Innovation: Dynamic membrane water filtration
Douglas Hwang has been working on water filtration issues for three decades and he believes the latest product from Waukesha-based startup Corncob Inc. could solve many of the industry’s challenges.
The Corncob II, which uses a membrane technology, can filter many different types of water into potable drinking water in a single step. It can use the concentrated materials removed from water as fuel, limiting the amount of energy needed and potentially taking a wastewater treatment plant off the grid.
“I think we have the answer now,” said Hwang, Corncob president and co-inventor.
Corncob recently held a product demonstration at the Milwaukee Metropolitan Sewerage District facilities along with The Water Council as part of Milwaukee Water Week. Water from the Menomonee River was pumped into Alfie, the nickname for Corncob’s pilot model, and after passing through spinning membrane discs, came out as drinkable water.
Corncob was one of six startups chosen to participate in the fourth year of The Water Council’s BREW Accelerator program. The company received a $50,000 equity investment, space in the Global Water Center and business training and mentorship.
“It’s difficult to find any area of the world, let alone here in the U.S., that doesn’t suffer the impacts of water quality or quantity (issues),” said Karen Frost, vice president of business development for The Water Council.
There are a number of potential applications for Corncob’s product.
The company has quoted a 40-foot-long version of the device for converting raw sewage to potable water for an application in Egypt. A delegation from China National Petroleum Corp. attended the product demonstration and is considering Corncob as a way to treat and reuse fracking water.
A mobile version can go on sewer vacuum trucks that use thousands of gallons of water per day to move sludge toward the vacuum. The mobile Corncob unit could eliminate the need to use freshwater in that application.
Hwang said the Corncob membrane can be customized from microfiltration down to the reverse osmosis level.
“It’s a different degree of filtration that we customize for projects to achieve drinking or irrigation or just river discharge, so it’s flexible,” he said.
Hwang has big visions for what Corncob could become, suggesting it could generate $100 million a year in sales with full production. Manufacturing partners have been lined up in Green Bay, Brookfield and New Berlin, and Hwang said he’s committed to creating jobs and contributing to the economy.
“We are hoping to develop this technology here. This is the right place to do it and it is the right time,” he said.
But there are challenges to overcome before Corncob can grow to those levels. For starters, Hwang and his team need to figure out how to scale the product into a larger model. The membrane discs spin in a pressurized housing and while the pilot model can handle around 5,000 gallons per day, plans call for a version that handles 500,000 gallons per day.
“There are challenges … when we blow this vessel up that big,” Hwang said.
The company also is still searching for its first installation of the Corncob II unit. The Alfie unit has been traveling to different sites and has been tested with 15 different kinds of water, including activated sludge from a wastewater treatment plant, leachate from a landfill and lye water from a food processing plant.
“It’s very consistent,” Hwang said. “To be honest with you, it’s just a membrane that’s doing the job, so concept-wise it’s very simple, but commercial-wise we are in search of our first installation.”
The water that comes out of Corncob can be drinkable as is and depending on the source, should taste just fine. Hwang said this is especially true for a source like river water.
“Sewage? When we are processing sewage, yeah, there is a scent to it,” he said. “Scientifically, it’s drinkable if you go through the tests the EPA requires, but it does have a scent to it and when it comes to that, we probably will put it through activated carbon to just make it taste better.”
Hwang also was asked at the demonstration where the company name originated. He reached for a miniature model of the unit, demonstrating how the membrane filter could be pulled out and replaced. Then he paused and held up just the membrane portion.
“Raise your hand if you see a corncob,” he said.