Dura-Pac modular PVC corrugated media from Raschig USA is designed for fixed-film biological treatment applications. With a minimum void to volume ratio of 95 percent, it allows for uniform redistribution of wastewater and air while maximizing contact between the biomass and the wastewater. Modules are composed of thermoformed PVC sheets that are UV protected and resistant to rot, fungi, bacteria, acids and alkalines commonly found in wastewater. The PVC compound is nontoxic to microorganisms and formulated to resist long-term creep and cracking under continuous loading. Available in cross flow (XF) and vertical flow (VF) designs, it includes a full range of modular PVC media geometries for wastewater treatment including complete secondary treatment, nitrification, denitrification, industrial roughing filters, submerged fixed beds and anaerobic treatment systems. 540/862-8426; www.raschig-usa.com.