In 1991, two state-of-the-art plants opened with three primary functions: (1) to provide an environmentally safe and cost-effective solid waste disposal solution; (2) to recover energy and recyclable ferrous metals; and (3) to reduce the amount of waste subject to landfilling. Each year, the plants generate enough electricity to service about 75,000 households in our community at an energy savings of 2.8 million barrels of oil.
The waste-to-energy plants are a carefully considered solution to meet Broward County's solid waste management needs well into the next century. The plants are part of an integrated system of waste management which includes recycling, waste-to-energy, and landfilling. None of these programs can do the job alone; all three are needed and must work together.
Broward County generates an incredible amount of solid waste. It is estimated that in one year, the amount of solid waste processed at the waste-to-energy plants could fill the area of a football field up to 3½ miles high. There is no way we can effectively dispose of this much waste by landfilling and recycling alone.
The waste-to-energy plants are here through the cooperative efforts of citizens' groups, government, and private industry. During dozens of public meetings and hearings, Broward citizens participated in the decision-making process. The resulting solid waste management plan ties it all together: recycling, waste-to-energy, and landfilling.
Waste-to-Energy Plant Operations
Broward County's two waste-to-energy plants are capable of processing 4,500 tons of waste per day. Here is how it works:
First, the trucks delivering waste are weighed; then they enter an enclosed tipping area where they unload waste into a concrete storage pit. Cranes move and mix the delivered waste, and bulky, processable objects are removed and landfilled. The cranes feed the furnace hoppers located above the back wall of the pit. Air from the pit and tipping area is used for burning the waste (this prevents the escape of dust and odor from the building). Once in the furnace, the waste travels on moving metal grates. A minimum temperature of 1800° F is used, assuring complete combustion and leaving little chance of releasing unburned pollutants.
Hot gases are carried up from the grate area through several boiler tube sections where heat is absorbed to produce steam. The gases pass from the boiler through a scrubber, where a water mist containing lime is mixed with the gases. The gases are cooled and a chemical reaction of the lime with the gases neutralizes any acids and produces particles that can be collected.
Next in the process line is a baghouse that works like a large vacuum cleaner, collecting particles produced in the boiler and scrubber. The cooled and cleaned gases are vented through a stack flue topping out at 200 feet above the ground.
The entire process is guided and monitored by operators from a central control room. All processing activities take place indoors to control dust odors, and to prevent rain water from coming in contact with either waste or ash. Metals in the ash are removed and recycled, while the remaining ash is landfilled in areas adjacent to the plants, called monofills. These monofills have been constructed with multiple liners to prevent groundwater contamination. The water retained by the monofill liner system is used in the plants or sent to a sewage treatment plant for disposal. Wastes that cannot be recycled or processed at the plants are landfilled.
Steam from the boilers powers a turbine generator, producing electricity to run plant equipment. The remaining electricity, about 95% of the total, is sold for use in local homes and businesses.
Broward County contracted with subsidiaries of Wheelabrator Environmental System, Inc., to design, construct, own and operate the two waste-to-energy plants. Wheelabrator is a major resource recovery system vendor with successful projects across the country. They were selected by an open competitive process. Their involvement in the projects allowed the County to take advantage of private enterprise technical expertise and some cost savings.
System Check - Air Quality
System Check - Water Resources
- Daily round-the-clock monitoring and analysis of emissions from the Waste-to- Energy (WTE) plants as well as annual stack testing continuously confirm that all emissions are well within limits allowed by federal and state regulators.
- To reduce mercury emissions, the County launched a cooperative program with local hospitals to begin using nonmercury batteries, resulting in the removal of nearly a ton of mercury a year from the waste stream. To divert button batteries, hundreds of businesses, schools, offices, and residential complexes began serving as drop-off sites. Within the two years of implementation, some 600,000 batteries and an estimated 153 pounds of mercury were removed from the waste stream. These programs, combined with both plants' state-of-the-art emissions control technology and the battery industry's changeover to nonmercury batteries, are helping to protect our environment.
Neither of the plants drains the County's precious water resources. About 80% of the water used at both plants is recycled from different sources. On a daily basis, each plant saves about one million gallons of water through recycling efforts.
At the North plant, wastewater is brought in from the County's North Regional Waste Water Treatment Plant, where it is reused for purposes such as cooling and landscaping. The South plant recycles water from the plant's ash monofill.