Factor Analysis of H2S Emission at a Wastewater Lift Station: a Case Study

摘要

Odor and corrosion are common problems in domestic wastewater collection, transportation, pumping, and treatment processes. Based on the comparison among odorous compounds and onsite observations at a wastewater lift station, H sub(2)S is more likely to have caused the odor and corrosion problems than methanethiol and other organic sulfides. The field data from both air and wastewater quality monitoring demonstrated that more H sub(2)S (1 ppmv) was formed at a more negative redox potential, lower pH, and a higher temperature of wastewater. Since the lower detection level of most current analytical techniques is much greater than humanu27s smell and the reference concentration for adverse health effects, automatic monitoring on the threshold of H sub(2)S formation provides a mechanism to trigger control techniques only when necessary for cost saving purposes. Based on Gibbs free energy, a more negative redox potential is required to form H sub(2)S with an increase in pH and a decrease in temperature and SO sub(4) super(2-) concentration. However, pH effect is more significant than both temperature and SO sub(4) super(2-) concentration for H sub(2)S formation. It is recommended that H sub(2)S control techniques be started when the redox potential is below -44 mV, the pH is lower than 5.6, and the temperature is higher than 11.5 degree C to control H sub(2)S below the reference concentration. Corroded concrete particles were examined by X-ray diffraction, which showed that the dominant crystal form was quartz.