Posted on November 5, 2024
A Targeted Brownfields Assessment lead to remedial actions to restore and redevelop a contaminated property in the heart of Downtown Bennington, VT.
The Putnam Block originally consisted of six (6) parcels totaling approximately 4.3 acres in the heart of downtown Bennington bounded by Main Street, and South Street. The eastern portion of the Site is part of the Bennington historic district. Former site uses include office buildings, auto repair, battery service / storage, newspaper printing, paint storage, carpet cleaning, hardware store with lumber yard, hotel, black smith, and general storage. Re-Development of the eastern portion of the property was completed in 2021. Demolition of the lumber yard structures, removal of impacted soil and re-development with new residential and mixed use facilities will commence in 2022.
Several phases of Brownfields planning and assessment have been completed for the Site since 2014. Under contract to EPA, Region 1, Nobis completed a Targeted Brownfield Assessment (TBA) for the Site in 2017 on behalf of the Bennington County Redevelopment Corporation (BCRC). The TBA, in conjunction with previous studies, identified volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and metals contamination in Site soil due to historical Site activities. Groundwater was noted to be impacted by PAHs and trichloroethene (TCE), which poses a potential vapor intrusion risk to future on Site buildings.
Following the TBA for EPA, in 2017, Nobis prepared a Corrective Action Feasibility Investigation (CAFI) and Corrective Action Plan (CAP) for the Putnam Block Site on behalf of the Bennington Redevelopment Group (BRG). Nobis prepared the CAFI and CAP in accordance with Vermont Department of Environmental Conservation (VTDEC) requirements and guidance provided in the VTDEC Investigation and Remediation of Contaminated Properties Rule (IRULE) document. The CAFI/CAP Report used proposed redevelopment plans to identify suitable remedial alternatives for the planned site redevelopment. Nobis incorporated newly collected and previous Site data to develop remedial cost estimates.
As required elements of the Brownfields program, Nobis prepared a Community Relations Plan (CRP) and attended public meetings relative to the Brownfields Cleanup and Site redevelopment. The CRP included a Site description, a project schedule, and summaries of the CAFI/CAP Report, proposed remedial activities, potential impacts to the surrounding community, and the Public Meeting process. Nobis completed multiple Phase I ESAs in accordance with ASTM E 1527-13 between 2017-2019 to provide due diligence for property transfers between various stakeholders.
The first phase of remedial actions, completed by Nobis and approved by VTDEC included the removal and on-site management of 634 cubic yards (CY) of PAH and metals-containing soils, implementation of an Activity and Use Restriction to cost effectively manage contamination to remain on-site, groundwater monitoring for natural attenuation, and future soil gas mitigation systems to control vapor intrusion into residential structures, and removal of two (2) underground storage tanks (USTs) and associated gasoline impacted soil. Because some soil was impacted by petroleum, Nobis assisted the developer to apply for and receive payment through the VT Petroleum Cleanup Fund (PCF) for follow up soil and groundwater sampling.
The second phase of remedial actions included the delineation and evaluation of soil located on the western potion of the site that was impacted with elevated levels of trichloroethylene (TCE). Nobis defined the extent and pre-characterized the soil, such that live-loading and immediate shipping off-site for disposal could occur in accordance with the approved CAP and Community Relations Plans (CRP). In the fall of 2023, 2,700 tons of soil was disposed off site and the soil impacted with low levels of PAHs, was used as approved backfill at the bottom of the TCE excavation area. Due to Nobis’ pre-characterization services, the TCE impacted soil was deemed as non-hazardous waste, which saved the client and EPA more than $300,000. Nobis also prepared a detailed Corrective Action Construction Completion Report for review and approval by the client, VTDEC and EPA.
challenges
- Complex redevelopment challenges included soil and groundwater contamination and a threat to indoor air quality due to the potential migration of soil vapors.
- Redevelopment progress was potentially limited by available funds.
solutions
- Seamlessly transitioned from a successful a Brownfields assessment and cleanup planning for the BCRC to remedial support to BRG during major redevelopment efforts.
- Maximized use of grant funding for assessment and planning. Identified and helped procure alternate funding for cleanup under the VT Petroleum Cleanup Fund.
- Re-used a large amount of soil on-site for beneficial re-use and performed pre-characterizations on other portions of the site to confirm that soil was non-hazardous waste. These effort saved clients and stakeholders more than $400,000.
results
Efficient, budget conscious assessment, remedial planning, and remedial oversight resulted in the rejuvenation of an expansive contaminated Downtown Site. On-going remedial actions continue to support additional redevelopment in the future.
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Posted on March 28, 2024
Civil and geotechnical engineering services to support the design and
construction of a new building on the Concord Hospital Campus.
Nobis was selected to provide civil and geotechnical engineering services for this $70 million Ambulatory Health Care Building on the Concord Hospital Campus. Nobis prepared schematic and full design services and prepared construction documents for the 5-story, 147,000 square foot building. Design work included building layout, vehicle and pedestrian circulation, utility relocation, foundation underpinning, excavation support, and construction observation.
A key Nobis role included utility relocation prior to design of the actual building footprint. The building occupies a former tiered surface parking lot, which consisted of a maze of underground utilities servicing the hospital campus including municipal water and sewer, steam, storm drainage, natural gas, electric, and fiber optic lines. Nobis relocated all of these utility systems so they would not conflict with construction of the new building. Nobis was responsible to pursue needed local, state, and federal permit approvals, perform a subsurface investigation, and provide geotechnical expertise related to the building and facility foundation systems, as well as protective systems for adjacent existing multi-story buildings.
challenges
- Design of a stormwater mitigation system that replicated an existing underground storage tank and added additional storage for the new project. The new underground stormwater system was designed to retain 250,000 gallons of stormwater, while being strategically located so it did not interfere with construction activities associated with the new building.
- The new building was situated adjacent to the existing 3-story Memorial Office Building. The site also dropped in elevation more than 30-feet from north to south and groundwater was present at approximately 5-10 feet below the ground surface.
- The design and construction had to take into account an active 24-hour care hospital. Consideration needed to be given to keeping existing utilities active, maintaining vehicle and pedestrian circulation, mitigation of noise and air (dust and exhaust) pollution, and structural protection of existing active buildings.
solutions
- Nobis designed an innovative stormwater mitigation system that required creating a complex model using a hydrologic software. The system was designed using high strength plastic chambers, surrounded by stone, resulting in a significant cost reduction compared to rebuilding the existing concrete tank.
- Nobis provided guidance and construction oversight on underpinning and lateral support for the existing Memorial building during the construction of the new building’s foundation. The new building’s foundation consisted of a 20-foot concrete retaining wall for which Nobis designed a waterproofing membrane and underdrains to prevent groundwater intrusion into the new building.
- Nobis was actively involved during construction to meet with the owner and contractor to come up with creative solutions to minimize disruption to the existing campus.
results
The project was completed and occupied in 2020.
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Posted on August 11, 2023
Environmental investigation services to evaluate the nature and extent of PFAS contamination resulting from long-time training practices using Class B Aqueous Film Forming Foam.
The Site is a 4.4-acre parcel located at 59 West Bow Street in Franklin, New Hampshire. The Site contains several municipal buildings, including the Fire Station, Firefighter’s Museum, Public Works facility, and smaller ancillary buildings. The Site is located on the peninsula formed by a bend in the Winnipesaukee River, which is a tributary of the Merrimack River to the west. The Site was used from the 1890s to the mid-1930s for the manufacture of heating and lighting gas. From the 1940s until 1969, a natural gas/propane pump station was located at the facility. The existing fire station building was constructed in 1970.
The Franklin Fire Department (FFD) began using AFFF foam for fire suppression around 1973 or 1974. When performing training or maintenance with this apparatus, unmetered amounts of water and AFFF foam would be discharged, typically in the rear of the fire station in the designated Foam Training Area. The runoff from this operation flowed toward local storm drains and unpaved infiltration areas. Routine groundwater sampling for former MGP impacts at the Site revealed the presence of PFAS at concentrations exceeding AGQS. Training was discontinued in 2018 following discovery of PFAS in groundwater beneath the Site.
Nobis completed a Focused Site Investigation on behalf of the City of Franklin. Investigation activities included: a review of Site history and practices relative to Class B AFFF use; installation of three monitoring wells to supplement the existing monitoring network; collection of soil, groundwater, and surface water samples for PFAS analyses; hydraulic conductivity testing; review of potential receptors in the vicinity of the Site; development of a conceptual site model and subsurface cross section; and regulatory reporting. Nobis worked closely with municipal officials and NHDES to prepare a Work Plan for the investigation that met the requirements of Env-Or 600.
challenges
- Development of the conceptual site model was complicated by the presence of multiple subsurface utilities, influence from the Winnipesaukee River, and transitional variation in the subsurface depositional environment.
- Budget limitations required sampling coordination with other environmental assessments ongoing in the vicinity to reduce costs.
solutions
- Use of existing monitoring wells from the MGP site as well as the abutting Ciao Pasta Brownfields site reduced the need for additional monitoring well installations.
- Groundwater sample collection related to the abutting Ciao Pasta Brownfields site included incorporation of PFAS analyses as part of the Brownfields assessment, saving a significant amount of money in laboratory analyses and labor for groundwater sample collection.
results
The results of the investigation indicated the presence of PFOS in groundwater in areas within the immediate vicinity and downgradient of the Foam Training Area. Samples collected from three side gradient locations reported concentrations of PFOA greater the than PFOS, suggesting the possibility that a separate source is impacting the groundwater at those locations. Soil in the immediate vicinity of the Foam Training Area also reported the presence of PFAS compounds, as well as surface water samples in the adjacent Winnipesaukee River.
The overall groundwater contaminant plume extends approximately 800 feet south of the Fire Department with groundwater flow inferred towards the downstream side of the Winnipesaukee River. No drinking water wells or other sensitive receptors were identified during the investigation and the site is being managed currently through ongoing groundwater monitoring.
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Posted on August 11, 2023
Geotechnical and civil/site engineering services to support the design and construction for the addition of a new cooling towner at the Logan Airport Central Heating Plant
Nobis was the geotechnical and civil subconsultant for design and construction services for the addition of a new cooling tower to the Logan Airport Central Heating Plant. The project consisted of the addition of a new cooling tower to supplement the four existing towers that were in place. The subsurface conditions at the site consisted of approximately 15 to 20 feet of unsuitable urban fill and organics overlying 15 feet of natural silt/sand over roughly 150 feet of Boston Blue Clay which got softer with depth. Bedrock was located at a depth of about 180 feet.
The existing cooling towers were founded on 14-inch-square pre-cast prestressed concrete piles; however, use of driven piles for the new cooling tower could generate vibrations that could damage the existing towers. As a result, Nobis recommended the cooling tower be supported on drilled micropile foundations embedded in the Boston Blue Clay crust.
challenges
- Poor soils at the project site
- Presence of extensive existing utilities within the proposed tower footprint which could not be relocated.
- Protection of the existing adjacent cooling towers and extremely tight settlement tolerances.
solutions
- Adjacent existing cooling towers were sensitive to disturbance and vibrations limiting potential driven pile types. Nobis determined that a drilled micropile foundation system would limit impacts to the existing cooling tower foundations (i.e., vibrations and heave) and provide the required capacity beneath the poor soils encountered at the site.
- The micropiles extended to a depth of approximately 60 feet below the ground surface consisting of steel casing in the upper 30 feet and a bonded zone within the lower 30 feet in the stiff clay crust.
- A mat foundation was recommended with full below-grade waterproofing. This consisted of a bathtub-type structure design that ensures the below-grade vivarium space will be completely dry without the need for a permanent dewatering system with pumping.
results
Nobis Group provided both civil and geotechnical services on this Logan Airport project. The additional cooling tower was necessary due to the recent expansions at the airport. In addition to design, Nobis also performed micropile load testing and full-time observation of the production pile installations during construction. The main design challenges consisted of the extremely poor subsurface conditions and proximity of the adjacent cooling tower. The generalized soil conditions consisted of 30 feet of contaminated urban fill and organics overlying 140 feet of Boston Blue Clay (stiff at the top and very soft at bottom) and bedrock. Nobis was able to use the stiff clay crust to our advantage and design a micropile to utilize the resistance of the stiff clay without affecting existing structures. This saved the client hundreds of thousands of dollars from not having to extend the piles to the extremely deep bedrock.
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Posted on August 11, 2023
Selected by the USEPA to conduct environmental investigations and remediation of multiple commercial and residential properties impacted by off-site contamination from the Raymark Industries Superfund Site located in Stratford, CT
Selected by EPA to provide CERCLA-level remedial investigation and remediation expertise at multiple commercial and residential properties that previously received excess fill material from the Raymark Industries plant which had manufactured automotive and heavy brake and clutch friction parts using asbestos, lead, copper, and a variety of adhesives and resins.
The 34-acre Raymark Superfund Site was a manufacturer of automotive breaks, clutch parts, and other friction components and operated until 1989 leaving behind highly-contaminated manufacturing waste which was historically disposed of as fill on-site but, over time, waste material was also disposed of within the Town of Stratford at 60+ residential, commercial, recreational, and municipal properties throughout Stratford. In addition, several wetland areas in close proximity to the Housatonic River were also filled in with Raymark’s manufacturing waste. Primary contaminants of concern include asbestos, lead, copper, PCBs, and volatile organic compounds.
Over several years, Nobis conducted multiple CERCLA-level soil and groundwater remedial investigations to establish the nature and extent of contamination, developed remedial alternatives and feasibility studies, and conducted various related engineering evaluations. Nobis also directed multiple source area removal actions, conducted human health and ecological risk assessments, developed and screened remedial alternatives, and prepared remedial design submittals. Also provided comprehensive community involvement, Proposed Plan, and CERCLA Record of Decision (ROD) support to EPA and other project stakeholders.
challenges
- Highly complex project comprised of 60+ impacted properties organized into nine operable units based upon nature and extent of contamination and proposed remedial actions.
- Multiple project stakeholders, adjacent residential property owners, and a highly engaged Community Advisory Group were focused on this project
solutions
- Conducted multiple remedial investigations and feasibility studies simultaneously in order to achieve stringent EPA Record of Decision deadlines and accelerate planned reuse and redevelopment efforts.
- Provided significant community support including attending community advisory group meetings, preparing fact sheets, poster board charette sessions and to present planned remedial actions, progress, and address community concerns.
- Contamination is located throughout a highly developed urban area and in various settings, including residential, wetlands, tidal creeks and coastal zones.
results
Through our collaboration and partnerships with EPA, Connecticut Department of Environmental and Energy (CT DEEP), the City of Stratford, the community and other stakeholders, several operable units have approved RODs, gone through Remedial Design and now are in active remediation. These efforts will remove impacted material and reduce risks to human health and the environment throughout the community.
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Posted on August 11, 2023
Long-term monitoring, groundwater treatment operation & maintenance (O&M), optimization and enhanced in-situ bioremediation (ESIB) to remediate chlorinated solvent contamination in shallow bedrock.
The Eastern Surplus Company Superfund Site is a 5-acre former junkyard bordering Meddybemps Lake and the Denny’s River. Disposal of hazardous wastes at the Site including dense non-aqueous phase liquids (DNAPL) chlorinated solvents that resulted in extensive groundwater contamination in overburden and fractured bedrock. Under CERCLA regulations, Nobis has provided extensive technical support for the remediation of groundwater that has been impacted with perchloroethylene (PCE), trichloroethylene (TCE), dichloroethylene (DCE) and vinyl chloride.
Between 2007 and 2012, Nobis performed long-term response actions, monitoring, O&M of a groundwater extraction system (GWETS) that treated up to 20 gallons per minute (gpm) of impacted water through filtration, carbon treatment and on-site re-injection.
Starting in 2013, Nobis designed and implemented several phases of an anerobic enhanced in-situ bioremediation (EISB) program to reduce source area contamination in overburden and fractured bedrock. This process included the removal of groundwater that was stored on site, adjusted for pH, dissolved oxygen (DO), oxidation reduction potential (ORP) and then amended with emulsified vegetable oil, electron donors, and Dehalococcoides (DHC) bacteria. This mixture was then re-injected back into the aquifer for in-situ treatment and reduction of the chlorinated solvents into ethene and ethane.
challenges
- During the initial months of the groundwater treatment system operation it was realized that system design was creating in-efficient and incomplete treatment of PCE and other chlorinated solvents, potentially related to residual DNAPL in the fractured bedrock treatment zone.
- Long term monitoring and testing of numerous groundwater monitoring wells was extensive and costly.
- After the first 2 treatment/injection events, several of the injection locations experience bio-fouling, such that effective distribution of amendments was not occurring as planned.
solutions
- To address this issue and optimize the remedial treatment approach, Nobis was able to re-design and reconfigure the system treatment train, storage tank configuration and overall flow patterns to eliminate the shut-downs and increase removal efficiency by more than 25%. In addition, Nobis reconfigured the run patterns for two large compressors which decreased the overall energy usage by 35%, while increasing the effectiveness of the removal process.
- Nobis worked with EPA and the Maine Department of Environmental Protection (MEDEP) to remove 35 wells from the long-term monitoring program that were being sampling twice per year.
- Nobis is designing and working with a drilling subcontractor to rehabilitate and clean the impacted wells, such that injection and distribution of amendments can occur more effectively.
results
Over the years, Nobis’ remedial and optimization efforts greatly reduced annual sampling and travel costs, such that savings of more than $750,000 were realized over a period of 10 years, while still maintaining and meeting overall project data quality objectives.
Based on an initial review of the most recent area wide groundwater sampling program, a decrease of more than 40% of the contaminant mass of chlorinated solvents is estimated as a result of the ESIB treatment. As the geochemical and physical conditions are favorable for continued reductive dechlorination, further decreases of contaminant mass are expected.
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Posted on October 25, 2022
Performed design and construction geotechnical, environmental, and geothermal services for this $375 million research building at the UMass Chan Medical School campus.
This nine-story structure included a 30-foot-deep excavation for below grade laboratory space. Performed subsurface exploration program consisting of 13 additional test borings extending to depths of up to 40 feet into bedrock. The excavation consisted of both soil and bedrock which require blasting. Extensive blasting was performed up to a depth of 30 feet below the ground surface as close as 15 feet away from existing structures. The recommended foundation consisted of a 3-foot-thick concrete mat supported entirely upon bedrock. The below-grade portion of the building were designed as a bath-tub type structure and was fully waterproofed to resist hydrostatic pressure. The soil overburden had elevated levels of Arsenic which are typical of the Worcester region and necessitated disposal to a permitted facility. Nobis also contracted, observed, and monitored the installation of a 505-foot-deep geothermal test well including observation of the production wells.
challenges
- Significant rock removal was required for below-grade construction. Blasting to a depth of approximately 30 feet below grade was required to within 15 feet of existing structures. Hospital operations were extremely sensitive to any blasting vibrations.
- Natural levels of Arsenic are notoriously high in the Worcester region and removal of soil from the site was an issue. The on-site soil had high arsenic levels which required specialized off-site disposal.
- The high groundwater table and required below grade construction required special attention to temporary and permanent ground water control.
solutions
- Heavily monitored for vibration (including up to 7 mobile seismographs and three permanently affixed). Lowered peak particle velocity criteria. Blast size, depth and charge was reduced to accommodate. Blasting was a success.
- Off-site disposal of soil with high-levels of Arsenic were transported to a nearby facility permitted to accept the Arsenic-contaminated soil. This resulted in less project cost than shipping soil to a landfill.
- A mat foundation was recommended with full below-grade waterproofing. This consisted of a bathtub-type structure design that ensures the below-grade vivarium space will be completely dry without the need for a permanent dewatering system with pumping.
results
The new research and education facility is scheduled to open in late 2023.
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Posted on February 23, 2021
Developing new wells on District-owned property and remediating MtBE found at one site
The Mountain Lakes District in Haverhill, New Hampshire provides water to over 320 residential service connections along with a lodge and an office. The District currently obtains approximately half of the supply from its own well sources and purchases the remainder from a nearby water system. The District wishes to reduce or eliminate the amount of water that it purchases by developing a new well(s), preferably on District-owned property.
Nobis was retained to seek a gravel-packed well site that taps a mapped stratified drift aquifer underlying part of the District, as the District has had limited success with bedrock wells in the past. Nobis helped the District investigate all District-owned properties and some abutting properties that overlie the mapped aquifer and installed test wells at selected locations. At one location, a productive test well was found to be impacted by MtBE.
Nobis then leveraged funds available from the New Hampshire Department of Environmental Services (NHDES) MtBE fund and conducted an investigation and remediation program that achieved a progressive reduction in MtBE concentrations, which resulted in laboratory “non-detects” in a few years. With the resolution of the MtBE occurrence, Nobis and the District have renewed consideration of the best options for obtaining new wells on District property to reduce or eliminate purchasing water from the nearby water system. This work is ongoing.
challenges
- Previous District efforts to locate a high-yielding bedrock well had been unsuccessful.
- A mapped overburden aquifer traverses the District but is limited in depth and width, with only a few District-owned properties available overlying the aquifer and having sufficient size for required Sanitary Protective Area radii and setbacks from wetlands.
- MtBE was found in groundwater at one of the most promising District-owned sites.
solutions
- Nobis and the District visited all District-owned properties that overlie the aquifer and some abutting properties to determine their suitability for future water supply development. Test wells or test pits were installed on appropriate properties to refine the list of suitable sites.
- Nobis worked with the District and the NHDES to properly report the MtBE contamination at one of the sites and obtain funding for the District to investigate and remediate the groundwater impact at no cost to the District.
- Using a variety of methods that included geophysics, exploratory drilling, and pumping to remove impacted groundwater, Nobis determined that there were no significant remaining MtBE sources and that a small, local, historical discharge was likely responsible for the observed groundwater impacts. A preliminary pumping program from the most-impacted location and depth significantly reduced MtBE concentrations. A secondary pumping program resulted in non-detections for MtBE.
- In consideration of future District plans, the extraction well installed for MtBE remediation was constructed to Community Water System well standards and is now available for further testing and permitting as a potential new water supply for the District.
results
- To identify locations suitable for developing a new water supply well, several District-owned properties that overlie the overburden aquifer have been assessed, investigated, and ruled out, with a smaller group of sites still in consideration.
- One of the sites was impacted by a historical release of MtBE. Nobis worked with the District and NHDES to successfully address these impacts, at no cost to the District, in a manner that allows further testing in support of developing a new water supply.
- Investigations and discussion to determine the best water supply options and consider costs for the District resumed and are ongoing.
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Posted on April 20, 2018
Design and permit a 3.7 MW solar array constructed upon the Farmington Municipal Landfill
Nobis provided civil and geotechnical engineering, and environmental services for the design and permitting of a solar development located at the Farmington Municipal Landfill. The design supported a 3.7 MW ground-mounted photovoltaic array constructed as two adjacent systems with one array located on the landfill and one on an abutting parcel.
Nobis performed the siting analyses which included historical site data, local zoning and planning regulations, existing infrastructure, environmentally sensitive areas, and related permitting requirements. A geotechnical investigation was also performed to assess site soils and landfill subsurface conditions to accommodate the proposed solar array foundations and structures.
To meet the permitting requirements, Nobis develop the panels, racking switchgear, and conduit layout drawings and developed the regulatory strategy for this project. Permitting was required due to the alteration of terrain which required certain specific soils mapping, storm water modeling, and storm water treatment measures to be implemented.
Challenges
- The solar array footprint encroached into the existing municipal landfill cap footprint and is also adjacent to the existing landfill gas mitigation system.
Solutions
- Nobis was able to partner with the developer and regulators to develop an overall site layout and solar array configuration that optimized the available site area while also complying with the applicable regulatory requirements.
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Posted on April 30, 2018
Remediation and site restoration activities at one of New England’s largest mine Superfund sites
The Elizabeth Mine Site, one of the largest and most intact historic mining sites in New England, operated for 100+ years producing more than 50,000 tons of copper. After closing in 1957, remaining mine tailings, waste rock, and smelter waste resulted in acid rock drainage and dissolved metals resulting in surface water and ecological impacts downstream of the site. To mitigate these impacts, Nobis was selected by the US Army Corps of Engineers to implement the site closure remedy that included the construction of a waste containment system to reduce acid rock draninage discharges from 3 million cubic yards of waste located within two tailing piles. Nobis performed full scale remedial actions that included building demolition/abatement, waste excavation/consolidation, water treatment plant operation and maintenance, and construction of a 43-acre tailing and waste rock landfill and geosynthetic cap.
Nobis excavated, consolidated, and graded over 300,000 cubic yards of waste rock and tailings, constructed the final geosynthetic cap, with 60-mil LLDPE geomembrane, operated the water treatment plant for 5 years, and treated 20M+ gallons of acid mine drainage through an innovative lime amendment rotating cylinder treatment system. 10-acres of wetland mitigation area were constructed and 20-acres of natural habitat were restored.
Challenges
- During the installation of the geocomposite material, Nobis’s QC inspectors identified material defects including rupture between the channels of the drainage net.
- Remedial construction activities were complicated due to National Historic Preservation Act requirements and extreme winter and weather conditions.
Solutions
- Nobis’ QC inspectors visited the geocomposite vendors’ manufacturing facility and determined that the material defects were due to the manufacturing process. Nobis’ recommendations and corrective actions were accepted by the USACE and USEPA and successfully implemented at a cost savings of $62,000.
- Worked with stakeholders to employ best practices that protected and best preserved the site’s historic features and resources. And despite being struck by Tropical Storm Irene, the site experienced only minimal impacts due to proactive emergency planning and employing innovative surface water, capping, and erosion control measures. Nobis was awarded an “Award for Excellence” from the USACE for our storm preparation and response.
Results
Nobis successfully completed cap construction, and operation and maintenance of the water treatment plant during the contract. There were many success highlights of this project including:
- Nobis saved more than $1.5M during remedial actions by effectively implementing 25+ best practices and construction improvements including: optimizing various performance criteria that allowed for the elimination of several geocomposite and drainage piping system components, on-site re-use of shredded stump grindings as slope stabilization, and eliminating the need to import topsoil by finding and using on-site source area soils.
- Nobis completed the cap construction ahead of schedule resulting in reduced client costs. The construction of the cap has resulted in significant and ongoing reductions in both acidity and heavy metals to downstream receptors, demonstrating the ultimate effectiveness of the remedy.
- Nobis successfully implemented several “green” remediation strategies and as a result we received the 2014 USACE National Headquarters Green Dream Team Sustainability Award. Green practices included utilized 210,000 CY of on-site borrow materials that eliminated 14,000 truckloads traveling over local roads, heavy equipment running on biodiesel fuels resulted in 970 tons of greenhouse gas reductions; and other innovative green best practices.
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Posted on April 27, 2018
Design and construction of a multi-use transit-oriented parking facility
To support the growing need for public transit in Massachusetts, Nobis was selected to provide geotechnical engineering and environmental services for the design and construction of a 540-space mixed use parking garage facility – a priority transit-oriented project for the MBTA’s commuter rail system to expand ridership. The project included a three-story, multi-use addition built directly above the parking structure.
From former light manufacturing and railroad support facility use dating back to the 1800s, the site included legacy underground storage tanks and was impacted by past environmental releases. Massachusetts Department of Environmental Protection classified the property as a past disposal site and had placed deeded use limitations on it.
Nobis provided site design services including site grading and utility layout, storm water management, and streetscape improvements. Landscaping plans were also developed that incorporated native and adaptive plant species and low impact design and maintenance considerations. A geotechnical subsurface exploration program and foundation design support was also performed. Construction phase support including construction documentation, contaminated soil management, soil improvements and dewatering support was also provided.
Challenges
- During the design phase, Nobis discovered underground utilities without sufficient as-built drawings and records indicating their presence and function.
- Located in an urban area, it was spatially difficult during construction to stockpile and properly test contaminated soil.
- Challenging soil and subsurface conditions caused settlement concerns at the locations of proposed retaining nearby to the railway and a pedestrian walkway.
Solutions
- To locate and identify the unknown underground utilities, Nobis conducted extensive CCTV inspection and dye testing and successfully incorporated this new data into the overall site utility design.
- Nobis revised their soil sampling protocols whereby they pre-characterized soils at the excavation locations which allowed for the “live loading” and eliminated the need for on-site stockpiling.
- Nobis developed and put in place several new ground improvement recommendations that successfully address on-site settlement concerns for the new structures.
Results
Nobis completed the design and the garage was successfully constructed. The MBTA continues to promote this project as a model Transit-Oriented Development project, and is currently planning for the development of an apartment complex adjacent to this new commuter rail parking facility.
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Posted on April 29, 2018
Beneficial Reuse – Converting An Abandoned Mill into Affordable Housing
The River Bend Mill, located within a historic district of Franklin, NH, was purchased by CATCH Neighborhood Housing with a vision to redevelop the former industrial mill into 45 units of critically needed affordable housing. Nobis was selected to provide the needed engineering and environmental expertise to bring this project to completion.
Nobis conducted an environmental assessment of the property, provided demolition support, and ensured hazardous materials were identified and properly removed throughout this historic building. Nobis’ engineers conducted a subsurface investigation and developed foundation system design recommendations, developed site layout plans, designed the needed utility systems, and implemented a regulatory strategy to usher this project through the necessary permitting processes. Construction documentation and related construction support was also provided by Nobis.
Challenges
- Due to the industrial history of the site, legacy environmental impacts from past contamination existed on-site. As a result, several portions of the site were deed restricted and could not be disturbed.
- Project funding was coming from multiple sources and was conditioned upon many restrictions before the property transfer could occur.
- The mill building was vacant with portions in significant disrepair and unsafe.
Solutions
- Nobis’ overall site design and regulatory strategy successfully accounted for the deed restrictions placed on the property while still achieving the overall redevelopment objectives.
- Nobis successfully completed an expanded site assessment that addressed a complex and broad spectrum of contaminants and exposure pathways that satisfied the funding and property transfer requirements.
- Nobis implemented several additional safety measures and developed design recommendations that included foundation underpinning alternatives due to poor and unsuitable soil conditions beneath the building.
Results
The project was completed and the River Bend Mill successfully redeveloped and put back into beneficial re-use as affordable housing. This project has attracted people to live in the community, encouraged developers to invest in other vacant buildings, connected this neighborhoods to downtown areas, and improved the downtown while retaining the history of its buildings and industrial heritage.
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Posted on April 19, 2018
Use of Innovative Technology to Remediate a Priority Superfund Site
For over 60 years, the Silresim Chemical Corporation Superfund Site operated as a former oil and fuel storage depot and a solvents reclamation business. The company filed for bankruptcy in 1977, abandoning the facility and leaving behind approximately 1 million gallons of hazardous materials in leaking and decaying drums and bulk tanks.
Working under a fast-track schedule dictated by government stimulus funding deadlines, Nobis was selected to complete a $16 million remedial action that included replacing an interim clay cap with a permanent low permeability cap, and implementing in-situ thermal treatment (ISTT) remedy using electrical resistance heating (ERH) to treat contaminated soil and groundwater.
Nobis implemented a patented Electro-Thermal Dynamic Stripping Process (ET-DSPTM) whereby an electrical current is delivered underground via electrodes, generating heat and boiling off organic vapors that are collected through a series of vacuum extraction wells
Challenges
- During a constructability review, Nobis identified design deficiencies in the proposed capping system and overall site grading plan.
- The site was small and required Nobis to install ISTT components with portions of the site that overlapped into the areas of proposed cap construction.
- An insufficient source of electricity existed near to the site jeopardizing the operating the thermal treatment systems.
- An unusually high level of groundwater compounded by extremely tight soils decreased the available unsaturated zone, reduced vapor extraction capabilities, and created pressure events.
Solutions
- Nobis designed and implemented a series of cap construction alternatives without impact to the original construction schedule.
- Nobis developed a sequenced construction schedule which allowed for the disposal of on-site contaminated soil generated during the thermal treatment system construction to be placed below the final cap, thus eliminating the need for off-site disposal. In addition, Nobis determined that a majority of the on-site soil from the interim cap could be reused in final cap construction, thus reducing the volume of material needing to be purchased and transported to the site.
- Nobis proactively coordinated with National Grid to have a temporary 6MW transmission line extended to the site without impacts to the project schedule.
- Nobis installed additional vapor wells to increase extraction rates and multi-phase wells to lower the groundwater table and remove vapors.
Results
Nobis achieved the overall treatment and operational goals set for this project and met the overall project schedule and stimulus funding requirement. The in-situ thermal treatment system provided very favorable results compared to traditional remedial strategies. Prior to this project, the existing groundwater pump and treat system had removed a total of 225,000 lbs of contaminants in 16 years. By comparison, this project successfully removed approximately 87,000 lbs of contaminants in 9 months, significantly reducing site contamination, accelerating overall cleanup goals, and saving future remedial time and costs to the tax payer.
The Silresim Superfund Site is located within an urban area targeted for future investment and redevelopment. These successful remedial efforts implemented by Nobis bring this site one step closer to being redeveloped.
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