Urban Stormwater Technologies (UST) will be exhibiting its at-source stormwater filtration device, the Catch Basin Insert (CBI), at the Boomerang Alliance’s Beyond Plastic Pollution: Pathways to Cleaner Oceans conference in Sydney at the end of the month.
UST director Craig Rothleitner told Inside Waste the CBI offers a simple but complete disruption to the waste streams that are being dumped in the world’s waterways via stormwater drainge systems.
“I have literally been in thousands and thousands and thousands of drains, and it’s really quite horrific what’s going on. Globally, stormwater is seen as a contaminated water waste and is taken to wetland, lakes, rivers and ocean outfalls as quickly and efficiently as possible with no regard for water quality,” Rothleitner said.
“For every 20 drains being serviced [by us] 10 times a year, we are averaging somewhere between 1.2 and 1.5 tonnes of waste per year. If you put that into context for say Perth, I think there’s somewhere around 100,000 drains emptying into the Swan River. That’s a lot of tonnage of waste. And it’s a lot of tonnage of waste that is recontaminating because it’s still breaking down. We need to stop it getting into the water in the first place.”
Before starting his company Rothleitner spent 10 years working in the dredging industry which he said gave him unique insight into the problems facing our waterways.
“When we went and deepened harbours, the first couple of metres of mud that we always pulled up was this black rotten vegetation – [the same black rotten vegetation] that I’m seeing at the bottom of drains. It’s a cycle that has been going since stormwater systems have been installed,” he said.
“The vegetation breaks down into nutrients. Governments are blaming farmers around the world [for nutrient pollution related to agricultural run-off], but from what we’ve seen, it’s got nothing to do with the farmers. Yes, they are adding something to waterways, but the majority is coming out of stormwater. It is incredible.”
UST’s Catch Basin Insert comes in a range of standard sizes to fit side entry pits, grate drains and round or semi-round drains, but can also be customised to suit any drain. A patent-pending filtration material lines the computer-made basket and support frame which is constructed from 316 marine grade stainless steel.
Mechanical filtration captures the bulk of the waste; anything from vegetation to cigarette butts, plastics to human hair, sand to sediment, “you name it, it’ll collect it,” Rothleitner said. But a further filtration process occurs utilising the very waste that has been captured.
“When the waste enters the drain, the CBI material slows the water down just a little bit. What that’s doing is turning dissolved particulates, into undissolved particulates. It’s already scientifically known that sediment between 63 micron and 300 micron, acts like a natural absorbent ball that absorbs nutrients, hydrocarbons and heavy metals. Our device is not only capturing the bulk of the waste, removing 95% of it at the opening, but the waste that it’s capturing is then further filtering the water on the way through.”
According to Rothleitner, unofficial trials conducted by Singapore’s Public Utilities Board showed the CBI improved drain’s outgoing water quality by 80%. In Australia, Perth’s Hillarys Boat Harbour is one site that has been using CBIs for six years.
“[Hillarys Boat Harbour] has big impermeable carparks full of cars everyday – 2700 bays – so every time it rained up there, the marina was like a big oil slick. We found if we put our device in, and then put another tray underneath it with a product called Mycalex, we’re actually polishing the water of hydrocarbons and heavy metals at the same time. So in the six years we’ve been there they’ve never once had an oil slick in the marina,” Rothleitner said.
In addition to showcasing the CBI, Rothleitner will also be exhibiting his recently developed plastics removal device, which uses conveyor technology to remove plastic from the ocean. UST is also currently working on trials using the same CBI material as a sediment control device for the farming industry.
You can catch Craig Rothleitner speaking about his waterway management technology at 3.25p.m. on day two of the Boomerang Alliance’s inaugural Beyond Plastic Pollution: Pathways to Cleaner Oceans conference held in Sydney’s Darling Harbour from October 30 to November 1.