Daniel Company engineers, designs and manufactures a custom BTF system for each plant based on the volume of cubic feet of air per minute (cfm) that the facility needs to process. In a small facility, where the demand is only 2,000 cfm, the system tank could be smaller than an 8 x 8-foot container and skid mounted.
One of the largest biological odor control systems in the country is for the Orange County Sanitation District, Plant 2 in Huntington Beach, Calif. It handles almost 185,000 cfm. That facility consists of 16 biotrickling filters, each 10 feet in diameter and 42 feet tall. “You can see it when you fly over John Wayne airport or on Google Earth,” says Malki. “It’s huge; the whole footprint is larger than a football field.”
Orange County is the Daniel Company’s biggest BTF installation. The BTF serves as the initial filter at this site, sending the emissions it treats into chemical scrubbers for the final cleaning. Use of the BTF filter has reduced the use of chemicals by 90 percent. At another installation in Lubbock, Texas, the BTF has shown a 99 percent efficiency in removing hydrogen sulfide from the emissions. The company has installed BTF systems throughout the United States, most recently in Virginia and Florida.
Each BTF includes tanks, ductwork and dampers engineered to specific sizes, shapes and wall thicknesses. Daniel Company manufactures them from Derakane epoxy vinyl ester resins supplied by Ashland Chemicals. “Ashland is one of our four strategic allies in developing this technology,” Malki says.
The BTF is very labor intensive to construct. “This is not something machine-made,” says Malki. “It’s done by craftsmen who are knowledgeable and who have a lot of experience in the art of fiberglass manufacturing.” For cylinders, the FRP is applied using filament winding techniques; for rectangular structures, they use random chop or hand layup methods.