The OxyStream oxidation ditch from WesTech Engineering combines vertically mounted, low-speed surface aerators with an oxidation ditch design to maximize oxygen transfer efficiency while maintaining flexibility for power turndown. In addition, it has high side water depths and few required aerators. The vertical slow-speed surface aerator eliminates maintenance-prone horizontal shafts, pillow block bearings and drive units near the water surface. It provides energy savings and produces predictable, high-quality effluent. 801/265-1000; www.westech-inc.com.