How did Langan implement a successful sulfate delivery system for remediation at 3093 Broadway?

Remediation is a critical component for brownfield redevelopment and this project at 3093 Broadway in Oakland, California is no exceptioAdditional boreholes 2n. A former car dealership operated at this 3.4-acre site, which is located along the historical Auto Row. During the dealership’s operations, underground storage tanks released petroleum hydrocarbons into the groundwater.

Langan was tasked with mitigating the petroleum hydrocarbons and associated compounds in soil and groundwater. The challenge was to implement a remediation system before construction without endangering the project’s construction schedule or financial viability.

To meet these constraints, Langan designed and implemented a sulfate delivery system within the building foundation. This system introduced a continuous supply of sulfate into the groundwater. The sulfate stimulated native microorganisms to degrade the petroleum hydrocarbons.

Our team drilled 42 remediation borings within the areas of greatest groundwater impacts and backfilled with a mixture of gypsum (calcium sulfate) and other materials. We placed the gypsum below the groundwater table to slowly dissolve and provide an ongoing source of sulfate to the groundwater.

IMG_0751We completed the installation of the bioremediation system prior to construction’s start date. In fact, the process was well underway before the site became inaccessible during site’s earthwork and building construction. We also re-installed monitoring wells at the new ground level for post-remediation monitoring. The approach placed the necessary remediation reagent prior to building construction to avoid the difficulty of placement during or after building construction.

Langan’s environmental and geotechnical teams coordinated closely during remediation design to address potential geotechnical implications. We carefully located remediation borings within the building footprint where they would not compromise the building’s foundation. We also carefully coordinated the gypsum backfill mixture to achieve both the environmental and geotechnical requirements for the project — demonstrating the value of our team’s integrated services for land development.

Langan is proud to work with the developer, CityView, on this well-planned and thoughtful redevelopment. It is a key component in achieving the City of Oakland’s vision under the Broadway-Valdez District Specific Plan to revitalize the neighborhood into a vibrant retail and mixed-use district. Once built, 3093 Broadway will contribute socially and financially to the neighborhood and overall East Bay community for years to come.

Answer provided by Christopher Glenn, PE, LEED GA, Senior Project Engineer
Christopher has 18 years of experience as an environmental engineer and project manager for investigation, mitigation, and remediation sites. He has a broad base of experience with numerous remediation technologies, including biological remediation (reductive dechlorination, aerobic bioremediation, bioaugmentation, bioventing, and natural attenuation), chemical remediation (Fenton’s reagent, permanganate, and zero-valent iron), and physical remediation (soil vapor extraction, air sparging, dual-phase extraction, groundwater extraction, and surfactant-enhanced extraction). Chris is a leader on sustainable engineering and is actively involved in Langan’s corporate sustainability initiative.

What are some of the challenges for new capital projects at existing refineries?

Challenges for new capital projects at existing refineries usually include permitting, below-ground constructability, waste soil management, and health and safety.refinery

Permitting can be a critical path issue, and should be initiated as early as possible in the project design, during pre-permitting meetings with the regulators.  Identification of regulatory jurisdictions early in the planning stages can provide valuable information in siting new facilities. Shoehorning in a new piece of equipment at the refinery requires an in-depth understanding of the subsurface conditions.  This includes identifying utilities and environmental hazards and taking appropriate safety considerations.  The geo-environmental approach works best where the geotechnical and the environmental borings are combined, meaning the holistic solution to the installation of the foundation involves both geotechnical and environmental considerations.

Understanding the constraints of utilities, the potential shoring of utilities, and the handling of the waste soils during construction is critical at the early stages of design development, and may influence selection of foundation type.  The requirements for dewatering, the treatment of the water (whether it can be discharged under the existing permit to the refinery wastewater treatment system), potential migration of existing plumes, and the health and safety issues are all items that require consideration during design.  Ultimately, the design requires a detailed constructability review to confirm that all safety, environmental, risk and engineering issues are covered prior to the completion of the final design.

Answer provided by Rory Johnston, PE, BCEE, Principal
Rory’s consulting career spans almost 30 years, ranging from geotechnical engineering on large industrial projects to environmental investigation and remediation. At Langan, a key part of his role as a Principal is to lead major projects in various market sectors, with an emphasis on oil and gas projects.

Successful Refinery Remediation Requires Special Expertise

LNAPL remediation requires understanding oil refinery history, knowing how to work within current-day operational constraints, and expertly applying the latest science. Oil refining in the modern era dates back to the mid-19th century. Many facilities have been built, rebuilt, and expanded several times to accommodate different product demand and evolving refining technology over this 150-year time period.


Remediation taking place at an oil and gas site

Here are a few of the challenges related to the historical nature of refineries that require an experienced team to successfully recover LNAPL:

  • Variable composition of LNAPL poses different remedial challenges. Older LNAPLs tend to be more viscous or weathered and are typically hard to extract, while fresh fuels often have larger extents due to higher mobility. When older and newer materials comingle, specialized remedial approaches typically need to be leveraged.
  • Groundwater levels are often more variable than at other sites. In addition to the typical seasonal and long-term level fluctuations from climate, refineries have multiple water sources and large differences in use over time that have raised and lowered water levels, which can leave more trapped or stranded pockets of LNAPL at refineries that are less accessible to recovery efforts.
  • Dense development poses access limitations. The location of aboveground structures and below ground obstructions at refineries often limits access for recovery points.
  • Safety requirements take precedence over remediation. Process hazards within an active refinery are paramount, and often limit site access and restrict use of some viable remedial approaches.

Optimizing Remediation Efforts and Saving Money


Environmental Remediation

Our remediation specialists have had success internationally using an approach that leverages traditional LNAPL extraction scenarios, augmented where practical, with technologies from other engineering disciplines. Some innovative Langan approaches include the removal of LNAPL via mobile vacuum enhanced solutions, which allows for a focused remedial approach without a large capital investment, and utilizing “air-lifting” for deep and submerged vertical zone treatment, as typically used for development of deep water wells.

LNAPL remediation requires more than the latest technology. A successful effort must leverage proactive regulatory programs centered around risk-based criteria, extraction practicability discussions, and evaluation and documentation of immobility―while still being focused on the needs of the client. For example, eliminating the LNAPL that accumulates in wells and causes the biggest perception concerns can reap big benefits for clients.

“Our hybrid approach to LNAPL recovery utilizing both innovative and tested methods, delivers remedial solutions with minimized disturbance to ongoing operations.  Also, our fit-for-purpose strategies and regulatory advocacy results in desired business outcomes, meaning the main objective―closures,” says John Loeffel, Langan LNAPL Remediation Specialist.

Time and cost savings are achieved by confirming the source and long-term fate of hydrocarbon impacts, focusing on an end goal determined through revised conceptual modeling, limiting installation of permanent systems or new wells, and receiving stakeholder “buy-in” before commencing an extraction plan. A successful remediation team understands the challenges of refinery work and is focused on delivering a safe, effective solution that delivers on the client’s objectives.

What are your top tips to best manage the risks of contaminated fill during construction projects?

Tip #1: Know that there are risks and liabilities for the owner, developer, contractor and consultants.

Management of known or potentially contaminated fill (and recycled material/debris) poses risks and liabilities to all involved: owners, developers, contractors, and consultants.  There are federal, state, and often local regulations and requirements that apply to managing fill and recycled materials. The site owner, developer,  contractor, and even the consultant who were involved in generating and arranging for the management of exported fill/materials could be liable for its handling and management under federal and state law.

Tip #2: Assess the likelihood of contaminated fill on your project at the outset in the concept development stage.

Construction contracts often presume that excess soil and demolition debris represents only a nominal cost or is viewed as a commodity in the bidding stage of a project. Completing a Phase I Environmental Site Assessment in compliance with the ASTM standard is prudent and can offer some valuable information and liability protection, but is not always adequate to assess potential project impacts related to managing potentially contaminated materials.  Understand the cut/fill balance well in advance of contractor bidding and construction.

Tip #3: Plan ahead to minimize costs and delays.

A fill management plan incorporated into project bid documents, contracts, and construction documents designates responsibility and can be used to allocate costs. Characterizing fill early allows time for practical solutions such as treating material in place or in piles, segregating and routing material to lower cost facilities, consolidating/blending material on-site or re-working the site design. Insuring that your bidders have reviewed the plan and are experienced in the management of fill will get you a price without an “uncertainty premium” (high rates to buffer unknowns) or overly broad exclusions that lead to change orders.

Answer provided by Jeff Smith, PG, Associate
Jeff has over 24 years of experience with property assessments, pre-remedial investigation and strategy, RI/FS, FD/RA, alternative remedial strategies, amended RODs, and exposure pathway and vapor intrusion assessments. His career has required the mitigation of complex technical, regulatory, and legal issues, resulting in development of alternative, cost-effective, practical solutions to environmental problems.

Why is everyone talking about emerging contaminants?

So-called emerging contaminants (ECs) like 1,4-dioxane and per- and poly- fluorinated substances (PFAS) have been receiving much press and public attention lately.  Keeping-up with related news, science and policy developments may seem like an overwhelming challenge, and to some it may be tempting to overlook ECs as a sensational “issue du jour” that will pass with the next news cycle.  However, there are plenty of reasons why everyone is talking and why remediation professionals of all stripes should pay attention.  Here are a few of them.

  1. Inconsistent and Unclear Policies & Regulations. State and federal policy makers have been unable to agree on how (or even whether) to regulate ECs.  It has been almost 20 years since the USEPA promulgated or modified a Maximum Contaminant Level (MCL) for a synthetic organic contaminant under the Safe Drinking Water Act (SWDA).  In the interim, the USEPA has issued unenforceable “health advisory levels” for numerous ECs (like PFAS), and many states have reacted to public pressure by establishing their own, often divergent, numerical threshold values.  The resulting tangle of unclear and inconsistent policies and regulations has confused the regulated community and the general public about actual risks and legal obligations, which in turn has set the stage for controversy and conflict.
  1. Potential for “Re-Opening” Sites. ECs are sparking renewed interest in sites that were previously approved for “closure”.  Previously approved remedies may not have considered ECs for myriad reasons:  a) they were unregulated or not known to be hazardous at the time, b) standards have become more stringent, and c) suitable analytical techniques were either unavailable or unable to resolve concentrations at the levels now being regulated or considered for regulation, some of which are in the parts per trillion (ppt) range (i.e., < 0.1 µg/L).  Regulators have expressed concerns that historically approved remedies should be revisited to consider ECs, to ensure that those remedies remain adequately protective.
  1. Business Environmental Risk. Beyond the attendant regulatory risks and uncertainties, ECs may pose new and potentially significant business environmental risks.  The specter of EC-related toxic tort claims is raising questions about:  a) whether and how companies should assess exposure to EC-related risks, b) whether and to what extent ECs should be considered in transactional due diligence, and c) whether EC-related risks are adequately insured and eligible for claims.
  1. Treatment/Remediation Challenges. By their physical and chemical nature, many ECs do not respond as favorably (or at all) to common, conventional treatment and remediation technologies.  For example, 1,4-dioxane cannot be effectively removed from water via air stripping, while granular active carbon (GAC) is only mildly effective for removing 1,4-dioxane.  Additionally, PFAS such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are mobile in the environment and are not known to degrade at meaningful rates by natural chemical or biological process.  Treating to ppt levels also presents technical challenges and limitations.
  1. Prevalence. Occurrence studies by the USEPA, USGS and various state agencies have identified detectable concentrations of ECs in a significant proportion of public water supplies (PWS) and surface water bodies. For example:
    • 1,4-dioxane was detected in 22% of the PWS tested from 2013 through 2015 pursuant to the USEPA’s Unregulated Contaminant Monitoring Rule (UCMR).
    • PFAS have been detected in a relatively smaller proportion of PWS nationally (2%) but occur more frequently in some regions like New Jersey (detected in 67% of PWS sampled from 2006-2010; see Occurrence of Perfluorinated Chemicals in Untreated New Jersey Drinking Water Sources, NJDEP Division of Water Supply and Geoscience, April 2014).

Additionally, many ECs are not rare or unusual; they have been used extensively in manufacturing processes and consumer products and therefore may have entered the environment from a variety of potential sources.

Answered by Adam Hackenberg, PG
Adam has over 20 years of diverse experience investigating and remediating environmentally distressed sites under various state programs, CERCLA/Superfund, and RCRA. He has been recognized for teaming with clients to evaluate project drivers, define goals and objectives, and develop cost-effective exit/management strategies.

Langan Remediation Summit Recap: “Managing Risk at Legacy Sites – Insights for Success”

The three-day Summit highlighted the latest technical and scientific developments with an emphasis on practical experience and solutions for remediation and redevelopment.

“All presenters were asked to share positive developments and insights in their presentations.  We wanted attendees to understand not only the new issues that we face in remediation, but also the progress taking place to address difficult sites,” said Nick DeRose on the goals for the Summit.  This goal was evident in a collaborative and lively session on “emerging contaminants” (more information on this below), as well as a presentation on current research trends in “Methods for Minimizing Contaminant Rebound Including Current Developments in Back Diffusion Phenomena Research,” a critical concern for on-going remediation projects.

A presentation on “Remediation Risk Management, Including Risk Financing and/or Risk Transfer” offered insights into creative mechanisms to manage remediation liability.

For more information on the presentations, and including obtaining copies, please contact Nick DeRose, Managing Principal at Langan, at or 215-491-6510 .

View the Emerging Contaminants presentation.

View the full agenda and see what you missed!

What were some of the challenges and rewards associated with working in the Golden Gate National Recreation Area and specifically the Presidio of San Francisco?

The most rewarding aspect of working within the Golden Gate National Recreation Area (GGNRA), and specifically the Presidio, is being part of a team that transformed a former US Army base into a spectacular National Park.

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Battery East – Before

Our role as the environmental consultant began more than 16 years ago. At that time, the US Army base at the Presidio had recently transferred to the National Park Service with the Presidio Trust in charge of managing the interior park lands. The National Park Service  would control coastal lands.

Some of our projects included assessing and achieving clean closure at landfills on or near the coast of the Presidio, cleaning up soil impacted with lead near the Golden Gate Bridge, assessing water quality in habitat ponds to support the resurgence of the red-legged frog, and performing remediation on former landfills to assist in bicycle and pedestrian trail development.


Battery East – After

Our biggest challenge was navigating the complex regulatory structure associated with working within the park to clean-up previously contaminated sites and obtain closure. Some of the government agencies with jurisdiction in the GGNRA are the Regional Water Quality Control Board, Department of Toxic Substance Control, Golden Gate Bridge Highway and Transportation District, National Park Service, and Presidio Trust. Another critical component to successfully manage a park project is to understand land use and applicable cleanup standards, whether they be commercial, ecological, recreation, or residential. Different areas of the park have different cleanup criteria, which are based on land use, exposure assumptions, and background conditions.

The GGNRA now consists of over 80,000 acres of ecologically and historically significant landscapes in the greater San Francisco Bay Area.  Over 14 million people visit and enjoy the GGNRA each year making it one of the largest urban parks in the world. We at Langan are proud to have helped open many areas to the public.

About Joshua Graber, CHMM
Joshua is a senior project manager with nearly 20 years of environmental consulting experience.  His responsibilities include geologic, hydrogeologic, and chemical analytical evaluations; Superfund site management; vapor intrusion assessments and mitigation; soil and groundwater remediation; litigation support; remedial excavation, waste classification, and disposal; and technical report preparation. He currently manages the Presidio-wide groundwater monitoring program, GGNRA projects, in addition to other projects in Northern California.