Pump and Treat Calculator
| Parameter | Result |
|---|---|
| Groundwater Pore Volume | — |
| Daily Extraction | — |
| 1 Pore-Volume Exchange | — |
| Selected Exchanges | — |
| Parameter | Result |
|---|---|
| Extraction Volume | — |
| Mass Removal Rate | — |
| Operating Time | — |
| Influent Concentration | — |
Mass removal is estimated from extraction flow and influent contaminant concentration. The calculation assumes the entered concentration remains constant throughout the selected operating period.
Important: This is a theoretical estimate. Actual pump-and-treat performance depends on aquifer properties, groundwater flow, contaminant distribution, well configuration, capture-zone behavior, treatment performance and concentration changes over time. Pumping longer than the theoretical pore-volume exchange time may be required because of contaminant tailing and other transport limitations.
What Is Pump and Treat?
Pump and treat is a groundwater remediation method in which contaminated groundwater is extracted through wells or recovery systems and pumped to the surface for treatment or controlled management. The treated water may then be discharged, reused or managed according to the applicable site and regulatory requirements.
Pump and treat systems are commonly used where groundwater contamination needs to be contained, removed or treated over an extended operating period. The effectiveness and duration of a system depend on factors such as aquifer properties, groundwater flow, contaminant distribution, extraction rates and treatment performance.
How Does a Pump and Treat System Work?
A typical pump and treat system extracts contaminated groundwater from one or more wells. The extracted water is then directed to a treatment system designed for the contaminants present at the site.
As groundwater is continuously extracted, additional groundwater moves through the aquifer toward the extraction area. The amount of water that must be extracted and the time required depend on the groundwater volume being addressed and the selected pumping rate.
Pump and Treat Cleanup Estimate
This calculator estimates the theoretical pumping time required for a selected number of groundwater pore-volume exchanges. It uses the contaminated area, saturated aquifer thickness and effective porosity to estimate the groundwater pore volume.
The groundwater pore volume is calculated as:
V = A × b × ne
where V is groundwater pore volume, A is the contaminated area, b is saturated aquifer thickness and ne is effective porosity.
The estimated pumping time is then calculated from the groundwater pore volume, pumping rate and selected number of pore-volume exchanges.
What Is a Pore-Volume Exchange?
A pore-volume exchange represents pumping a volume of groundwater approximately equal to the estimated groundwater volume contained within the defined aquifer area and thickness at the specified effective porosity.
For example, selecting 3 pore-volume exchanges means the theoretical calculation assumes an extracted volume equivalent to three times the estimated groundwater pore volume.
A pore-volume calculation does not mean that all contamination will be removed after one or more pore volumes have been pumped. Contaminant mass can remain in low-permeability zones, sorbed to aquifer materials or otherwise be subject to transport limitations.
Pump and Treat Mass Removal
The mass-removal calculation estimates the amount of contaminant extracted with groundwater using the pumping rate, influent contaminant concentration and operating time.
The basic relationship is:
Mass Removed = Flow × Concentration × Operating Time
The calculator assumes that the entered influent contaminant concentration remains constant throughout the selected operating period. Actual contaminant concentrations in a pump and treat system commonly change over time as groundwater is extracted.
Factors Affecting Pump and Treat Performance
Actual pump and treat performance depends on site-specific conditions. Important factors include hydraulic conductivity, groundwater gradients, aquifer heterogeneity, effective porosity, contaminant properties, contaminant distribution, well location, extraction rate and treatment-system performance.
Contaminant rebound, tailing and mass stored in less permeable portions of an aquifer can also affect the time required to achieve remediation objectives.
Pump and Treat Calculator FAQs
What does a pump and treat calculator calculate?
This calculator provides a theoretical pumping-time estimate based on groundwater pore volume and a contaminant mass-removal estimate based on pumping rate, contaminant concentration and operating time.
How is groundwater pore volume calculated?
Groundwater pore volume is estimated by multiplying the defined contaminated area by saturated aquifer thickness and effective porosity.
Does one pore-volume exchange remove all contamination?
No. A pore-volume exchange is a volumetric calculation and does not represent complete contaminant removal. Contaminant transport, sorption, aquifer heterogeneity and other factors can significantly affect actual remediation performance.
How is contaminant mass removal calculated?
Estimated mass removal is calculated from the extracted groundwater volume and contaminant concentration over the selected operating period.
Does the calculator account for contaminant concentration changes?
No. The mass-removal calculation assumes that the entered influent concentration remains constant throughout the selected operating period.
Can the calculator predict actual cleanup time?
No. The cleanup result is a theoretical screening estimate based on the entered groundwater volume, effective porosity, pumping rate and pore-volume exchanges. Actual remediation time can differ substantially because of site-specific groundwater and contaminant conditions.