North America faces significant environmental challenges due to population growth and our aging infrastructure. The need to improve sanitary sewer facilities includes transportation via pipelines or tunnel conveyances for new and upgraded wastewater treatment plants, and the mitigation of combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs).
However, many of the areas requiring new conveyances are either heavily urbanized or established residential neighborhoods. Due to the environmental impacts associated with open cut construction, and the long-term operational concerns associated with pump stations, more municipalities are identifying tunneling methods as their preferred means of installing gravity-based conveyance systems.
A similar solution was established in Cleveland, Ohio as the Northeast Ohio Regional Sewer District
(NEORSD) works to create a solution for its heavy rain events and stop the overflow water from discharging directly into Lake Eire. NEORSD is in the process of installing two storage tunnels that can be dewatered in a 24-hour period in anticipation of back-to-back storm events.
The Easterly Tunnel Dewatering Pump Station project will provide the means to entirely dewater the storage tunnels at the end of each wet weather event and pump combined sewage to the Easterly Interceptor for transport to the Easterly Wastewater Treatment Plant.
Metropolitan provided the project with a seal water system designed to extend the life of the main pumps and cool the seal and the shaft.
The system is designed to allow the water to bypass the seal system until the tunnel reaches a certain level. Standard systems pump continuously.