Regional Wastewater Collection System Ventilation Dynamics Investigation

Ferris, Texas

PECI personnel, serving as a subconsultant to a partnered firm, performed a month-long field investigation of gravity sewer ventilation dynamics in parallel 39 and 54-inch interceptors serving multiple customer cities. Headspace H2S, pressure/vacuum levels, and other parameters were measured both with and without the influence of mechanical ventilation. It was shown that mechanical ventilation can produce a vacuum in a sewer headspace over a mile upstream from the pull point, and for a significant distance downstream as well. Headspace H2S Concentrations were reduced 50 to 75% under continuous ventilation, contributing to corrosion management.