When massive wet-weather events hit a combined sewer system, there’s a chance that the wastewater will overflow the system, dumping raw municipal sewage into nearby waterways. That’s called a combined sewer overflow.
Toledo, Ohio, was looking to make this system better. Our job was to contribute the detailed design that would improve the City’s response to heavy wet weather events. But with a narrow design corridor between a fly ash contamination and the abutting streets, we had to get creative.
Our design will allow the first flush of a wet weather event to flow into a storage pipeline (by gravity) and back into the existing East Side Interceptor. But in larger wet weather events, wastewater beyond capacity will be stored within a pipeline. When the new pipeline is full, additional overflow will be permitted to enter the Maumee River.
Once the wet weather event subsides, and the level within the system returns to normal, the storage pipeline is designed to flow back into the sanitary sewer interceptor through regulation gates—giving the City flexibility in controlling the drainage rate.
These capital improvements will provide 1.6 million gallons of gravity-in/gravity-out combined sewer storage, which will reduce activity and allow for the relocation of the combined sewer overflow from the local marina to the main stem of the Maumee River.