excavated and post excavation samples were taken. Oversight was by the Illinois EPA. Excavation depths ranged from a minimum of 3′ to up to 12′. EAT removed a tar separator and stabilized the contents of the separator, which was then shipped to a hazardous waste landfill. In addition, over 1,000 linear feet of 24″ iron piping was cleaned, removed and recycled. Three gasholders were removed as well as one 225,000-gallon AST. Multiple other vessels as well as hundreds of feet of smaller piping were cleaned and removed. Over 100,000 gallons of impacted water was collected and shipped offsite.

EAT rerouted a stream and remediated the streambed, excavating to depths up to 8′ in the bed. Over 25,000 tons of backfill were imported and compacted.

Over 6,000 truckloads of material were shipped out of and brought into the site, along a railroad siding over the course of 7 months.

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Sea Isle City, NJ

Time Frame: September 2013 - May 2014

EAT was contracted to excavate, transport, and dispose of 16,000 tons of MGP impacted soil from 3 residential properties located on the barrier island of Sea Isle City, NJ. The project involved the following:

Demolition of 3 residential properties
Driving 33,250 square feet of steel sheet piling to create (16) individual excavation cells
Excavation dewatering
Onsite water treatment and discharge
Construction of a 118′ X 164′ temporary enclosure, which utilized two air scrubbers
Stabilization of saturated MGP-impacted soil
Site Restoration

EAT completed the project on time and with no safety incidents.

Excavation of impacted soil from one of 16 cells created with sheet piling

Mini excavator was lowered into a cell to ensure all impacted soil was removed

Triaxle dumped clean sandy backfill into a finished excavation cell

Temporary enclosure was moved to enclose additional excavation areas

Triaxle trucks loaded with impacted soil

Clean sandy backfill placed by skid steer

Trench roller was utilized to compact clean sandy backfill in lifts

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Mount Joy, PA

Time Frame: April - September 2015

EAT was contracted to demolish a residential home and gas regulator station to facilitate the removal of a tar separator as well as other subsurface MGP structures. As the site was located in a residential area, it was necessary for Enviro-Air to construct a temporary building over the top of the subsurface MGP structures and excavate the MGP-impacted soil inside the enclosure. The temporary enclosure was equipped with a carbon absorber and air scrubbing system. The atmosphere inside the building was maintained under negative pressure to contain and scrub the vapors. EAT excavated and disposed of over 4,000 tons of MGP impacted soil. During the project, Enviro-Air was responsible for dewatering. This was a very difficult project in that access was limited and a residential home was adjacent to the site. EAT completed the project with no incidents. In 2017, Environmental-Air returned to the remediated site to construct a park, later named Old Standby Park. EAT worked closely with the Borough of Mount Joy to create the park in accordance with their requests. The park construction included the following:

Installation of a one way road and parking spaces per PENNDOT standards
Installation of a concrete walkway through the park
Installation of benches and lighting
Planting a variety of trees, shrubs, and flowers
Placing a monument in the park
Maintenance of the park until the Borough of Mount Joy took ownership

EAT completed the construction of Old Standby Park ahead of schedule, to the satisfaction of the Borough of Mount Joy

“Old Standby” manufactured gas plant, constructed in 1879

Excavating inside enclosure; odor suppressant foam has been sprayed on excavated soil to minimize odors/vapors

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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

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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.