Silver Eagle Refinery has installed a full-scale STM-Aerotor® plant from WesTech Engineering to treat its BTEX effluent to below 5 ppm.
Click here to enlarge imageTo prevent any upsets at the wastewater plant, the South Davis Sewer District decided to limit the Silver Eagle Refinery discharge of BTEX to 5 ppm. As the treatment plant had proved, specific organisms could be employed to biologically remove BTEX. With these tighter restrictions, the refinery started to evaluate a pre-treatment program for its waste. Silver Eagle joined with local process company, WesTech Engineering, to conduct a pilot study. The goal was to find a biological system that would significantly reduce the BTEX discharge to meet the limits required by South Davis.
Pilot Plant Equipment
WesTech recommended its compact STM-Aerotor® Pilot Unit. It consists of a 10-foot-long, 6-foot-wide, and 8-foot-tall container unit including a biological stage and an integral settling clarifier. The two-stage tank has an inlet feed into the biological stage, an effluent pipe in the clarification stage, and a drain used for wasting sludge. A baffle wall separates these two areas.
The STM-Aerotor® wheel contains several rows of unique plastic media, a strong structural cage, center shaft, roller chain, and a low-horsepower drive unit. The plastic media has two main functions. First, its hollow interior captures atmospheric air, draws it down into the mixed liquor and releases it for aeration. Second, the media provides a large surface area for the growth of fixed film organisms.