Blackhawk side-slopes take over
for crusty submersibles after hot,
aging landfill adds gas system

The Blackhawk Tridents proved to be the right pump for the job. "After chasing my tail for years, I realized I was wrong," the engineer said. Despite the high head, a low-flow pump that worked continuously proved to be what was needed. The side-slope risers were running efficiently at 60-65 psi.

Installation was easy. "In fact, we did it ourselves and eliminated contractor costs," the gas manager said. "The units are modular and pretty simple." Maintenance, too, has been easy and inexpensive. "We’ve experienced maintenance intervals of six months, vs. one month for the others," he said. "That speaks for itself."

The landfill owners are sticklers for compliance and verification. "And once you get a new cell floored in, given our waste stream, you don’t know exactly what’s going on down there," the manager said. "Blackhawk makes it easy."

What is the situation today? "The heavy-duty pneumatics are steady performers and are here for the long haul," the engineer said. "By running steadily, they reached a point where they caught up and now they’re keeping up — a thousand gallons a day. We entered a new cell recently, and we can see they’re keeping up. Blackhawk just keeps going and going and going."

Pump and Well Specs

Model: Blackhawk heavy pneumatic; slide-slope risers
Application: Leachate pumping — hot, crusty
Side-slope riser length: 30 — 80 feet
Well diameter: 18 inches
Casing construction: HDPE
Materials pumped: Highly variable leachate
Total dynamic head: 400 feet
Flow rate: 1,000 gdp
Pneumatics offered surprising low-flow solution.

The gas situation has become even more pronounced recently. Gas generation exceeded estimates, and the landfill is seeing gas generation quickly in new areas. And with the gas comes the challenges in leachate pumping. Even in new cells, issues are developing within months as new pathways are created. "And we’re mindful of the next level of compliance," the engineer said.

The irony for this site, the manager says, is that even though high quantities of gas are being generated, it is being flared off — at least until gas prices rise. "When the costs of building a pipeline are justified, we’ll be ready with great supply."

Landfill Facts

Size: 207 acres
Type: Subtitle D linear system
Capacity 41 million cubic yards
Materials accepted: Heterogeneous — Trash, construction debris, sludges, ash, bio solids, etc.
Characteristics: harsh, hot, highly volatile
Opened: Mid 1980s, expanded mid 2000s by 140 acres
Life Expectancy: 40 years; 25 percent full
Tons annually: 800,000
Area Served: Metro and rural areas in Southern State