Nonbiodegradable organic compounds found in automotive spraybooth scrubberwater

Emissions of volatile organic compounds (VOCs) from painting operations are the largest source of manufacturing emissions for the automotive industry and are costly to control. While investigating the biological degradation o f paint solvents in spraybooth scrubber water as a cost-effective VOC contr ol scheme, it was discovered that a significant portion (10 to 20%) of diss olved organics in the water was not biodegradable. All detected paint solve nts were degraded, however. Therefore, raw and biologically treated scrubbe r water samples were analyzed to identify and quantify the nonbiodegradable organics by combined chromatographic, spectroscopic, and thermogravimetric methods. Results indicate that the nonbiodegradable compounds consisted mo stly of nitrogen-containing organic polymers (more than 70%) and other orga nics. The nitrogen-containing compounds are believed to have come mostly fr om paints and possibly from polymeric detackifiers. Other organics included silicon-containing compounds that might have come from paint additives and maintenance chemicals used at the plant.