Few people are more excited about wastewater than Thomas Fudge. He has good reason. He and his colleagues believe they have discovered a way to turn sludge into gold.
Wastewater from places such as breweries and food processing plants cannot be dumped down the drain. Special handling is required and expensive work is often done off-site. Fudge's company, Wase, is offering them an alternative: treating water on-site and getting energy for free.
Recovering methane from organic waste and using it to generate electricity and heat is nothing new. Companies do this not only to squeeze some value out of the sludge, but also to reduce their carbon footprint, since sludge can be a source of greenhouse gases if left to decompose naturally. It's also to reduce it. By sending it to an anaerobic digester and burning the resulting methane, companies can reduce their carbon footprint.
However, Wase isn't building a typical anaerobic digester. The UK-based startup says its system is significantly smaller and can squeeze around 30% more methane from sludge. The volume of indigestible organic waste is reduced by 30% to 50%.
The trade secret is electroactive microorganisms.
“They're absolutely everywhere,” Wase founder and CEO Fudge told TechCrunch. “They're in the ground, they're in sewage sludge, they're in anaerobic digestion systems, but they don't really have an environment where they can thrive.”
Basically, Wase has created a contraption to make these bacteria happy.
In one of Wase's systems, stacks of electrically charged fins called electrodes provide a home for electroactive bacteria to grow. On one electrode, several species cleave hydrogen ions from the sludge. In another method, methanogenic bacteria take that hydrogen and use their extra electrons to bond it to the carbon atom stripped from the carbon dioxide. The system needs to provide a small amount of power to keep things flowing in the right direction. “It's more or less like a traffic light,” Fudge said. The end result is biogas.
Once gas is produced, it is vented and combusted to produce heat and electricity.
Because Wase uses widely distributed microorganisms and supplies them with the electrons they need, the bacteria are happier under a wider range of conditions, Fudge said. Compared to the anaerobic digesters typically used for this work, Wase's system can operate at lower temperatures and a wider range of acidic (or basic) conditions, Fudge said.
“Because they grow much faster, they can break down organic compounds more effectively and quickly.”
Colonies that form on the electrodes are constantly rejuvenated. When old bacteria die, they become food for living things. Each colony contains a variety of species and strains that evolve over time as they become accustomed to the particular sludge they are processing.
Wase is developing a control system to maintain the flow of wastewater through the system to keep the bacteria in top condition. As the bacteria draw electrons from the electrodes, the control system can monitor the current to determine how satisfied the bacteria are.
“It allows for real-time optimization,” Fudge said, which can be used to determine maintenance schedules, automate feeding, and monitor overall system performance. “This allows operators to communicate with biology and bacteria,” he said.
The startup recently closed an £8.5 million ($10.74 million) seed round, according to information obtained exclusively by TechCrunch. The round was led by Exantia Capital with participation from Elbow Beach Capital, Empirical Ventures, Engie New Ventures, Hitachi Ventures, and WEPA Ventures.
Wase plans to roll out a pilot system on dairy farms in Wales this spring. The company also partners with two breweries.
Wase's approach has the potential to reduce the carbon footprint of the entire wastewater treatment process, but the company has not yet done a full accounting. For now, the methane the system produces is combusted on-site, a prudent move because it limits the distance the gas can travel. Research shows that methane leaks along the way are a significant source of greenhouse gases, so supplying natural gas to the grid would make the climate benefits a little less clear.
Still, methane is likely to be transported in some way. The EU has set a target of 35 billion cubic meters of biogas by 2030, meaning this young startup holds great promise regardless of how the biogas is used.