Manufacturing A Cleaner Future (“MIT MECHE”)


Published on November 29, 2022

Source: MIT MECHE

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Manufacturing had a big summer. The CHIPS and Science Act, signed into law in August, represents a massive investment in US domestic manufacturing. The Act aims to drastically expand the US semiconductor industry, strengthensupply chains, and invest in R&D for new technological breakthroughs. According to John Hart, professor of mechanical engineering and director of the Laboratory for Manufacturing and Productivity at MIT, the CHIPS Act is just the latest example of significantly increased interest in manufacturing in recent years.

 

“You have multiple forces working together: reflections from the pandemic’s impact on supply chains, the geopolitical situation around the world, and the urgency and importance of sustainability,”says Hart. “This has now aligned incentives among government, industry, and the investment community to accelerate innovation in manufacturing and industrial technology.”

 

Hand in hand with this increased focus on manufacturing is a need to prioritize sustainability.

 

Roughly one-quarter of greenhouse gas emissions came from industry and manufacturing in 2020. Factories and plants can also deplete local water reserves and generate vast amounts of waste, some of which can be toxic.

 

To address these issues and drive the transition to a low-carbon economy, new products and industrial processes must be developed alongside sustainable manufacturing technologies. Hart sees mechanical engineers as playing a crucial role in this transition.

 

“Mechanical engineers can uniquely solve critical problems that require next generation hardware technologies, and know how to bring their solutions to scale,” says Hart.

 

Several fast-growing companies founded by faculty and alumni from MIT’s Department of Mechanical Engineering offer solutions for manufacturing’ environmental problem, paving the path for a more sustainable future.

 

Gradiant: Cleantech water solutions

 

Manufacturing requires water, and lots of it. A medium-sized semiconductor fabrication plant uses upwards of 10 million gallons of water a day. In a world increasingly plagued by droughts, this dependence on water poses a major challenge.

 

Gradiant offers a solution to this water problem. Co-founded by Anurag Bajpayee SM ’08 PhD ’12 and Prakash Govindan PhD ’12, the company is a pioneer in sustainable – or “cleantech” – water projects.

 

As doctoral students in the Rohsenow Kendall Heat Transfer Laboratory, Bajpayee and Govindan shared a pragmatism and penchant for action. They both worked on desalination research – Bajpayee with Professor Gang Chen and Govindan with Professor John Lienhard.

 

Inspired by a childhood spent during a severe drought in Chennai, India, Govindan developed a humidification dehumidification technology that mimicked natural rainfall cycles for his PhD. It was with this piece of technology, which they named Carrier Gas Extraction (CGE), that the duo founded Gradiant in 2013.

 

The key to CGE lies in a proprietary algorithm that accounts for variability in the quality and quantity in wastewater feed. At the heart of the algorithm is a non-dimensional number, which Govindan proposes one day be called the “Lienhard Number,” after his doctoral advisor.

 

“When the water quality varies in the system, our technology automatically sends a signal to motors within the plant to adjust the flow rates to bring back the non-dimensional number to a value of one. Once it’s brought back to a value of one, you’re running in optimal condition,” explains Govindan, who serves as COO of Gradiant.

 

This system can treat and clean the wastewater produced by a manufacturing plant for reuse, ultimately conserving millions of gallons of water each year.

 

As the company has grown, the Gradiant team has added new technologies to their arsenal, including Selective Contaminant Extraction, a cost-efficient method that removes only specific contaminants, and a brine-concentration method called Counter-Flow Reverse Osmosis. They now offer a full technology stack of water and wastewater treatment solutions to clients in industries including pharmaceuticals, energy, mining, food and beverage, and the ever-growing semiconductor industry.

 

“We are an end-to-end water solutions provider. We have a portfolio of proprietary technologies and will pick and choose from our ‘quiver’ depending on a customer’s needs,” says Bajpayee, who serves as CEO of Gradiant. “Customers look at us as their water partner. We can take care of their water problem end-to-end so they can focus on their core business.”

 

Gradiant has seen explosive growth over the past decade. With 450 water and wastewater treatment plants built to date, they treat the equivalent of 5 million households’ worth of water each day. Recent acquisitions saw their total employees rise to above 500.

 

The diversity of Gradiant’s solutions is reflected in their clients, who include Pfizer, AB InBev, and Coca-Cola. They also count semiconductor giants like Micron Technology, GlobalFoundries, and TSMC among their customers.

 

“Over the last few years, we have really developed our capabilities and reputation serving semiconductor wastewater and semiconductor ultra-pure water,” says Bajpayee.

 

Semiconductor manufacturers require ultra-pure water for fabrication. Unlike drinking water, which has a total dissolved solids range in the parts per million, water used to manufacture microchips has a range in the parts per billion or quadrillion.

 

Currently, the average recycling rate at semiconductor fabrication plants – or fabs – in Singapore is only 43%. Using Gradiant’s technologies, these fabs can recycle 98-to-99% of the 10 million gallons of water they require daily. This reused water is pure enough to be put back into the manufacturing process.

 

“What we’ve done is eliminated the discharge of this contaminated water and nearly eliminated the dependence of the semiconductor fab on the public water supply,” adds Bajpayee.

 

With new regulations being introduced, pressure is increasing for fabs to improve their water use, making sustainability even more important to brand owners and their stakeholders.

 

As the domestic semiconductor industry expands in light of the CHIPS and Science Act, Gradiant sees an opportunity to bring their semiconductor water treatment technologies to more factories in the US.