Rapid economic development and expanding population growth in Southern California has led to an ever-increasing quantity of solid waste. Citizens and businesses in the City of Long Beach alone generate about 368,000 tons of residential, commercial, and industrial waste each year. Long Beach, like other Southern California communities, had historically trucked its solid waste to neighborhoods outside the City for burial in landfills. Closure of a nearby landfill in 1980 led to a realization that Long Beach could no longer rely on the export of its solid waste to other neighborhoods.
The City of Long Beach set in motion a comprehensive solid waste management strategy. A source reduction and recycling program was developed to reduce the amount of waste to be managed and to reduce the consumption of natural resources. Solid waste is sent to the Southeast Resource Recovery Facility (SERRF) where it is processed through one of three boilers. In addition, SERRF performs "front-end" and "back-end" recycling by recovering such items as white goods prior to incineration and collection metals removed from the boilers after incineration. Each month, an average of 825 tons of metal are recycled rather than sent to a landfill.
As a public service and at the request of law enforcement agencies within California, SERRF began destroying narcotics and drug-related paraphernalia in 1992. The program has been a tremendous success. SERRF continues to incinerate an average of 17,000 pounds of narcotics each month. This commitment by the City of Long Beach to assist in the removal of illegal narcotics has saved law enforcement agencies hundreds of man hours and thousands of dollars in alternative disposal costs.
Solid waste is delivered to SERRF in trucks. Each truck is screened for radioactive material while being weighed in by a computerized scale system. The trucks then drive into the enclosed tipping hall where they discharge their load. The refuse is again inspected for unprocessible waste and pushed into the refuse storage pit by a front end loader. The refuse storage pit has 5,000 ton capacity, enough to run the facility for three to four days. The entire storage pit area is enclosed and air is continuously drawn from the pit area and sent through the boilers to remove dust and odor which are destroyed by the high temperatures in the furnace. Carbon filters are used for odor control at times when the boilers are shut down for maintenance.
The waste is lifted out of the storage pit by overhead cranes and dropped into a refuse feed hopper. At the bottom of the feed chute, hydraulic rams push the refuse into the boiler where it is burned under controlled conditions. The heat generated by burning the refuse converts water flowing through tubes in the boiler into steam. The floor of the furnace contains moving grates that push the burning refuse through the boiler. As refuse passes through the boiler, the resultant ash is discharged into a quench tank. The quench tank, which is filled with water, cools and eliminates dispersion of the ash. A Thermal DeNox system injects ammonia into the boiler's burn chamber to control nitrogen oxides.
After leaving the boiler, the combustion gases travel through a state-of-the-art pollution control system. The dry scrubber neutralizes acid gasses such as sulfur dioxide and hydrochloric acid by spraying a lime slurry into the exhaust stream. More than 95% of sulfur dioxide and hydrochloric acid are removed in this process. The reacted lime and ash are removed from the bottom of the scrubber.
The baghouse operates like a gigantic vacuum cleaner. As the air is drawn through the fabric filter baghouse, particulate matter and fly ash get trapped in the bags. Each boiler has a baghouse that contains ten modules with bags made of fiberglass. The baghouse is cleaned by blowing air, in the reverse direction, through the bags. The particulate and fly ash are then removed from the bottom. This process removes 99.5% of the particulate matter in the airstream down to sub-microscopic levels. After leaving the baghouse, the cleaned exhaust gases exit through a 265 foot tri-flue stack. Emissions are monitored by a combination of continuous monitors and periodic stack sampling.
The ash from the furnace, dry scrubber, and baghouse is treated and transported to the landfill where it is used as road base material.
The steam generated from burning the refuse is used to drive the turbine-generator producing electricity. Some of the electricity produced is used to operate the facility and the remainder is sold. The steam used to drive the turbine-generator is then sent to a condenser where it is converted into water and recycled back through the boilers.