Flint spills sewage into river as rain overwhelms pump station, treatment plant

Riverbank park and the Flint River on Thursday, July 6, 2023, in downtown Flint.Brice Tucker | [email protected]

FLINT, MI -- The city says it discharged an unknown amount of stormwater and sewage into the Flint River after the area was pelted with roughly 3 inches of rain in the last 48 hours.

In two separate notices filed with the state of Michigan, the city said its Water Pollution Control Facility, which is undergoing construction upgrades, couldn’t handle the volume of wet weather flows, causing two separate overflows -- from its treatment plant and from a pumping station on Third Avenue.

Flint officials did not immediately provide a volume estimate of the overflows as of 10 a.m. on Friday, Aug. 25.

“While diverting high flow from ... our retention basin, the pressure back-up in the pipe is causing a massive overflow from the manhole and from around the building of the diversion chamber and it is flowing directly into the Flint River,” the city said in one report to the state Department of Environment, Great Lakes, and Energy.

Related: 5 dead, several injured, widespread damage after storms tear across Michigan

In April, Flint’s wastewater system was also overwhelmed by heavy rain, sending raw sewage into the basements of several homes in the city.

The city’s reports say overflows started at the Third Avenue pumping station at approximately 4 a.m. on Thursday, Aug. 24, and were continuing as of 7 a.m. on Friday. The discharge from the pumping station was described as raw sewage while the overflow at the treatment plant was described as having been partially treated by settling, aeration, and disinfection.

Flint’s reports say the city was hamstrung in its ability to hold back the overflows because it took equipment out of service during ongoing treatment plant improvements, forcing it to limit flows from pumping stations and causing the discharge on Third Avenue.

At 12:32 a.m. Friday, the city also reported a discharge of stormwater and partially treated sewage from the treatment plant -- a spill that its report said has ended.

Although the plant has a retention and treatment basin to contain the mix of rain and sewage, it discharged to the river after its capacity was exceeded.

Flint officials said they have notified the Genesee County Health Department, Flint Township and the city of Flushing of the discharges. The Health Department recommends against body contact with the river under high-flow conditions, particularly downstream of the release, west of the Mill Road Bridge at Flushing Road, according to the city’s reports to the state.

Under normal conditions, Flint’s Water Pollution Control Facility on Beecher Road treats all industrial, commercial, and household wastewater in the city before discharging it to the Flint River, downstream of the city.

Built in the 1950s, the plant was designed to treat only 50 million gallons of sewage per day. During heavy rains, the system becomes overloaded because stormwater infiltrates the system, leading to sewer backups or discharges to the river.

In addition to its processing capability, the city also has the capacity to hold about 20 million gallons of excess water temporarily in a large storage basin, but once the tank is full, the excess flows must be discharged or sewage can back up into homes.

Flint’s treatment plant complex also includes 10 outdoor settling tanks similar to massive swimming pools that hold millions of gallons of sewage. The tanks are used to remove solid material from wastewater before it is moved to a clarifying tank for further treatment before finally being discharged to the river.

In 2019, the City Council approved nearly $1 million in contracts with companies to help design long-term upgrades to sewage treatment infrastructure after officials warned that the existing system was at risk of “catastrophic failure.”

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