Remediation of contaminated sites is propelled primarily by federally mandated programs (CERCLA, SARA, RCRA, UST, the Clean Water Act), State regulated programs including groundwater protection programs and real estate transfer laws.
The actual time frame from the initial investigation to the start of final cleanup typically ranges from several months for less complicated sites to several years for major industrial Superfund sites containing organic compounds. Remediation services typically include two types of activities: Remedial engineering and remediation. Remedial engineering generally includes investigation of the contaminated site and the design of a cleanup plan. Remediation on the other hand consists of implementation of the cleanup plan by the remedial contractors. |
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Ardaman & Associates, Inc. has extensive experience on providing remedial engineering services to industrial, private, and regulatory clients, and on coordinating remedial contractors and supervising the cleanup activities. |
Organic Contaminants
Organic contaminants may exist in the subsurface in four distinct phases: mobile free product, absorbed phase, dissolved phase, and vapor phase. The free product is known as non-aqueous phase liquid (NAPL) and can be denser than water (dense non-aqueous phase liquid, DNAPL) or lighter than water (light non-aqueous phase liquid, LNAPL). The distribution of contaminants into these different phases is a function of the contaminant properties and site-characteristics. A successful and cost effective remediation of a NAPL site depends on identifying mass and spatial distribution of various phases of contamination. This is specifically true for sites contaminated with DNAPLs such as chlorinated solvents, cycosotes, and PCB oils.
Examples of some of the most commonly occurring contaminants from chlorinated solvents include carbon tetrachloride, chloroform, etrachloroeltylene (PCE), trichloroethylene (TCE), 1,1,1-trichloroethanes (TCA), 1,1-dichloroethylene (DCE), 1,1-dichloroethane (DCA), and chlorobenzenes. DNAPL remediation is further complicated by difficulties in locating the exact location of the DNAPL accumulation, and the flow mechanism that is independent of groundwater flow.
Remedial Engineering Services
The general goal of site remediation is to repair or contain environmental damage and eliminate unacceptable health risks. Ardaman & Associates, Inc. provides comprehensive remedial engineering services that follow a phased and cost effective approach. Based on the complexity of contamination, our approach and the associated services normally include the following work elements at varying degrees of sophistication. |
Project Management
We believe a team approach and strong project management are essential to effectively remediate a site on schedule. Based on the complexity of a project, we construct a project team consisting of diversified professionals (i.e. engineers, scientists and technicians) and client representatives. We emphasize cost effectiveness and client satisfaction without sacrificing technical integrity.
Contamination Assessment
A comprehensive site assessment along with a risk assessment, specifically for DNAPL sites, is critical to identifying the type and extent of contamination and to develop a cost effective remedial action plan. At Ardaman & Associates, we realize the significance of phased approach for site assessment, and accordingly provide a wide spectrum of a hydrogeological and remedial investigation services to tailor specific needs of a site and the client.
Remedial Action Plan
We understand the interdependence and feedback process of contamination assessment and remedial action plans. Based on the findings of a contamination assessment, we identify remediation phases (vapor, soil, groundwater and free products), and develop remedial or corrective action measures. The needs for source and migration control are evaluated for effective design of a remedial action plan. We evaluate the cost effectiveness of an integrated approache that addresses interim and final remedial measures.
Remedial Technology Assessment
Based on the availability, suitability and cost effectiveness, we evaluate the applicable treatment and containment technologies for source control, migration control, interim measure(s) and final measure(s). Both the established and innovative (emerging) technologies are examined during the selection process. Often times emerging technologies are crucial in the timely and cost effective cleanup of DNAPLs.
Remedial Design
We conduct feasibility and treatability studies for contaminated sites and prepare conceptual design for site remediation. In addition to technological viability, regulatory and site-specific considerations are appropriately weighed during this process. After the conceptual design, we perform or coordinate the detailed design for remedial construction.
Remediation
We provide professional services to act as a liaison between remediation contractor(s) and our client(s). We will coordinate, supervise, and provide quality control monitoring during the remediation phases.
Remedial Technologies
The following is a partial list of available remedial technologies for remediation of various phases of contamination. These technologies may be carried out singularly or in various combinations. The principles behind the remedial technologies fall into one or more of the general processes such as containment, collection, and treatment/disposal.
Migration Control Technologies
- Well Systems
- Interceptor Trenches
- Aeration Curtains
- Stabilization / Solidification
- Physical Barrier
- Sheet Piling Walls
- Grout Walls
- Slurry Walls
- Capping
Source Control Technologies
- Volatilization
- Biodegradation
- Leaching
- Vitrification
- Excavation / Treatment / Disposal
- Physical / Chemical Treatment
- Land Treatment
- Thermal Treatment
- Solidification
- Capping / Encapsulation
- Contained Recovery
Treatment Technologies
- Soil Washing
- Soil Mixing
- Incineration
- Bioremediation
- Thermal Desorption
- Photochemical Oxidation
- Air Sparging
- Bioventing Soil Vapor Extraction
- Solvent Extraction
- Carbon Absorption
- Landfilling
- Ultrafiltration
- Reverse Osmosis
- Chemical Precipitation
- Biological Treatment
- Air, Steam & Gas Stripping
- Ion Exchange / Sorption Process
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