Stormwater Treatment at Critical Source Areas Using the Multi- Chambered Treatment Train (mctt)

Robert Pitt Department of Civil and Environmental Engineering The University of Alabama Tuscaloosa, AL 35487 Abstract The Multi-Chambered Treatment Train (MCTT) was developed to control toxicants in stormwater from critical source areas. The MCTT is most suitable for use at relatively small areas, about 0.1 to 1 ha in size, such as vehicle service facilities, convenience store parking areas, equipment storage and maintenance areas, and salvage yards. The MCTT is an underground device and is typically sized between 0.5 to 1.5 percent of the paved drainage area. It is comprised of three main sections, an inlet having a conventional catchbasin with litter traps, a main settling chamber having lamella plate separators and oil sorbent pillows, and a final chamber having a mixed sorbent media (usually peat moss and sand). During monitoring, the pilot-scale MCTT provided median reductions of >90% for toxicity, lead, zinc, and most organic toxicants. Suspended solids was reduced by 83% and COD was reduced by 60%. The full-scale tests substantiated these excellent reductions.