SANFORD, Fla. — Sanford officials say they have a fix in the works to stop a wastewater treatment plant from overflowing into Lake Monroe.

Earlier in January, the plant located at Seminole Boulevard overflowed twice, spilling millions of gallons into the lake. It led to warning signs being installed telling people to not swim in the water or fish.

A new system upgrade is expected to be done by the end of February that should prevent another overflow.

“We are in the middle of a $4.6 million construction to add new disc filters that are rated at 18 million gallons,” said Sanford Utility Plant manager Richard Casella. “Then we will have the old filters retrofitted, so basically this never should happen again.”

The overflow from the most recent incident on Jan. 20 came to a stop at about 2 a.m.

Casella said cold weather likely caused the plant’s reject ponds to take on too much untreated water.

“The plant is a biological treatment process. It’s how we treat the wastewater,” he said. “It does not like cold weather — basically the cold weather reduces the capacity and capability of the organisms to treat the incoming waste.”

Residents said they are glad to see something is being done, including Tom Fromholz who has lived near Lake Monroe for the past 16 years.

“Well, I have a family that comes down from Indiana every year and they do swim in it,” said Fromholz. “I would like the water quality to be as good as possible.”

City officials said water samples are continually collected and sent to the Florida Department of Environmental Protection for testing. If the tests are clean, they said the warning signs should be taken down in four to five days.