Turning waste into reclaimed water

Ever wonder what happens when a toilet gets flushed? Inside a nasty, but essential utility.

By BEN MONTGOMERY, Times Staff Writer
Published August 27, 2007

First a warning, then an explanation.

The WARNING: If you're eating breakfast - or lunch or dinner or snacks, or anything, really - read no further. Stop now. Seriously. Put the paper down or skip to the next page until you finish your Cheerios.

Okay?

Good.

If you're still here, consider yourself warned.

What you're about to read is gross, but it's also important. Every month's water bill includes a charge for something that happens that few people ever think about.

"The story," says Hillsborough County Water Resources employee Kevin Grant, "usually starts with a question: What happens when you flush your toilet?"

If anyone knows the answer, it's Grant, who runs the county's wastewater treatment plant on Falkenburg Road. Because he checks gauges and monitors chemicals, you don't spend a lot of thought on what happens after you flush.

First, the big picture: In Hillsborough, seven wastewater treatment plants treat as much as 37.2-million gallons a day.

That wastewater comes from homes and businesses, from toilets, sinks, water fountains, bathtubs, dishwashers and washing machines, through roughly 530 pumping or lift stations and 1,200 miles of pipe.

Grant's plant is a small piece of that giant operation. It serves about 80,000 customers in the greater Brandon area and treats 6-million to 9-million gallons of wastewater each day.

But plant to plant, the functions are basically the same.

So here's the quick version:

When you flush your toilet, if your home is connected to the county's wastewater system, the flush travels through small pipes under your house and toward the center of the nearest neighborhood road.

There it meets a larger sewer line, which is most likely a gravity flow line, meaning it slopes downward and the wastewater runs downhill. On the edge of your neighborhood, the line meets a pump station where the sludge is pumped underground toward the wastewater treatment plant, most likely miles away.

Here's where it gets gross.

When wastewater enters the plant, most fecal matter has dissolved. Most of it.

The first step of the reclaim process comes when the water is pumped over a series of moving screens that remove most solid matter from the wastewater and empty the solids down a chute and into a big waste bin.

Inside the bin is a mountain of, well, stuff that has been flushed.

Deep breath. Hold your nose. Peek over the edge.

Legos. Newspaper bags. Snickers wrappers. Lots of sand.

Sometimes other things - curious things - make it into the bin, Grant says.

Watches? Sure.

Rings? Yep.

Bags of money? Happened once, he says.

G.I. Joes. Goldfish. If you can flush it, it has most likely come through this plant.

But it's not like anyone wants to stand by the bin long enough to search for treasure, he says.

The bin here fills several times a day. Trucks carry the loads to the landfill. The wastewater keeps moving.

After the solids are removed, the water is pumped back into the ground and up into a series of holding tanks

It typically takes a drop of water 24 hours to make it all the way through the treatment process. And in the end, says Grant, the water is clean enough to drink.

About 55 percent of the water is pumped back to neighborhoods and businesses along roughly 240 miles of transmission lines serving more than 12,000 residential and commercial customers, according to the county. Not to drink, but for irrigation purposes like watering lawns.

Inside the laboratory at the plant on Falkenberg Road sits a fish tank filled with clean water that was once flushed down some unknown toilet.

The water in the tank is clear. The fish are big and healthy.

And that's what happens when you flush.

Ben Montgomery can be reached at bmontgomery@sptimes.com or (813) 661-2443.

FAST FACTS

Laying claim to reclaimed water

The first golf course to use reclaimed water was in Carrollwood in 1978.

First industrial user: Tampa Electric, 1984.

First residential use: Carrollwood, 1994.

Source: Hillsborough County Water Resource Services

[Last modified August 26, 2007, 21:50:37]