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Douglas Larson

Remediation System Operation & Optimization

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The operation of expensive remediation systems, sometimes for decades, is often the result of heterogenous or fine-grained geology, fractured bedrock, restrictive criteria that are regulated down to the part per trillion level, and contaminant mass that is caught up in fine-grain soil making painfully-slow diffusion the primary mass transfer mechanism. Our practitioners are adept at expediting investigations and accelerating site closure through a wide range of innovative technology applications. At many sites with languishing remedial systems, optimization is an option that may improve mass recovery, but it may not be the ideal solution, if contaminant source zones have been inadequately characterized. Geosyntec has repeatedly demonstrated that high-resolution characterization of these zones, followed by targeted source zone removal, can optimize remedy performance and lead to the safe closure of the system. Geosyntec is frequently called upon to critically evaluate and optimize existing systems, providing solutions that range from modification to the unit operations of an ex situ treatment train to reduce chemical and energy costs as influent concentrations decrease; or incorporating flexibility into injection systems by alternating passive and active flow fields or adding additional wells in targeted source zones. When performing remedial design of a new system, Geosyntec applies these same principles of future optimization at the forefront of the design process, positioning the client for long-term savings opportunities. System optimization includes a critical evaluation of the performance monitoring plan. At large sites with sprawling networks of monitoring wells, often sampled quarterly or more, Geosyntec has successfully utilized statistical models to develop streamlined monitoring networks that effectively monitor the system, are defensible to the regulatory community, and can save clients significant monitoring costs. Decades of experience in the implementation of new, emerging, and conventional technology allows our practitioners to frequently bridge the gap between the development and "first-to-field" stages of environmental solutions. In addition, Geosyntec's in-house laboratories provide physical and chemical testing that effectively monitors the performance of treatment processes, technologies, and systems. Our technical evaluation facilities regularly conduct chemical oxidation and bioreactor tests; examine the presence of organics and inorganics in wastewater; evaluate the effectiveness of remediation products; simulate the performance of conceptual designs; and analyze the likely behavior and end point of various treatment processes. Our lab teams communicate regularly to share knowledge and direct internal and external client projects to the most appropriate technology solutions. Working together, Geosyntec's engineers, scientists, and innovators leverage the power of chemical, physical, geological, and biological processes and reactions to detoxify, immobilize, and eliminate exposure risks to a wide range of chemicals in the environment, especially those difficult to treat by more conventional means. Geosyntec uses a combination of standard and developing technologies to create solutions at burdensome sites. These solutions often displace systems that have been running for many years and for which closure may have seemed impossible.

Remedial Design

2026-06-30T09:17:15-06:00March 27th, 2014|Tags: , , , , , , , , , , , , , , , , , , , , , , , |

Geosyntec is a preferred partner for innovative, cost-effective, and successful remediation solutions because we approach each project with technical expertise and creativity. For every client, we develop a clear understanding of how to achieve best-value outcomes using the most appropriate technologies and management strategies for individual projects. When the nature of the problem, like an emerging contaminant, requires a new type of remedy, our professionals set the standard for developing innovative science into novel and effective solutions for environmental remediation. From advanced vapor intrusion evaluation strategies to sophisticated bioaugmentation techniques and beyond, Geosyntec delivers practical environmental management solutions that meet project-specific needs and achieve our clients' objectives. Along with our expertise in treatability and pilot tests, Geosyntec practitioners are adept at conducting feasibility studies that develop, screen, and provide detailed evaluations of alternative remedial solutions for impacted sites. Our studies help clients determine the optimum performance they can expect from a remediation system and the expected cost of implementing a remedy. We also provide detailed remediation system design and design/build services for a wide range of innovative and traditional remediation strategies, including those that employ groundwater pump and treat systems; bioremediation and bioaugmentation solutions; chemical oxidation; the injection of nanoscale zero-valent iron; soil vapor extraction; indoor air venting and treatment; and much more. Geosyntec applies the principles of future optimization at the forefront of the design process, positioning the client for long-term savings opportunities, with strategies like modular unit operations of an ex situ treatment train to reduce chemical and energy costs as influent concentrations decrease, or incorporating flexibility into injection systems such as allowing for alternating passive and active flow fields or the ability to add additional components to target residual source zones. Geosyntec is the leading provider of remedial design services, particularly for complex sites where the challenges – whether from unconventional contaminants, difficult geology and site setting, multi-party groups of responsible parties, or all of the above – make the exit strategy difficult to envision. Our collaborative, global network provides our clients with access to the most talented group of environmentally-focused professionals in the industry. We also approach every project as a time-critical action, recognizing that when our clients require remediation services, they should expect to see the positive results of those actions in a timely manner.

Contaminated Media Investigations & Assessments

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Geosyntec applies reliable and innovative approaches to contaminated media investigations and assessments. We help clients address a wide array of known and emerging contaminants in soil, sediment, and groundwater. We also conduct site evaluations and discover the sources of air emissions, subsurface vapor intrusion into buildings, and contaminants in surface waters. Our assessment specialists include some of the most respected and sought-after professionals in the environmental remediation industry. They possess the experience and technical skills to conceptualize and implement all aspects of contaminated media assessments and remediation programs. Using a multidisciplinary approach, Geosyntec brings together nationally recognized, in-house specialists in civil and geotechnical engineering, ecology and biological sciences, risk assessment and applied toxicology, and earth sciences to address the complex issues associated with contaminated media. Our contaminated site practitioners guide our clients through specialized remediation plans, consult on regulatory strategies, and develop comprehensive cleanup approaches. We address numerous types of media, including contaminated soil, sediment, and groundwater. Contaminated Media Services

Manufacturing

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The pressures on manufacturing clients are complex and often involve many interwoven concerns, including meeting sustainability goals, complying with global regulations, bringing products to market, and managing legacy sites, all while remaining profitable.

Enhanced In Situ Bioremediation of Groundwater Impacted by Chlorinated Solvents at Intensol, LLC Site

2026-04-02T15:51:21-06:00October 29th, 2009|Tags: , |

Groundwater below this four-acre former manufacturing facility was contaminated primarily with PCE and TCE, presumably from historic releases at the site, resulting in the shutdown of three municipal supply wells. One of these supply wells, located approximately 3,000 feet from the site, had been retrofitted with an air stripper in the mid-1990s to limit migration of the groundwater plume. The State accepted a pump and treat remedy to address the source area below the former plant after previous contractors had attempted air sparging and chemical oxidation without success. Intesol's goal was to accelerate the time to closure relative to the pump and treat remedy by identifying alternatives for source area remediation; determining if those alternatives could be implemented quickly; preventing natural groundwater flow from carrying source area contaminants towards the downgradient supply wells; and remediating site contaminants.

Nuclear Metals, Inc. Superfund Site Remedial Investigation and Feasibility Study

2026-06-16T14:30:08-06:00October 29th, 2009|Tags: , , |

Nuclear Metals, Inc. (NMI) used depleted uranium (DU) in the manufacture of penetrators for the US Army. From 1958 to 1985, process waste (DU, nitric acid, and lime) was disposed in an unlined holding basin at this Boston-area manufacturing facility now surrounded by residential neighborhoods. As a result, DU was released to soils and groundwater near the basin.

Full-Scale Bioremediation of Chlorinated Solvents in Groundwater at Six Sites

2026-04-06T11:36:38-06:00October 27th, 2009|Tags: , , , |

The Aberdeen Area at Aberdeen Proving Ground (APG-AA) has operated as an ordnance proving ground since 1917, and throughout its history has been the site of testing of conventional weapons, ammunition, armored vehicles, and other equipment. During a previous Remedial Investigation, chlorinated solvents were identified in groundwater at six sites within APG-AA, collectively known as Other Aberdeen Areas (OAA). The primary contaminant of concern at all six sites is trichloroethene (TCE); however, 1,1,1-trichloroethane (1,1,1-TCA) has also been identified at some sites. The Army's objective for the OAA sites was to rapidly identify, design, build, and implement cost-effective remediation systems that will meet interim remediation goals within five years and drinking water standards within 30 years.

Human Health Risk Assessment and Regulatory Closure at a Site in Irving, Texas

2026-04-02T15:49:53-06:00October 27th, 2009|Tags: |

Chlorinated solvents in soil and groundwater beneath this former manufacturing facility are believed to have originated from a former waste solvent underground storage tank. Soils at the affected property consist of plastic clays overlying approximately 150 feet of competent shale. Limited contaminant migration has occurred through fractures in the clay soils. The client (property tenant) expedited site closure to eliminate financial obligation to property owner.

Bioremediation in Overburden and Bedrock to Address Chlorinated Solvents

2026-04-02T15:50:27-06:00October 27th, 2009|Tags: , |

An accidental release of TCE decades ago contaminated overburden and bedrock at this manufacturing plant. Remediation did not occur until contamination was discovered during an investigation performed as part of a property transaction. Upon this discovery, a pump and treat system was installed by another firm in the suspected source area. This system operated for about a decade, and removed approximately one pint of TCE annually with reported O&M costs of $80,000 per year. Despite groundwater pumping, TCE migrated into the bedrock, moved downgradient and then off-site. TCE and its daughter products eventually began discharging into a stream located on a neighboring property. These seeps have impacted water quality in the stream and threatened to impact water quality in the lake into which the stream discharges. Geosyntec was asked by the client to assist the incumbent consultant in implementing bioremediation in the source area and install a barrier (biobarrier) in bedrock at the property boundary to prevent off-site migration of VOCs.

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