Emission of reduced malodorous sulfur gases from wastewater treatment plants

The emission of malodorous gaseous compounds from wastewater collection and treatment facilities is a growing maintenance and environmental problem. Numerous gaseous compounds with low odor detection thresholds are emitted from these facilities. Sulfur-bearing gases represent compounds with the lowest odor detection threshold. Using solid adsorbent preconcentration and gas chromatographic methods, the quantity and composition of reduced malodorous sulfur gases emitted from various steps of the treatment process were determined in wastewater treatment plants in Baron Rouge, Louisiana. Hydrogen sulfide, which is a malodorous, corrosive, and potentially toxic gas, was the most dominant volatile reduced sulfur (S) compound measured (concentration range: 0.017 to 446.9 mu g S/L). Concentrations were not only more than the odor detection threshold of hydrogen sulfide, but above levels that may affect health during longterm exposure. The concentrations of methanethiol (0.008 to 8.7 mu g S/L), dimethyl sulfide (0.003 8 to 26.4 mu g S/L), carbon disulfide (0.006 to 5.70 mu g S/L), and carbonyl sulfide (0.005 to 7.30 mu g S/L) were significantly less than hydrogen sulfide. However, even though emissions of reduced sulfur gases other than hydrogen sulfide were low, previous studies suggested that long-term exposure to such levels may cause respiratory problems and other symptoms.