Innovative Stripping Chamber Solves Odor Problems for a Pump Station in Ottawa

An odor control technology evaluation was conducted as part of the Munster Hamlet Sanitary Pump Station and Forcemain Design which considered vapor and liquid phase solutions to meet the project objective of odor and corrosion mitigation at the receiving pump station. The extremely long hydraulic retention time in the Munster forcemain provided an ideal anaerobic environment for the generation of high concentrations of dissolved sulfide and hydrogen sulfide gas. Existing odor complaints at the receiving pump station on top of extremely high modeled H2S gas concentrations from the Munster forcemain forced the project team to develop an innovative solution.Ultimately, an aerated stripping chamber with a biological vapor phase treatment system was selected as the most appropriate alternative. The aerated stripping chamber was equipped with a coarse bubble diffuser system to promote turbulence and stripping of hydrogen sulfide gas from the forcemain wastewater prior to discharge into the existing Richmond Pump Station (RPS). The process effectively stripped dissolved sulfide from solution and re-introduced dissolved oxygen back into the wastewater, freshening the wastewater entering the RPS wet well and forcemain.This paper will present operating data related to dissolved sulfide, temperature, pH, ORP and dissolved oxygen of the wastewater entering and exiting the stripping chamber as well as the performance of the two stage biological odor control system treating air from the stripping chamber and the receiving RPS wet well. Additionally, sizing criteria and performance history of the RPS odor control system will be discussed. Since commissioning and acclimation, the RPS stripping chamber and biological odor control system has effectively stripped odors from the wastewater and removed those odors before releasing them to atmosphere.