Environmental Analysis and Remediation

• Spill Incident
• Release from underground vessel or system
• Regulatory requirement
• Liability concerns related to a property transaction
  • Findings of a Phase One Environmental Site Assessment
  • Data gap identified in a Phase One Environmental Site Assessment
  • A REC identified in a Phase One Environmental Site Assessment

When investigating for Dense Non-Aqueous Phase Liquids (DNAPLs), one must consider the following:

• Not likely to observe free product in subsurface
• Must not create new vertical migration pathways
• Need to be able to discretely sample multiple vertical zones

If you have questions regarding DNAPLs, contact August Mack Environmental at 800.579.0770 and ask to speak to one of our environmental remediation specialists.

• Immiscibility with water - they form separate ‘phases’, eg. Oil & water
• Low solubilities - DNAPL can’t dissolve quickly in groundwater: it may persist for decades before dissolving
• Relatively high densities - DNAPLs are denser than water, and can therefore sink beneath the water table, polluting the full thickness of an aquifer
• Low viscosities - allows rapid subsurface migration
• Toxicity - Many DNAPLs are suspected or...

Remedial approaches to Light Non-Aqueous Phase Liquids (LNAPLs) include the following:

• Hydraulic Methods - Mechanical removal of LNAPL
  • Skimmers in wells – active or passive
  • Pumping – sumps, trenches
  • Vacuum enhanced
• Volatilization Methods - Volatilize LNAPL and capture as gas
  • Soil Vapor Extraction and Air Sparging (SVE/AS)
• Dual-Phase/Multi-Phase Extraction - Remove LNAPL through both hydraulic methods and volatilization methods
  • Could employ vacuum trucks or dual-phase systems.
• Enhancements to the above...

Understanding Light Non-Aqueous Phase Liquid (LNAPL) is important for the following reasons:

• LNAPL is common problem: several hundred thousand petroleum underground storage tanks (USTs) in the United States.
• LNAPL in soil/groundwater serves as continuing source of contamination.
• Can have dangerous physical characteristic – e.g., flammable vapors.
• Can migrate rapidly in subsurface(vertically and horizontally).
• Many LNAPLs are toxic and can cause cancer (e.g., benzene).

1. Landlords should understand tenant activities and provide lease language that shifts liability to the tenant
2. Monitor your property
3. Deal with known problems before discovery by others (regulators, future buyers, etc.)

Vapor intrusion (VI) is the migration of volatile chemicals from the subsurface into overlying buildings. The chemicals associated with VI are the following:

• Volatile Organic Compounds (VOCs)
  • Chlorinated Hydrocarbons, e.g., TCE, PCE, 1,2-DCA, Vinyl Chloride, etc. – drycleaners, manufacturers
  • Benzene & Other Volatile Petroleum Constituents
• Methane – in certain areas of U.S. (e.g., LA Basin)
• Semi-Volatile Organic Compounds (SVOCs) - Less Common

House Enrollment Act (HEA) 1162 requires the Indiana Department of Environmental Management (IDEM) to consider risk-based solutions while evaluating environmental closures. Risk-based closures can include several approaches for example:

• Applying pre-approved closure levels
• Determining site-specific closure levels
• Considering risk of exposure

Another in-situ remedial technology is enhanced bioremediation which is also known as enhanced aerobic bioremediation. Natural bioremediation (breakdown) requires the continued presence of bacteria, nutrients, oxygen and moisture whereas enhanced bioremediation is used to accelerate naturally occurring bioremediation of contaminants in the subsurface. Bioremediation provides a supplemental supply of oxygen to bacteria (normally limiting factor). It can increase the rate of contaminant breakdown...

One of the in-situ remedial technologies available is air sparging (AS). This remedial technology reduces the concentrations of volatile constituents in soils and groundwater by the injection of contaminant-free air into the subsurface saturated zone. It produces a phase transfer of hydrocarbons from a dissolved sate to a vapor phase. Then, the air is vented through the unsaturated zone. It is commonly used with soil vapor extraction (SVE).

The advantages of air sparging are the following:

• Proven...

In the in-situ remedial technology of soil vapor extraction (SVE), the following occurs:

• Vacuum is applied to the unsaturated zone through extraction wells.
• Vacuum causes movement of vapors toward extraction wells.
• Volatile constituents are removed through the extraction wells.
• The extracted vapors are discharged to the atmosphere.

• Proven performance; readily available equipment; easy installation; agency approved.
• Minimal disturbance to site...

The ex-situ pump and treat cleanup technology results in the following:

• Contaminated groundwater is removed from the subsurface by pumping
• It is often used with treatment technologies such as Air Stripping and Granular Activated Charcoal
• Requires understanding of aquifer characteristics (pilot-testing)
• Requires discharge to sanitary (POTW permit) or storm sewer (NPDES)

• Effective for capturing contaminant plumes and...

The ex-situ landfarming technology results in the following:

• Contaminated soils are removed by physical excavation from the ground and placed in open-air cells
• Excavated soils are usually placed onto plastic lining with side berms to contain all soils and moisture
• Contaminants are reduced in the soil by aeration and evaporation or by biodegradation
• Source area of contamination is eliminated
• May require some type of permit for evaporation of contaminants
• Confirmatory soil samples are collected from the...

The Ex-Situ removal and disposal cleanup technology results in the following:

• Contaminated soils are removed by physical excavation from the ground
• Source area of contamination is eliminated
• Soils need to be profiled through an appropriate landfill
• Removal technique requires extensive pre-planning and scheduling
• Confirmatory soil samples are collected around the excavation to confirm effectiveness

• It is effective on all soil...

House Enrollment Act (HEA) 1162 requires the Indiana Department of Environmental Management (IDEM) to consider risk-based solutions to environmental impacts. An important part of risk based thinking is the use of “Multiple Lines of Evidence”. This webinar with summarize risk-based closure thinking and explain how “Lines of Evidence” are used in the process of obtaining environmental closure. You will learn what specific “Lines of Evidence” are most helpful and why.

If a confirmed release has occurred, Environmental Protection Agency (EPA) regulations require that an appropriate cleanup response, or Corrective Action, be conducted

The purpose of the corrective action process is to ensure that releases of petroleum and regulated substances do not threaten human health and the environment. The steps in the process are:

1. Release discovery and reporting
2. Initial Abatement
3. Investigation
4. Corrective Action
5. Incident Closure/No Further Action