Performance assessment of capture zones generated by PV-powered pump and treat systems

Pump and treat (P&T) is a technology that has been extensively used to remove and/or contain contaminated groundwater. Hydraulic containment of contaminants is accomplished by generating capture zones through pumping of groundwater. An appropriate delineation of capture zones is necessary to design an effective P&T system. P&T systems conventionally operate continuously to achieve steady-state capture zones, which require significant amounts of energy. The use of renewable energies to meet power demands of remedial systems may reduce a project's carbon dioxide emissions. The hydraulic effectiveness of a photovoltaic (PV) powered P&T system without energy storage was characterized using data collected at two different remediation sites, a Dry-cleaning Environmental Response Trust Fund site in Rolla, Missouri and the Former Nebraska Ordnance Plant near Mead, Nebraska. A method to estimate hydraulic containment effectiveness of PV-powered P&T systems without energy storage was developed. The performance of a hypothetical PV-powered P&T system that operates both intermittently by assuming that the system does not include an energy storage component and continuously by assuming that system includes a relatively small capacity energy storage component was analyzed using widely available Typical Meteorological Year 3 data. A methodology to estimate capture zone widths for PV-powered P&T systems without energy storage throughout the continental U.S. as a function of solar insolation data, transmissivity, and hydraulic gradient was developed. Maps depicting predicted capture zone widths for specified transmissivity values and a hydraulic gradient were developed. The applicability of the developed methodology was illustrated with two actual sites where groundwater remediation has taken place.