Federal standards exist to protect groundwater by requiring some landfills to use plastic liners to collect and treat leachate. Leachate, which is the resulting liquid that drains or ‘leaches’ through a landfill after it rains, can vary widely in composition; depending on the age of the landfill and the type of waste the landfill may contain. When a new wastewater treatment facility was being built right next to an existing landfill, the specifying engineers had to consider how leachate entering their pumping processes might affect the safety of the plant personnel and the pumping equipment.
While the specifying engineers at the consulting design firm were reviewing the requirements of one 15-foot deep sump inside the wastewater treatment plant, they determined that the process required:
- Pumps with explosion-proof motors.
A major Midwest power company needed a new pumping solution for one of its facilities, a 1,900-megawatt coal-fired electric power plant.The Challenge
Coal continues to play a significant role in U.S. electric power generation. The American Coal Foundation reports that nine of every 10 tons of domestically mined coal is used to generate electric power. And more than half of electric power consumed in the U.S. comes from coal-fired power plants.
For these facilities, coal poses wastewater removal challenges, due to coal’s natural properties:
· Coal fines and dust can cause explosions under certain concentrations and conditions. So, coal-fired power plants—like the 1,900-megawatt plant featured in this case study—use water sprinklers to spray coal piles and suppress the dust.
Covanta Energy is one of North America’s largest owners and operators of waste-to-energy plants and other renewable power facilities. Its more than 60 facilities produce electricity for about one million North American homes. The company operates the Covanta Dade Renewable Energy plant in Doral, Florida, for Miami-Dade County. Located not far from championship golf courses that regularly host major Professional Golf Association events, the facility processes some 3,000 tons of municipal solid waste and 1,200 tons of biomass fuel every day.The Challenge
The plant burns trash to produce electricity, boiling water to turn turbines that generate 77 megawatts of power. Formerly operated by Montenay Power Corp., the plant was using a competitor’s pumps in its boiler blowdown, a procedure in which boiler water is purged from the system to minimize the buildup of damaging scale and corrosion.