IMPACTS OF DIURNALLY EXPOSED SLIME LAYER HYDROGEN SULFIDE CONCENTRATIONS IN SEWER ATMOSPHERE

Hydrogen sulfide (H2S) is a major issue in wastewater collection systems. H2S can cause rapid damage to wastewater infrastructure, affects the public’s quality of life through odor issues and is a safety concern for sewer workers. Relatively recent development and introduction of H2S data loggers has shown that H2S concentrations in the sewer headspace demonstrate a diurnal pattern that is not explained by current models. Odor complaints and toxicity are primarily a result of the peak concentration levels and may be more accurately predicted through a better understanding of the diurnal H2S concentration patterns. Biological slime layer grows in the submerged portion of sanitary sewer pipes and is the primary source of H2S in the sewer atmosphere. The diurnal hydraulic cycle common to sanitary sewer systems results in the periodic exposure of a portion of the slime layer. It was hypothesized that the diurnally exposed slime layer impacts the sewer atmosphere concentration of H2S. Utilizing laboratory style tests in a field sewer system showed that the slime layer, when exposed to the sewer atmosphere, will remove H2S. This has not been previously demonstrated and helps explain the diurnal H2S variation in the sewer atmosphere.Civil EngineeringMastersUniversity of New Mexico. Dept. of Civil EngineeringHowe, KerryThomson, BruceSchuler, AndrewHowe, Kerr