Here's a look inside the facility that leaked 24 billion litres of runoff and sewage

The bypass gate that was left openand allowed 24 billion litres of storm runoff and sewage into Chedoke Creekis tucked away under a massive metal plate that leads to a deep, dark tunnel.

And even when the plate is lifted, you can't really see it. You canpeer over the bars that surround the hole, but only partially glimpse an alcove that leads to the gate.

The tunnel is located in a facility housingHamilton's largest combined sewage overflow tank.

This iswhere the untreated waste and stormwater was being stored as it leaked into the creek for over more than four years. And we took a look inside.

The facility isnestled between Main Street and King Street in Hamilton on a swatch of grass called Cathedral Park. The wholesite is four storeys deepand the tank is two-and-a-half storeysdeep. The tankcan store75,000,000 litres of storm water runoff and sewage.

From January 2014 to July 2018, abypass gate in the facility wasleft five per cent open, allowinguntreated wastewater to flow into the creek. The gate is normally meant to be completelyclosed.

Check out Hamilton's largest CSO tank

5 years ago

Duration 1:06

Here's a look at the combined sewage overflow tank that leaked around 24 billion litres of runoff and sewage into Chedoke Creek over more than four years.

Machinery opens and closes the gate normally, silver pistons can be seen rising up plastic tubes when the gate is open.

Andrew Grice, director of water with the city, explained that since the gatewas only open five per cent, the pistons didn't quite makeit to where they could be seen.

The machine is now chained up with a label saying "danger." Grice said that thegate isn't opened at all now.

These systems aren'toperated by hand the machinery is far too heavy for that. Instead, the multiple gates at the facility open and close electronically and can be operatedfrom off site. A control centre above ground turns the power to the pumps and gate machineryon and off.

The public works department also noted that another gate was left open and "likely amplified the spill."

Grice explainedthat the machine that opens and closes this other gate showed a correct number of rotations, which should have meant the gate was closed.

But since thegate had become detached from part of the machine, the rotations were happening but the gate wasn't moving.

Waste travels through sewage pipesto the facilitywith a little help from gravity.

It accumulates inthe facility's "wet well," especially during stormy weather.The tank is meant to store sewage and rainwater during storms so that all the extra volume can be sent for treatment later on. If the tank (and others like it in the city) didn't exist,stormwater runoff and sewage would regularly bypass treatment at the city's sewage plant because it is not able to handle the volume.

In this tank three pumps work to move the waste from this well to the Woodward treatment facility. During large rain events, the wasteistransferred in and out of the larger storage tank. The tank is made up of two cells when the first starts to fill, waste flows into the second, larger tank through gaps in the wall.

If these cells overflow, perhaps due to a massive storm, the waste heads to an overflow trough, whichflows into the Chedoke Creek area. Gricesaid that it would take around 6 hours of a continuous storm to fill the tank.

When the waste leaves behind a mess of plastics,amassive tipping bucket system flushes out the cells by sending waves of water down the stairs.

A motion going before council Wednesday night looks at hiring five people to physically inspect the wastewater system.