Solar Pumps Go Horizontal to Dewater Canyon Wells

A West Cast landfill called on Blackhawk's Apollo Solar Piston Pumps™ to dewater remote-site trenches and methane wells in canyons no longer served by electric or pneumatic power.

The closed Class D site includes 6-inch vertical wells to depths of 100 feet with a 1¼-inch gas discharge. More challenging has been dewatering near-horizontal side-slope trenches in the canyons. Some customizing and experimenting with Apollos have been most effective.

In July 2012, the landfill purchased three Apollo units with variable solar charge controls and 180- watt solar panels for dewatering three canyon gas wells. The Apollos successfully dewatered all three wells while running only during daylight hours at roughly 1 gallon per minute.

The site engineer moved one pump to a gas-well trench in the same canyon, and increased the flow to 5 gpm by increasing the foot-valve diameter and installing an experimental high-speed motor and gear configuration. Pumping virtually horizontally, with a 36-inch-diameter casing and pump placement at 300+ feet, the Apollo removed 575,000 gallons in one year.

The second Apollo pump was moved to a trench on the canyon's front face. The engineer added a 240-watt panel, a15M controller and 4 marine batteries to pump at 2.5 gpm with a larger than standard foot-valve assembly. This Apollo configuration maintains the trench in dewatered status, running 24 hours a day but needing a reset after the occasional storm.

575,000 gallons in one year

In 2013, the landfill purchased two additional Apollo pumps with high-speed motors and augmented control boxes. They were installed on the front face, next to the pumps with battery backup. The new pumps have drawn down liquids in the trenches while pumping during daytime, but initially did not maintain consistent gas flow. A battery backup system for the high-speed Apollos was designed to close the gap.

The engineer was pleased he could run five horizontal side-slope and one vertical well on one header for gas recovery. The customized pump drivers remain in use.

Low-grade slope, 24 hr./day