Ellingson-DTD installed four pore water removal/dewatering wells within a closed ash basin. One well is a blind (single-ended) configuration, and three wells are completed in continuous (double-ended) boreholes. The blind wells were constructed utilizing the Knock Off (KO) well completion technology. In this drilling/installation method, we used drillable casing to advance a pre-planned bore path to an underground termination point. Upon reaching the end of the bore, the crew pushed the well material down through the center of the casing. When the well material reached the end, it latched onto and pushed the sacrificial drill bit off the drill string. The drillable casing was then tripped out of the bore, leaving the well in its original position. Two of the continuous wells were installed via pilot hole-backreaming operations during 24-hour-per-day operations. Well materials/configurations are detailed below.
| Completion Date | Well ID | Configuration | Materials | Screen Length | Riser Length | Total Length |
| 3-27-2025 | HW-02 | Blind | 4’’, Sch. 80 PVC | 850’ | 120’ | 970’ |
| 5-23-2025 | E-HW-03 | Continuous | 8”, DR11 HDPE | 1,800’ | 126’ | 1,926’ |
| 6-20-2025 | E-HW-02 | Continuous | 8”, DR11 HDPE | 2,460’ | 372’ | 2,832’ |
| 6-30-2025 | E-HW-01 | Continuous | 8”, DR11 HDPE | 2,440’ | 219’ | 2,659’ |
Biodegradable drilling fluid was used for drilling and well installation. Well development consisted of flushing and jetting with an enzyme breaker solution and overpumping with a submersible pump.
Current System Status Well E-HW-01
E-HW-01 is completed as continuous (double-ended) well. The well was designed so the screen section was near the base of the ash, slightly above the native formation. Well materials are 8 in (20 cm) diameter PVC. The entry rise is 100 ft (30.5 m), 2,440 ft (743.7 m) and exit riser of 119 ft (36.3 m) for a total well length of 2,659 ft (810.5 m). The screen aperture is 0.02 in (0.51 cm) cut with two rows at 180°.
After well development and testing E-HW-01 was equipped with a submersible pumping system, variable frequency drive (VFD) controller, and remote telemetry datalogger. The pump is a Grundfos 25S10-7 with a 1.0 hp, 480 V, three phase motor. The pump and motor are designed to produce 30 gpm (1.9 l/s) at 110 ft (33.5 m) of head with a variable flow range of 4-34 gpm (0.25 l/s – 2.1 l/s). The pump is connected to 3 in (7.6 cm) discharge line at a horizontal distance of 860 ft (262 m) from the entry point at a depth of 30 ft (9.1 m) below the well entry elevation.
The data logger consists of an Allen Bradley 820 PLC system that provides the following information on a local data screen or through a remote dashboard.
Flow rate
Totalized flow
Average 24 hr. flow rate
Water level – current conditions and historical
Run time hour meter
The VFD can be set to automatically adjust the pump to maintain a fixed liquid level in the well and can be remotely controlled and adjusted via a cellular connection. Based on conversations with the pump/controller supplier, this installation is the longest installation of a VFD drive for a submersible pump.
