Daniel Company has just completed the design and manufacturing of 16 biotrickling towers and 8 chemical scrubbers for Orange County Sanitation District's odor control system in California.  Each tower is 10 feet in diameter and is approximately 40 feet high.  The biotrickling towers operate as a roughing stage while the chemical scrubbers operate as the polishing stage.  It is estimated that the chemical usage will be reduced by 90%.