ESTIMATING AND CONTROLLING ODORS IN COLLECTION SYSTEMS/TUNNELS WITH VORTEX DROP SHAFTS

The Western Regional Conveyance Tunnel Project (WRTP) is planned for construction in Western Boone County, Kentucky. The collection system upstream of the WRTP is under development, and flows from that system must be conveyed to the new Western Regional Treatment Plant. Northern Kentucky Sanitation District No. 1 (SD 1) is designing the WRTP for the conveyance and wet weather storage of flow to the treatment plant. The tunnel will consist of a 100-foot-long drop shaft (drop shaft no. 1) at the entrance to the tunnel, a 6.8-mile-long, 9.5-foot-diameter storage/conveyance tunnel, a flow control gate structure, followed by a 0.7-mile-long, 8.5-footdiameter storage/conveyance tunnel to the treatment plant. Odor must be controlled to prevent unacceptable levels of odorous emissions generated by and emitted from wastewater in the drop shaft and tunnel that could affect citizens in the surrounding community. Estimates of hydrogen sulfide (H2S) generation in the collection system upstream of drop shaft no. 1, emissions from drop shaft no. 1, and generation and emissions in the tunnel were estimated using sampling data, a computer model that predicts the generation, transport, and fate of H2S in wastewater collection systems, drop shaft air flow estimates using model developed equations, and a mass transfer spreadsheet model. The emissions estimates were used to optimize the selection and locations of the odor control technologies.