Insight and Solutions to the Challenges of Site Remediation
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Introduction
Site remediation of locations contaminated with potentially toxic materials is a critical process that has to take into account a number of variables, often under a short time frame. When developing a site remediation plan for a brownfield location, companies have to keep all of these variables in mind so that clean-up can occur in the most effective and efficient way possible. There are many logistical challenges that can occur when planning a remediation process, so companies should be aware of these challenges so they can be avoided when developing and executing the site remediation process. This paper defines the site remediation process and discusses some of the challenges that companies face when developing and implementing a site remediation plan.
What is Site Remediation?
Site remediation is the process of improving a location through the removal of contaminants that have been introduced to soil, sediment, groundwater, or surface water. Site remediation is performed to protect human health, improve the environment, and to improve a brownfield site so that it can be safely redeveloped.
There are many types of contaminants that would necessitate site remediation of soil, sediment, bedrock, groundwater, or surface water.¹ In order to remove these contaminants, there are two primary categories of site remediation: in-situ, where material is treated on-site, or ex-situ, where contaminated materials are removed from the site for treatment or disposal at a separate location. The choice of treatment or disposal depends on the type and concentration of contaminants in the material.
Types of Remediation
SELECTING A REMEDIATION APPROACH
There are a wide variety of remediation approaches² that depend heavily on the type of contaminated media and the type of contaminant:
In-Situ
In in-situ remediation, the contaminated material is treated on site.
SOIL
Biological treatment methods – Bioventing, enhanced biodegredation, natural attenuation, phytoremediation
Physical/chemical treatment methods – Electrokinetic separation, fracturing, soil flushing, soil vapor extraction, solidification/stabilization
Thermal treatment methods – Thermally enhanced SVE
WATER
Biological treatment methods – Enhanced biodegredation, natural attenuation, phytoremediation
Physical/chemical treatment methods – Air sparging, bioslurping, direction wells, dual phase extraction, thermal treatment, hydrofracturing, in-well air stripping, passive/reactive treatment walls
Ex-Situ
In ex-situ remediation, contaminated materials are removed from the site via excavation (soil) or pumping (water) for treatment or disposal at a separate location.
SOIL
Biological treatment methods – Biopiles, composting, landfarming, slurry phase treatment
Physical/chemical treatment methods – Chemical extraction, chemical reduction/oxidation, dehalogenation, separation , soil washing, solidification/stabilization
Thermal treatment methods – Hot gas decontamination, incineration, open burn, pyrolysis, thermal desorption
WATER
Biological treatment methods –Â Bioreactors, constructed wetlands
Physical/Chemical treatment methods – Adsorption/absorption, advanced oxidation processes, air stripping, granulated activated carbon/liquid phase carbon adsorption, ground water pumping, ion exchange, precipitation/coagulation/flocculation, separation, sprinkler irrigation
Containment
Containment involves leaving the contaminated material in place while minimizing migration of the contaminants to uncontaminated soil or ground water.
SOIL TREATMENT METHODS
Landfill caps, landfill cap enhancements
WATER TREATMENT METHODS
Physical barriers, deep well injection
Challenges with Remediation Projects
SELECTING REMEDIATION METHODS
One of the primary challenges with remediation projects is determining the proper combination of remediation techniques that takes into account the contaminant types, the contaminated material types, site geography, and other factors. Since it is unlikely that one single remediation technique will eliminate or neutralize all contaminants in a given brownfield site, a combination of techniques must be designed and implemented to result in successful remediation of the site. Selecting a remediation method depends on the following variables³ :
The form of the contaminate in the environment
Depth and scope of contamination
Transformation by biotic or abiotic processes
Partitioning properties
Mobility factors of the contaminate in the environment
For example, a contaminated site that is in the proximity of a public water source must be remediated in a way that does not further damage the water quality, and returns the quality of water to pre-contamination levels.
ASSESSING AND PREPARING FOR SCOPE OF REMEDIATION
Another challenge is assessing the scope of contamination and ensuring that treatment covers the complete contaminated area. The remediation team has to ensure that the complete volume of contaminated material is treated or removed. If treatment is being performed in-situ, there must be enough remediation materials on hand to treat the entire volume. If treatment is being performed ex-situ, then appropriate containers must be brought in to handle the volume of material being removed and safely contain the contaminant. An adequate storage location or processing facility must be allocated to hold the contaminated material until it is treated; else a permanent storage location must be identified.
REMEDIATION RISK MANAGEMENT
For highly complex brownfield sites, it may not be possible to meet remedial objectives in the near term. Remediation risk management (RRM) looks at project risk events to minimize the probability of occurrence and/or the effects of consequences. RRM is an established practice that involves identification, evaluation, mitigation, monitoring, and reporting. This process can be iterative, as a site is evaluated and remediation progresses. RRM is designed to improve the decision making that takes place throughout the project life cycle, and can be implemented at any stage of the remediation process4.
The project team should identify the risks that are specific to the contaminated site and evaluate each risk from a qualitative and quantitative perspective. Mitigating strategies can be developed and implement for high-risk events. All risk strategies should be monitored throughout the remediation process and new high-risk events identified to keep all risk managed. Implementing RRM can result in improved likelihood of project success, reduced adverse secondary effects on the environment, and reduced time and cost to achieve project goals.
MANAGEMENT OF SITE REMEDIATION
A significant challenge in site remediation is the management of the process and resources involved. Because the overall process of site remediation is interdisciplinary, it's critical for management to establish and maintain clear communication between all involved parties, whether it's field personnel, laboratory technicians, or logistical personnel5. All parties have to avoid misrepresentation when it comes to stating uncertainty. Uncertainty in the extent of contamination can be addressed through statistical sampling methods, staged protocols, and rigorous toxicity testing methods.
Optimization of a remediation project seeks to achieve an effective and efficient site clean up through all stages of the remediation process: investigation, design, remedy, and long term monitoring. Treatments must be effective in removing or neutralizing contaminants, but they also must be efficient in terms of resource usage and cost.
Clean-up activities are regulated by a number of federal and state laws, and there are many laws for worker safety governed by the Occupational Health and Safety Administration (OSHA). Remediation site managers must ensure that the processes put into place for site cleanup meet all of these regulations and that the proper permits for remediation activities have been generated.
DELIVERY LOGISTICS
Site contamination can occur anywhere; in both easily accessible locations as well as remote, hard to access locations. Chemicals can be delivered to a site in a variety of ways. Tanker trucks can bring in chemicals in large quantities, but may not be able to navigate smaller roads. In that case, smaller trucks must be used.
Chemicals can also be delivered in totes or drums when smaller quantities are required or in locations where a truck cannot access.
For example, contaminated soil at a gas station on a major road can be accessed easily by a tanker truck. River locations that are not adjacent to established roads cannot be accessed by tanker trucks, so alternate methods have to be used to get the remediation chemicals to the contaminated site. Sites that are below ground, particularly in an urban setting, may not be accessible by truck at all. In this case, containers must be moved to the contamination site manually.
Mining sites are generally accessible by larger trucks, but may be located far from population centers, so proper storage of the chemicals prior to remediation and storage of contaminated material to be removed after remediation has to be developed. Proper containers have to be brought in that are applicable to the contaminated material, the contaminant, the remediation chemicals, and the amount of time the materials will be in storage.
CHOOSING SITE REMEDIATION PARTNERS
Most companies aren't in the site remediation business, so when site contamination does occur, it's best for these companies to work with experts. Experienced remediation partners use best practices based on their previous remediation projects, so no matter what the situation, the right solution can be applied.
Site remediation partners can:
Help you determine the type of site remediation you need based on the specific contaminants and site characteristics
Quickly access the proper chemicals to perform the right remediation methods for your situation
Deliver the proper chemicals to the remediation site in the proper quantities, no matter what the location. Bulk chemical distributors only offer chemicals in large quantities, so it's important to work with a partner that can provide delivery flexibility.
Manage the remediation of the site from start to finish to meet the requirements of federal and state regulations
Anyone can sell and deliver the proper chemicals for site remediation. However, when you choose partners that understand the challenges and logistics of site remediation, and have the capabilities to address your exact situation, your remediation process will proceed faster and smoother.
Resources
•Â D.M. Hamby, "Site remediation techniques supporting environmental restoration activities—a review", Science of The Total Environment, Volume 191, Issue 3, 22 November 1996, Pages 203–224. http://web.engr.oregonstate.edu/~hambydm/papers/remedrev.pdf.
•Â EPA, "Contaminated Site Clean Up Information", http://www.clu-in.org/remediation/.
•Â Federal Remediation Technologies Roundtable, "Remediation Technologies Screening Matrix and Reference Guide, Version 4.0", http://www.frtr.gov/matrix2/top_page.html.
About Seidler Chemical
For over 100 years, the Seidler Chemical Company has served as a supplier, distributor, blender and re-packager of quality chemicals and ingredients. Founded in 1896 by Alexander Seidler, the company continues to be family owned and operated, treasuring the values of the past while bonding to the pace and passion of today's market place.
If you have a site contamination problem, Seidler Chemicalhas the experience to solve many different types of site contamination scenarios and deliver the remediation materials you need in any quantity and to any location. Searching for a product? Need a special package size or grade? Let Seidler Chemical assist you in your pursuit. Visit our web site http://www.seidlerchem.com, call us at 973-465-1122, or send an email to sales@seidlerchem.com.
