AES utilizes the following technologies to identify, delineate, and monitor impacts to the soil, groundwater, surface water, and sediment. AES is experienced with a large variety of contaminated sites impacted by historic fill, dry-cleaning chlorinated solvents (cVOCs), gasoline, heating oils, diesel fuel, waste oil, Polychlorinated Biphenyls (PCBs), pesticides, herbicides, metals, plasticizers, Polycyclic Aromatic Hydrocarbons (PAHs), and others. Some remedial investigation technologies utilized by AES are described below:
Geophysical Survey
AES may perform a geophysical survey, which includes Ground Penetrating Radar (GPR) and magnetometer (metal detector) scans to identify possible Underground Storage Tanks (USTs), piping, and other subsurface features.
Soil Boring Sampling
Soil cores are collected by direct push or split-spoons and removed from the ground to be screened and samples collected.
Test Pit Sampling
A test pit in soil or weathered bedrock is performed by equipment, which varies in size from a hand shovel to an excavator in order to remove soils to screen the strata and collect samples.
Temporary Well Point Installations
A short-term alternative to permanent monitoring wells are temporary well points. Temporary well points are installed into soil borings and are typically a smaller diameter than permanent wells. Temporary well points can be sampled the same day as installation, but must be removed in 48-hours. Therefore, they are not typically used for long term monitoring.
Monitoring Well Installations
In order to monitor and treat groundwater impacts, AES mayinstall permanent monitoring wells utilizing a variety of technologies and drill rigs of all sizes based on site constraints. Monitoring well installation technologies include:
- Direct Push – A borehole is made in soils using an expendable point. The well screen and casing are installed and then the tooling is removed. This method is typically used for shallow wells.
- Hollow Stem Augers – Sections of hollow stem augers are corkscrewed into soils with an expendable point. The well screen and casing are placed inside the augers and then the tooling is removed. This method is typically used for shallow wells.
- Air Rotary – Compressed air lifts and drops a down-hole hammering drill bit. The soil or bedrock cuttings are then lifted out of the borehole to the surface by the air. This method is typically used for deep wells and bedrock wells.
- Rock Coring – Rock cores are cut using a rotating barrel with a diamond edged blade that is water cooled. Cores are brought to the surface using cables.
- Mud Rotary – Mud rotary uses a rotating drill bit with teeth to cut into soils. Mud is pumped though the drill bit to push out soils and keep the borehole open by using water pressure against the formation. This method is typically used for deep wells in unconsolidated (not bedrock) material.
- Sonic Drilling – Sonic drilling uses rapid vibrations to break up soil and rock. Water is delivered to the drill bit to push soil and rock cuttings out of the borehole. This method is used for shallow and deep wells in soil or bedrock.
Monitoring Well Sampling
AES samples monitoring wells for groundwater sample analysis using 3-well volume purging, low-flow purging, and passive diffusion bags.
Potable Well Sampling
AES can arrange for potable well sampling by a licensed laboratory for receptor evaluation investigations, childcare centers, and Private Well Testing Act.
Indoor Air and Sub-slab Soil Gas Sampling
As part of a vapor intrusion investigation, AES can perform sub-slab soil gas sampling and indoor air sampling.