GRU preps wastewater response to storms 

When hurricanes target Florida, residents jump into action to secure their homes and family, and for more than 100 years, Gainesville Regional Utilities (GRU) workers have also clocked in to keep water and wastewater systems running during storms.

Heavy rainfall can backup lines as lift stations struggle with millions of extra gallons running through the pipes. Even after a storm passes through, GRU's employees may not return to normal operations for weeks.

Rachel Lockhart, acting director of water/wastewater treatment operations, said the utility never knows how a storm will impact operations or where Gainesville might get hit hardest. But the major concern typically lies with the wastewater side rather than delivering water.

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While residents sometimes hear about reducing use of water during a storm, that's not a problem with the water side, Lockhart said, but the wastewater side. As customers use less water, the wastewater system has less water to transport and to treat as millions of extra gallons hit the system.

"While we do this emergency response pretty much all year around—nights, weekends, all those things—it does get ramped up and obviously requires more resources when we're talking about a hurricane," Lockhart said.

To deal with the threats, GRU's teams have protocol for big storms, and even intense rains spread across weeks, to prevent wastewater from backing up into homes and to abide by Florida regulations. That prep work happens all year with preventative maintenance like clearing clogged wastewater lines.

As a storm nears, GRU stocks up on supplies and employees plan to shelter at work. Then, 12 hours before the storm arrives, the wastewater facilities switch to generator power, anticipating that downed lines will cut off the electricity.

Normal operation

The Murphree Water Treatment Plant uses 15 pumps to provide all of Gainesville's water needs—around 23 million to 25 million gallons per day. Lines run the water to homes, businesses and parks in Gainesville, and Lockhart said unless a tree uproots a water line for a section of the city, water services continue reliably in storms.

From every faucet, fountain and toilet, the water then begins its journey as wastewater, headed either to the Main Street Water Reclamation Facility or the Kanapaha Water Reclamation Facility.

GRU uses a combination of gravity, pumps and force mains to move the wastewater several miles or several hundred feet to one of the facilities.

Sloped pipes allow wastewater to move downhill, but after 20 feet below surface, GRU pumps the water back toward the surface to either run for another gravity-powered leg of the journey or into a force main that pushes the wastewater toward the reclamation facilities.

The two facilities purify the water to primary and secondary drinking water quality standards and then discharge millions of gallons of reclaimed water.

At the Main Street location, most of the wastewater goes into the Sweetwater Branch that then heads into Paynes Prairie.

At the Kanapaha location off Tower Road and behind Veterans Memorial Park, the treated wastewater goes to Chapman's Pond, wetlands behind Kanapaha Middle School, irrigation systems at Haile Plantation, or discharged 1,000 feet below ground into the Florida aquifer.

Kanapaha is one of two wastewater facilities in the state allowed to discharge into the aquifer.

During a storm

The Kanapaha facility, built in 1977 and expanded in 2003, averages 10-12 million gallons of wastewater per day and is rated to handle 15 million gallons per day. During heavy rains, the needle passes the average and the facility rating as millions of extra gallons enter.

The large influx of water causes most of the problems: lift stations can't get rid of water faster than it enters and the reclamation facility struggles to purify the wastewater to state standards.

GRU has 177 lift stations across the city, with varying capabilities. All the stations relay information to the Kanapaha facility where staff monitors levels. If wastewater fills the lift station, essentially cylindrical, underground holding tanks, it starts to back up and look for an exit.

"If it starts backing up, it means wastewater in people's houses, so we spend a lot of time and effort with relatively few gaps in between shifts to try to keep that water where it should be—in the pipes and then the lift stations," Lockhart said.

Some pump stations have generators to power itself, but Lockhart said it's not economical for each station. If power goes out to a lift station, wastewater staff haul a portable generator to the station. GRU also uses trucks to pump the lift station and then drive the wastewater to one of the reclamation facilities—4,000 or more gallons at a time.

It's like a game of Whack-a-Mole. Levi Lee, lift stations supervisor, said the crew may run around to different lift stations for days on end.

"It's been up to 50 lift stations without power," Lee said. "So you just go around, drive to this substation, power up your portable generator, run it for 15 minutes to pump it down and go to the next one. Pump it down, maybe an hour or maybe 10 minutes, and then go to the next one."

Lockhart said water often sticks around. She said after Hurricane Irma in 2017 the community was back with football games and activities while staff continued transporting excess water for two weeks after the storm.

Lockhart said GRU staff on the electricity side prioritize downed wastewater systems to get lift stations running again.

Once the wastewater arrives at Kanapaha or Main Street, it passes through a series of treatments with a bacterial bug that breaks down ammonium. Wastewater can take between six and 12 hours to pass through the facility, depending on the level of water entering from the city.

As more gallons enter, it pushes the wastewater already in the facility further along. So, more wastewater means less time within the treatment facility, and if enough water enters, the bacterial bugs don't have enough time to finish the treatment.

If the bacterial bugs fail to treat the wastewater to state standards, then the GRU facility can't discharge it into Paynes Prairie or the Florida aquifer. The partially-treated wastewater must cycle back through for another round.

The Kanapaha has a failsafe when it reaches this point. Chapman's Pond sits a couple hundred feet across the street at Veterans Memorial Park. GRU provides reclaimed water from the Kanapaha facility to fill the pond all year long. If the facility can't treat the influx of wastewater, it can discharge millions of gallons into Chapman's Pond.

The pond is lined along the bottom, and GRU can transfer the wastewater back into the treatment facility once the inflows calm down. GRU staff said the pond has normal reclaimed water for all but maybe two days a year if Kanapaha gets hit with a wastewater surge.

The Kanapaha facility also stocks up before a storm. Staff stores extra bacterial bugs in the system, doubles supply of needed chemicals and ensures it has enough diesel fuel to power itself.

Lockhart said the system is designed with redundancies to ensure service continues as expected.

Considerations for customers

Lockhart said many residents fear water service will stop during a storm, but she said water for the city as a whole remains secure. The Murphree Water Plant has its own generators and extra pumps. The biggest problem, especially in a Tree City, is that an uprooted tree will knock out service to a home.

Because of that, GRU staff says customers can save money by filling up jugs with water instead of buying bottled water from the store.

GRU has pushed the three ‘P's in communications for storm season and beyond. Only Pee, Poo and Paper should enter the wastewater system—no goldfish, markers or feminine hygiene products. GRU has a list of "unflushables" that plug wastewater lines and hurt infrastructure at the reclamation facility.

Clogged lines hurt service during normal operations, but as staff works around the clock in a storm, Lockhart said no one wants to pause operations to remove these "unflushables," including floss, wipes and diapers.

Even though the facilities screen for these products, sometimes items slip past, costing time and money. GRU urges customers to put "unflushables" into the trash, not the toilet.

Reducing water use during a storm can also help. A single, five-minute shower can average 10 to 25 gallons of water, depending on the type of shower head. Less water in the pipes helps lift stations stay ahead.

After the storm passes, avoid standing water and letting kids play in it. It may be rainwater, but it may be backed up wastewater.

Seth Johnson is a Mainstreet Daily News reporter based in Gainesville. He earned a degree in journalism and mass communication and served as editor-in-chief of his school newspaper. Seth is a bookworm and chess nerd, but he tempers these activities by playing sports and biking.

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