Dewatering solution for "watered in" landfill gas wells

CAMPBELLTON, FL, JUNE 17, 2019 -- Waste Management's Springhill Regional Landfill near Campbellton, Fla., generates "green" energy by extracting and burning the methane in landfill gas. Its $7 million landfill gas energy (LFGE) plant, with six large Caterpillar engines running 24 hours a day, seven days a week, is capable of producing 4.8 million watts of power. Most of the energy goes to the Alabama Electric Cooperative for distribution to customers. When operating at its peak, the landfill can generate enough energy to supply the electrical needs of 4,000 homes. However, the plant was receiving only enough gas to run two of the six engines. Consulting engineers determined that many of the landfill gas extraction wells were "watered in." High levels of liquid, primarily condensed water vapor, flooded most of the wells' available surface area, reducing gas extraction efficiency drastically. It was not a job for ordinary electric submersible pumps.

The excess liquid had to be pumped down. Temperatures in the wells exceed 140 degrees Fahrenheit, and the presence of dissolved sulfur dioxide, another waste decomposition byproduct, makes the condensate highly corrosive. In essence, the pumps must survive operating in hot sulfuric acid. With their rugged, high-clearance design and unique range of corrosion-resistant materials, air-powered AutoPumps from QED Environmental Systems deliver the durable, reliable performance demanded by challenging applications like this one. AutoPumps were developed specifically for difficult pumping applications at landfills and petroleum and solvent spill remediation sites, and are in use in these applications worldwide. These pumps provide a unique combination of safety, simplicity, and long service life under conditions that challenge other submersible pumps, such as elevated temperatures, high solids levels, high viscosity fluids and corrosive fluids. The facility ordered six AutoPump® AP4 units, followed by another six two months later. By the time all twelve were up and running, the landfill's gas supply was back to nominal levels and all six engines were running at capacity, generating the full 4.8 megawatts.

Nationwide, approximately 650 of the 2,500 existing landfills extract methane for green energy, either to burn it and produce electricity or pipe the gas to industrial consumers who use it to heat and power their facilities. While some sites are too small or too old to produce enough methane for the process to be economically viable, another 500 or so American landfills are reasonable candidates for energy projects. According to the EPA, annual benefits of the operating LFGE efforts include: about 16 billion kilowatt hours of electricity; equivalent energy for electricity for 724,000 homes and heat for 1.3 million homes; saving the equivalent of CO2 emissions from more than 14.9 billion gallons of gasoline consumed.

Installing landfill gas energy plants at the remaining landfill candidates could almost double these contributions to the public good. To bring it closer to home, the average American produces about 4.5 pounds of trash per day. This amount of trash in an LFGE process would produce enough energy to run a stereo for half an hour or light a 60-watt bulb for 15 minutes. As a valuable tool for ensuring the viability of new landfill gas energy projects, Q.E.D. AutoPumps can help to mitigate greenhouse gas emissions while providing energy to more and more communities.