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    Unleashing capacity at Heineken México with systems thinking from MIT

    It’s no secret that a manufacturer’s ability to maintain and ideally increase production capability is the basis for long-run competitive success. But discovering a way to significantly increase production without buying a single piece of new equipment — that may strike you as a bit more surprising. 

    Global beer manufacturer Heineken is the second-largest brewer in the world. Founded in 1864, the company owns over 160 breweries in more than 70 countries and sells more than 8.5 million barrels of its beer brands in the United States alone. In addition to its sustained earnings, the company has demonstrated significant social and environmental responsibility, making it a globally admired brand. Now, thanks to a pair of MIT Sloan Executive Education alumni, the the firm has applied data-driven developments and AI augmentation to its operations, helping it solve a considerable production bottleneck that unleashed hidden capacity in the form of millions of cases of beer at its plant in México.

    Little’s Law, big payoffs

    Federico Crespo, CEO of fast-growing industrial tech company, and Miguel Aguilera, supply chain digital transformation and innovation manager at Heineken México, first met at the MIT Sloan Executive Education program Implementing Industry 4.0: Leading Change in Manufacturing and Operations. During this short course led by John Carrier, senior lecturer in the System Dynamics Group at MIT Sloan, Crespo and Aguilera acquired the tools they needed to spark a significant improvement process at Mexico’s largest brewery.

    Ultimately, they would use Valiot’s AI-powered technology to optimize the scheduling process in the presence of unpredictable events, drastically increasing the brewery throughput and improving worker experience. But it all started with a proper diagnosis of the problem using Little’s Law.

    Often referred to as the First Law of Operations, Little’s Law is named for John D.C. Little, a professor post tenure at MIT Sloan and an MIT Institute Professor Emeritus. Little proved that the three most important properties of any system — throughput, lead time, and work-in-process — must obey the following simple relationship:

    Little’s law formula says work-in-progress is equal to throughput multiplied by lead time.

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    Little’s Law is particularly useful for detecting and quantifying the presence of bottlenecks and lost throughput in any system. And it is one of the key frameworks taught in Carrier’s Implementing Industry 4.0 course.

    Crespo and Aguilera applied Little’s Law and worked backward through the entire production process, examining cycle times to assess wait times and identify the biggest bottlenecks in the brewery.

    Specifically, they discovered a significant bottleneck at the filtration stage. As beer moved from maturation and filtration to bright beer tanks (BBT), it was often held up waiting to be routed to the bottling and canning lines, due to various upsets and interruptions throughout the facility as well as real-time demand-based production updates.

    This would typically initiate a manual, time-intensive rescheduling process. Operators had to track down handwritten production logs to figure out the current state of the bottling lines and inventory the supply by manually entering the information into a set of spreadsheets stored on a local computer. Each time a line was down, a couple hours were lost.

    With the deficiency identified, the facility quickly took action to solve it.

    Bottlenecks introduce habits, which evolve into culture

    Once bottlenecks have been identified, the next logical step is to remove them. However, this can be particularly challenging, as persistent bottlenecks change the way the people work within the system, becoming part of worker identity and the reward system.

    “Culture can act to reject any technological advance, no matter how beneficial this technology may be to the overall system,” says Carrier. “But culture can also provide a powerful mechanism for change and serve as a problem-solving device.”

    The best approach to introducing a new technology, advises Carrier, is to find early projects that reduce human struggle, which inevitably leads to overall improvements in productivity, reliability, and safety.

    Heineken México’s digital transformation

    Working with Federico and his team at, and with full support of Sergio Rodriguez, vice president of manufacturing at Heineken México, Aguilera and the Monterrey brewery team began connecting the enterprise resource plan and in-floor sensors to digitize the brewing process. Valiot’s data monitors assured a complete data quality interaction with the application. Fed by real-time data, machine learning was applied for filtering and the BBT process to optimize the daily-optimized production schedule. As a result, BBT and filtration time were reduced in each cycle. Brewing capacity also increased significantly per month. The return on the investment was clear within the first month of implementation.

    The migration to digital has enabled Heineken México to have a real-time visualization of the bottling lines and filtering conditions in each batch. With AI constantly monitoring and learning from ongoing production, the technology automatically optimizes efficiency every step of the way. And, using the real-time visualization tools, human operators in the factory can now make adjustments on the fly without slowing down or stopping production. On top of that, the operators can do their jobs from home effectively, which has had significant benefits given the Covid-19 pandemic.

    The key practical aspects

    The Valoit team was required to be present on the floor with the operators to decode what they were doing, and the algorithm had to be constantly tested against performance. According to Sergio Rodriguez Garza, vice president supply chain for Heineken México, success was ultimately based on the fact that Valiot’s approach was impacting the profit and loss, not simply counting the number of use cases implemented.

    “The people who make the algorithms do not always know where the value in the facility is,” says Garza. “For this reason, it is important to create a bridge between the areas in charge of digitization and the areas in charge of the process. This process is not yet systematic; each plant has a different bottleneck, and each needs its own diagnosis. However, the process of diagnosis is systematic, and each plant manager is responsible for his/her own plant’s diagnosis of the bottleneck.”

    “A unique diagnosis is the key,” adds Carrier, “and a quality diagnosis is based on a fundamental understanding of systems thinking.” More

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    Using mechanics for cleaner membranes

    Filtration membranes are critical to a wide variety of industries around the world. Made of materials as varied as cellulose, graphene, and nylon, they serve as the barriers that turn seawater into drinking water, separate and process milk and dairy products, and pull contaminants from wastewater. They serve as an essential technology to these and other industries but are plagued with an Achilles heel: fouling.

    Membrane fouling occurs when particles get deposited on the filter over time, clogging the system and limiting its effectiveness and efficiency. Efforts to clean, or de-foul, these membranes have typically relied on chemical processes, in which synthetic solvents are pumped through the membrane to flush the system. However, this results in losses in productivity and profit, all while raising environmental and workplace safety concerns associated with waste disposal.

    A solution to this challenge may soon be in sight. A team of researchers from the MIT Department of Mechanical Engineering, supported by a seed grant from MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), has found an alternative. Their solution was developed via a unique collaboration between researchers with expertise in fluid as well as structure dynamics.

    The team has developed a novel system that can mechanically clean membranes using controlled deformation. Their new approach, one of the first ever to combine membranes and mechanics, has the potential to be cheaper, faster, and more environmentally friendly than traditional membrane cleaning techniques, and is poised to revolutionize the way we think about filtration.

    “Fouling is the biggest problem that’s facing membranes. Being able to solve it would be a game-changer for everyone,” says Omar Labban PhD ’20 of the Department of Mechanical Engineering, a joint lead author of a new paper published in the Journal of Membrane Science.

    Controlling the pressure on either side of this membrane allows the layer of contaminants to peel off and wash away.

    Image courtesy of the researchers

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    The work got its start when two mechanical engineering professors saw the potential of uniting their areas of expertise. John Lienhard, the Abdul Latif Jameel Professor of Water and Mechanical Engineering and the director of J-WAFS, joined forces with Xuanhe Zhao, Professor of Mechanical Engineering and George N. Hatsopoulos Faculty Fellow. Lienhard is an international expert on water purification and desalination, while Zhao specializes in the field of soft materials.

    “Real-world problems, such as membrane fouling, inherently cut across disciplinary lines,” says Lienhard. “In this case, we faced both a problem of soft matter mechanics and of membrane desalination. Our team combined this disparate knowledge through a solid experimental program to achieve a more environmentally benign cleaning process.”

    The paper that details the team’s new approach was selected as an Editor’s Choice Article by the journal for February 2021. Paper co-authors Lienhard, Zhao, and Labban were also joined by co-lead author and member of the core research team driving this work, Grace Goon PhD ’20 of the Department of Aeronautics and Astronautics, and Zi Hao Foo, a former visiting student and current graduate student in mechanical engineering.

    The “Achilles heel” of filtration

    Fouling is the process through which particles are deposited on a membrane’s surface. While it occurs in any membrane filtration system, fouling is especially troublesome for desalination. As a process input, seawater has much more than salt that needs to be removed. Foulants, ranging from bacteria to organic material and minerals, can collect on reverse osmosis membranes very quickly. Once membranes become clogged, they are less effective, limiting the amount of clean water that can be produced as well as the purity of the end product.

    Unfortunately, the current cleaning solution is not ideal. Membranes used for desalination are cleaned with chemicals, which takes time, money, and resources away from filtration plant operation. Water desalination plant operators often have to stop production to flush their systems for several hours per cleaning cycle. For the dairy industry, operators need to clean the membranes multiples times a day. The chemical cocktails used to flush the systems are often proprietary, making desalination prohibitively expensive for some countries and municipalities. The environmental impact is also hefty because the plants then must figure out how to dispose of the large quantities of chemical waste without causing ecological and toxicological problems.

    Working together for a cleaner solution

    Motivated by efficiency, affordability, and environmental sustainability, the research team sought to develop a chemical-free solution enabled by the principles of mechanics. Goon, a member of the core research team, recounts the early days, when the team explored various vibration methods, including a stereo system, to shake the foulant layer off the membrane. From there, they moved on to experimenting with varying the pressure on either side of the membrane to weaken the bonded debris. Eventually, they were able to cause the layer to peel off.

    Their solution relies on a phenomenon known as membrane-foulant interfacial fatigue. Through subtle pressure changes, the team was able to gradually weaken and deform the bonded layer of foulants little by little until it could be washed away. Previous research strayed away from this method because of the fragility of the membranes, “but we’ve shown that if you’re able to actually control it properly, you can avoid damaging your membrane,” says Goon. Best of all, the method can be used on the industry-standard spiral wound membrane module, where the tightly spaced layers of membranes posed a challenge for other mechanical cleaning methods.

    While traditional chemical cleaning processes might be necessary to supplement this mechanical solution, this new method can reduce users’ reliance on chemical flushing, which benefits plant operators in multiple ways. The team’s calculations indicate that the shutdown time for cleaning would go down by a factor of six. With plants down less often, the total amount of clean water produced by the system can increase. “You’ll be saving on cost, you’ll be running the plant more, you’ll be getting more output. When cleaning no longer becomes a burden for the operator, the system is going to operate in a much better state in the long run,” explains Labban.

    These improvements provide tangible benefits to producers and consumers alike. During field research the team explored the market potential for this technology and spoke with plant operators across a number of industries who all expressed frustration with the cumbersome nature of the cleaning process. For the dairy industry alone, one that has already faced shrinking profits from the pandemic, the team estimates that a switch to mechanical cleaning could cut cleaning costs by half.

    The unique intersection of membrane technology and mechanical processes that this technology models provides a solution that many in the desalination field did not think was possible. “Suddenly you’re able to achieve a lot a lot more than before — your impact and change that you can accomplish becomes bigger,” says Labban of the chance to work on a multidisciplinary collaboration.

    The project not only brought together two specialties in the Department of Mechanical Engineering and the Department of Aeronautics and Astronautics. The team was also joined by Gabrielle Enns, Annetoinette Figueroa, Lara Ketonen, Hannah Mahaffey, Bryan T. Padilla, and Maisha Prome through MIT’s Undergraduate Research Opportunity Program. The unique perspective that each team member brought helped foster creativity and camaraderie around the lab.

    Because of the out-of-the-box approach that the interdisciplinary research team was taking, traditional funding mechanisms were not as readily available for this work. This is why the J-WAFS seed grant was so impactful. “Without J-WAFS, this work would not have happened,” says Labban. The grant allowed the research team to focus on the challenge as a primary research catalyst, as opposed to being limited to a particular technical process or structured outcome. This provided the team the freedom to take advantage of the cross-departmental collaboration that enabled the convergence of mechanics and membrane research in the name of better filtration strategies.

    The current paper primarily looks at organic foulants and the technique has only been evaluated for a limited number of industries. Looking forward, however, the team is excited to expand upon its research by applying the method across a variety of areas, including the energy and agriculture sectors. As long as membranes are being used, there is going to be a need to clean them. “We are excited to be solving the major bottleneck with membranes and desalination,” says Labban. “Nothing else compares to this challenge.” More

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    Innovations in water accessibility

    Growing up in coastal Connecticut, Flora Klise’s childhood was shaped by water. She spent summers taking sailing lessons and working at a local marina. But it wasn’t until she stood next to a well in rural Tanzania that she realized she wanted to pursue a career in water innovation.

    The summer before her junior year, Klise traveled to Tanzania alongside a team of MIT D-Lab students to work on the Okoa Project, an ambulance trailer that can be attached to motorcycles. While visiting one particular rural village, she noticed dozens of young children carrying large buckets and taking turns jumping up and down on a pump to get water from the well. At the kids’ urging, Klise started pumping water herself.

    After five exhausting minutes pumping water, Klise rethought her career aspirations.

    “It got me really thinking about water accessibility from an engineer’s perspective, and how the way people get water is so different in every part of the world,” says Klise, currently a senior studying mechanical engineering. “There’s a whole area of innovation in water accessibility — from filtering bacteria and viruses to figuring out how to get water to a house or rigging a device that makes pumping easier.”

    Up until that point, Klise had focused on medical devices throughout her undergraduate experience at MIT. Concerned that it was too late to pivot from a career path in medical devices to one in water research, she sought the advice of her advisor, Warren Seering, the Weber-Shaughness Professor of Mechanical Engineering.

    Seering encouraged Klise to follow her passion and not feel boxed in by her previous academic focus.

    “Professor Seering asked, ‘Are you having fun exploring water research?’ and I said ‘Yes.’ To which he then said ‘See, you’re doing it right. You’re doing a great job,’” adds Klise. “Everyone needs an advisor who encourages them like that.”

    In addition to a supportive advisor, Klise found freedom in the flexibility a mechanical engineering degree provides.

    “Mechanical engineering is an area where you can get the technical skills you need to be able to do pretty much whatever you want,” she says. “You’re not limited by anything because it’s so broad, so it gives you the freedom to choose what you are actually passionate about, even later on in your undergraduate experience.”

    With a renewed focus on water accessibility, Klise sought a UROP (Undergraduate Research Opportunities Program) project on water research. She quickly found an opportunity in the lab of John Lienhard, professor of mechanical engineering. Her project was to focus on desalinating brackish groundwater for agricultural use.

    As a relative novice to water research, Klise had some catching up to do. Yvana Ahdab SM ’17, PhD ’21, a research assistant in the Lienhard lab, provided Klise with relevant literature to help her fill in the gaps.

    “Working with Flora was seamless. She possesses the intellectual curiosity and drive central to the scientific research process, which often involves a series of setbacks before any success is realized,” says Ahdab.

    Together, they worked on testing monovalent selective electrodialysis for the treatment of brackish groundwater. This process only filters harmful ions, keeping the ions that promote plant growth in the water. As a result, farmers save money by not needing to add as much fertilizer to their water, offering them a cost-effective, sustainable desalination alternative.

    “The target application is to use this in agricultural irrigation systems. We’ve developed a cost model demonstrating the amount of money saved by not using as much fertilizer,” says Klise.

    Last spring, before campus shut down due to the pandemic, Klise spent most of her time in the wet lab testing the flow rate of their system. After leaving campus due to lockdown, her focus shifted to a new project developing a techno-economic model for the pretreatment of groundwater. This project turned into Klise’s senior thesis.

    Using a database of 28,000 brackish groundwater samples from the U.S. Geological Survey, Klise has been writing a MATLAB script to demonstrate how much money could be saved by pretreating groundwater with lime.

    Klise has also pursued her passion for water research outside the lab. In the mechanical engineering and D-Lab class 2.729/EC.729 (Design for Scale), she worked on the FairCap project to develop a device that could filter a bucket of water, rather than individual glasses. Last fall, she worked as a student researcher for MIT Sea Grant, helping develop an autonomous aquaculture robot for oyster farming. As a member of MIT Water, Klise was active in planning Water Night 2021, held on April 22.

    “Water Club is an amazing community at MIT of people passionate about water issues. Water Night is a real celebration of water that’s engaging for all ages,” she says.

    After graduating in June, Klise will be joining one of the largest water innovation companies in the world, Xylem. Through Xylem’s two-year Engineering Leadership Development Program, Klise will rotate between three different positions across the company to get a sampling of different areas of water innovation she can pursue throughout her career.

    “My main career motivation is the impact of water research and technology. Every year, the need for fresh accessible water is increasing, so there is really a need for innovation in that area,” says Klise.

    While only a fraction of MIT students may end up pursuing careers in water innovation, according to Klise water is something that affects everyone on campus, whether they realize it or not.

    “I think every student at MIT is connected to water and the ocean just from living in Cambridge or Boston. It’s inevitable that you are going to see things, smell things, and notice things related to water. I think that helps people rethink their relationship with water and how it impacts their own lives,” she adds. More

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    Top collegiate inventors awarded 2021 Lemelson-MIT Student Prize

    Following a year that demonstrated the importance and practical applications of scientific advancement and invention, the Lemelson-MIT Program announced seven winners of its annual 2021 Lemelson-MIT Student Prize on April 26, World Intellectual Property Day. The program awarded a total of $90,000 to four graduate students and three undergraduate teams from across the country. The majority of winners have filed for patents, while others have been awarded full or provisional patents. Their inventions range from an innovative approach to plastic pollution in Uganda to self-driving wheelchair technology.

    “We are thrilled with and inspired by the quality of inventions this year,” says Michael J. Cima, faculty director of the Lemelson-MIT Program and associate dean of innovation at the MIT School of Engineering. “This group of students has performed tremendous work amidst difficult circumstances, often working remotely, knowing their research is too important to slow down. Science and technology have been at the forefront of conversation over the past year, and this diverse group of students is well-positioned to lead us toward great advances for years to come,” Cima says.

    Supported by The Lemelson Foundation and administered by the School of Engineering, the Lemelson-MIT Student Prize recognizes and provides catalyst funding to young inventors who have dedicated themselves to providing scalable solutions to real-world problems around the globe. This year’s winners have invented solutions that address pregnancy-related complications, market losses in the agricultural industry, obstacles impeding smooth patient recoveries, and other pressing problems in society. Recipients were selected from a diverse and highly competitive pool of hundreds of applicants from colleges and universities across the United States. 

    “Congratulations to this year’s winners for their remarkable achievements and dedication to solving some of the biggest challenges facing society today,” says Carol Dahl, executive director of the Lemelson Foundation. “It’s particularly exciting to see this year’s cohort of graduate winners is all women, given the fact that a large gender disparity exists in patenting. More inventors are needed from communities historically underrepresented in invention, including women, if we are going to effectively solve the challenges of today and tomorrow.”

    2021 Lemelson-MIT Student Prize winners were selected based on the overall inventiveness of their work, the invention’s potential for scalable commercialization or adoption, and youth mentorship experience. They are:

    The “Cure it!” Lemelson-MIT Student Prize: Rewarding technology-based inventions that involve health care.

    •    Nicole Black of Harvard University, $15,000 Graduate Winner The eardrum often becomes damaged through traumatic head injuries, blast injuries, chronic ear infections, and other incidents, affecting millions of people worldwide every year. Current eardrum graft materials are tissues taken from other parts of the body. These current grafts intend to repair damage, yet do not integrate well with the eardrum and surrounding tissue, resulting in poor healing and hearing outcomes that often require further surgery. Using novel biodegradable materials and 3D printing techniques, Black invented a tunable, biomimetic eardrum graft called PhonoGraft. Because PhonoGraft is able to retain the circular and radial structure of the eardrum, its sound-induced motion is similar to that of original eardrum tissue. Additionally, PhonoGraft acts as a kind of scaffolding that bridges the hole and becomes part of the native tissue, allowing the eardrum to essentially heal itself and restore hearing more effectively.

    •    Mira Moufarrej of Stanford University, $15,000 Graduate WinnerPregnancy-related complications like preeclampsia and preterm delivery pose significant risks to both fetal and maternal health and are often difficult to detect in time for effective medical intervention. Moufarrej developed three novel liquid biopsy tests that monitor prenatal health and identify high-risk pregnancies by more accurately predicting due date, risk of preeclampsia, and likelihood of preterm delivery, making assessments possible well in advance of the mother becoming symptomatic. Following preclinical validation, these affordable, simple, and reliable maternal blood tests may change the standard of care for preeclampsia and preterm delivery — risks that no other test can currently predict early enough to allow for meaningful clinical intervention.

    •    Innerva: Bruce Enzmann, Michael Lan, and Anson Zhou of Johns Hopkins University, $10,000 Undergraduate Team WinnerTargeted muscle reinnervation (TMR), a procedure to connect severed nerves to smaller motor nerves, is an increasingly popular method for treating peripheral nerve injuries, as it partially guides nerve regeneration and makes it possible for amputees to more effectively operate prosthetic devices. About 30 percent of TMR patients, however, experience pain due to nerve tumors, or neuromas, that result from the inherent differences in size between the newly connected nerves. Innerva’s invention is a nerve conduit that creates an interface between the different sized nerves connected during TMR, modulating nerve regeneration and preventing the formation of neuromas.

    The “Eat it!” Lemelson-MIT Student Prize: Rewarding technology-based inventions that involve food/water and agriculture.

    •    Hilary Johnson of MIT, $15,000 Graduate WinnerCentrifugal pumps are integral drivers in many fluid systems, such as clean water distribution, wastewater treatment, crop irrigation, oil and gas production, and pumped hydro energy storage. Requiring significant energy to operate, collectively these pumps consume 6 percent of annual U.S. electricity. Hilary’s invention is a variable volute pump, a new category of centrifugal pumps that mechanically adapts the hydraulic chamber to adjust to fluctuating system demand. Variable volute pumps show the potential to significantly improve efficiency and operating range across applications by adjusting the spiral fluid passages to match the flow rate.

    •    Grain Weevil: Benjamin Johnson and Zane Zents of the University of Nebraska at Omaha, $10,000 Undergraduate Team WinnerLarge grain bins are used to store surplus grain supplies and allow farmers to hold their yield for higher prices. Managing grain condition and extraction require farmers to physically enter the grain bin, which is difficult and dangerous, often trapping and even killing farmers. A lack of proper management and extraction systems cause a 30 percent loss in cereal grain value worldwide. The Grain Weevil is a grain extraction and bin management robot that scurries across the top of the grain within a bin, smoothing out clumps so that the grain can be properly aerated and easily extracted from the bin. This device helps farmers safely and efficiently manage the extraction of grain from the bin, as well as maintain grain quality while in storage.

    The “Move it!” Lemelson-MIT Student Prize: Rewarding technology-based inventions that involve transportation and mobility.

    •    Adventus Robotics: Maya Burhanpurkar and Seung Hwan An of Harvard University, $10,000 Undergraduate Team WinnerPower wheelchairs present formidable barriers to mobility for users unable to operate a joystick, and manual wheelchairs operated by porters within hospitals can increase the potential for disease transmission between patients and staff. To solve these issues, the Adventus team developed a hardware and software kit that can be retrofitted to power wheelchairs already on the market to convert them into Level 5 (fully autonomous) self-driving wheelchairs. Adventus’ system transcends existing assistive technologies by using artificial intelligence and fail-safe sensors for edge detection and collision prevention. In light of Covid-19, the team’s technology has the potential to be used in a variety of other applications like autonomous floor cleaning and disinfecting.

    The “Use it!” Lemelson-MIT Student Prize: Rewarding technology-based inventions that involve consumer devices and products.

    •    Paige Balcom of the University of California at Berkeley, $15,000 Graduate WinnerTakataka Plastics is a technology and systems-level solution for plastic waste in Uganda that locally recycles plastic waste and creates jobs for vulnerable youth. Paige developed small-scale, locally built, low-cost machines to transform plastic waste into saleable products such as wall tiles for buildings, personal protective equipment, and consumer goods. This technology is especially innovative for PET waste because PET plastic (water and soda bottles) currently cannot be recycled anywhere in Uganda, and exporting the waste is difficult and inaccessible to most local recyclers.

    Collegiate inventors interested in applying for the 2022 Lemelson-MIT Student Prize can find more information via the Lemelson-MIT Program. The 2022 Student Prize application will open in late spring 2021. More

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    MIT engineers make filters from tree branches to purify drinking water

    The interiors of nonflowering trees such as pine and ginkgo contain sapwood lined with straw-like conduits known as xylem, which draw water up through a tree’s trunk and branches. Xylem conduits are interconnected via thin membranes that act as natural sieves, filtering out bubbles from water and sap.

    MIT engineers have been investigating sapwood’s natural filtering ability, and have previously fabricated simple filters from peeled cross-sections of sapwood branches, demonstrating that the low-tech design effectively filters bacteria.

    Now, the same team has advanced the technology and shown that it works in real-world situations. They have fabricated new xylem filters that can filter out pathogens such as E. coli and rotavirus in lab tests, and have shown that the filter can remove bacteria from contaminated spring, tap, and groundwater. They also developed simple techniques to extend the filters’ shelf-life, enabling the woody disks to purify water after being stored in a dry form for at least two years.

    The researchers took their techniques to India, where they made xylem filters from native trees and tested the filters with local users. Based on their feedback, the team developed a prototype of a simple filtration system, fitted with replaceable xylem filters that purified water at a rate of one liter per hour.

    Their results, published today in Nature Communications, show that xylem filters have potential for use in community settings to remove bacteria and viruses from contaminated drinking water.

    The researchers are exploring options to make xylem filters available at large scale, particularly in areas where contaminated drinking water is a major cause of disease and death. The team has launched an open-source website, with guidelines for designing and fabricating xylem filters from various tree types. The website is intended to support entrepreneurs, organizations, and leaders to introduce the technology to broader communities, and inspire students to perform their own science experiments with xylem filters.

    “Because the raw materials are widely available and the fabrication processes are simple, one could imagine involving communities in procuring, fabricating, and distributing xylem filters,” says Rohit Karnik, professor of mechanical engineering and associate department head for education at MIT. “For places where the only option has been to drink unfiltered water, we expect xylem filters would improve health, and make water drinkable.”

    Karnik’s study co-authors are lead author Krithika Ramchander and Luda Wang of MIT’s Department of Mechanical Engineering, and Megha Hegde, Anish Antony, Kendra Leith, and Amy Smith of MIT D-Lab.

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    Clearing the way

    In their prior studies of xylem, Karnik and his colleagues found that the woody material’s natural filtering ability also came with some natural limitations. As the wood dried, the branches’ sieve-like membranes began to stick to the walls, reducing the filter’s permeance, or ability to allow water to flow through. The filters also appeared to “self-block” over time, building up woody matter that clogged the conduits.

    Surprisingly, two simple treatments overcame both limitations. By soaking small cross-sections of sapwood in hot water for an hour, then dipping them in ethanol and letting them dry, Ramchander found that the material retained its permeance, efficiently filtering water without clogging up. Its filtering could also be improved by tailoring a filter’s thickness according to its tree type.

    The researchers sliced and treated small cross-sections of white pine from branches around the MIT campus and showed that the resulting filters maintained a permeance comparable to commercial filters, even after being stored for up to two years, significantly extending the filters’ shelf life.

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    The researchers also tested the filters’ ability to remove contaminants such as E. coli and rotavirus — the most common cause of diarrheal disease. The treated filters removed more than 99 percent of both contaminants, a water treatment level that meets the “two-star comprehensive protection” category set by the World Health Organization.

    “We think these filters can reasonably address bacterial contaminants,” Ramchander says. “But there are chemical contaminants like arsenic and fluoride where we don’t know the effect yet,” she notes.


    Encouraged by their results in the lab, the researchers moved to field-test their designs in India, a country that has experienced the highest mortality rate due to water-borne disease in the world, and where safe and reliable drinking water is inaccessible to more than 160 million people.

    Over two years, the engineers, including researchers in the MIT D-Lab, worked in mountain and urban regions, facilitated by local NGOs Himmotthan Society, Shramyog, Peoples Science Institute, and Essmart. They fabricated filters from native pine trees and tested them, along with filters made from ginkgo trees in the U.S., with local drinking water sources. These tests confirmed that the filters effectively removed bacteria found in the local water. The researchers also held interviews, focus groups, and design workshops to understand local communities’ current water practices, and challenges and preferences for water treatment solutions. They also gathered feedback on the design.

    “One of the things that scored very high with people was the fact that this filter is a natural material that everyone recognizes,” Hegde says. “We also found that people in low-income households prefer to pay a smaller amount on a daily basis, versus a larger amount less frequently. That was a barrier to using existing filters, because replacement costs were too much.”

    With information from more than 1,000 potential users across India, they designed a prototype of a simple filtration system, fitted with a receptacle at the top that users can fill with water. The water flows down a 1-meter-long tube, through a xylem filter, and out through a valve-controlled spout. The xylem filter can be swapped out either daily or weekly, depending on a household’s needs.

    The team is exploring ways to produce xylem filters at larger scales, with locally available resources and in a way that would encourage people to practice water purification as part of their daily lives — for instance, by providing replacement filters in affordable, pay-as-you-go packets.

    “Xylem filters are made from inexpensive and abundantly available materials, which could be made available at local shops, where people can buy what they need, without requiring an upfront investment as is typical for other water filter cartridges,” Karnik says. “For now, we’ve shown that xylem filters provide performance that’s realistic.”

    This research was supported, in part, by the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) at MIT and the MIT Tata Center for Technology and Design. More

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    Transforming lives by providing safe drinking water

    As a child, Susan Murcott ’90 SM ’92 saw firsthand the long-term impact that water- and food-borne illness can have on people.

    At age 16, her maternal grandmother contracted polio, which can be transmitted through direct contact with someone infected with the virus or, occasionally, through contaminated food and water. As a result of the illness, she was forever paralyzed from the waist down. Though Murcott didn’t know it at the time, her decades-long career focusing on clean water access would bring her in close collaboration with countless others around the world whose lives, like her grandmother’s, are impacted by unsafe drinking water.

    Murcott is an MIT environmental engineer, social entrepreneur, and educator who has spent her lifetime collaboratively developing and implementing effective, affordable solutions to provide safe water to the world’s neediest.

    “My core work has been focused on water, sanitation, and hygiene,” Murcott says. “It’s not sexy, it’s not a money maker, and it’s not high-profile news even though there are more childhood deaths each year attributable to water-related diseases than to Covid-19.”

    Globally, 2.2 billion people lack safely managed water and 4.2 billion lack basic sanitation. Polluted water is one of the world’s leading causes of disease and death, particularly for children under the age of 5. Furthermore, women and children bear the disproportionate burden of securing household water, limiting their ability to focus on education, employment, and other opportunities for economic and social advancement.

    “I’ve spent 30 years trying to wake people up to the reality of the importance of safe drinking water, both given my family history and travels around the world,” says Murcott. “I feel like it’s still an invisible problem — invisible, at least, to those of us who are privileged enough to take safe water, sanitation, and hygiene for granted.”

    Throughout her time at MIT — as a student, then a senior lecturer in the Department of Civil and Environmental Engineering, and now as a lecturer at MIT D-Lab and a principal investigator driving water solutions innovations through the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) — Murcott has addressed these challenges head-on.

    Murcott’s work started with megacities. Alongside her mentor and colleague, the late MIT civil engineering professor Donald Harleman, she helped to develop and promote innovation in low-energy, low-cost wastewater treatment as an engineering consultant to municipalities in megacities worldwide. Plants in Hong Kong, Rio de Janeiro, and Mexico City have adopted their strategies and are now serving approximately 15.2 million users combined, treating the wastewater instead of dumping raw sewage directly into local waterways.

    A major turning point in Murcott’s career came when she was the keynote speaker and sole female engineer at the Second International Women and Water Conference in Kathmandu, Nepal, in 1998. At that time, 75 percent of Nepali women were illiterate, and many had children sick with water-related diseases. The organizers of that conference, educated women from Kathmandu, invited the entire spectrum of women throughout Nepal to attend. This meant that attendees at the conference included many illiterate women, all the way up to the Queen of Nepal.

    Desperate for solutions to their water problems, the women asked Murcott for help. This encounter proved powerful and career-changing, inspiring her to pivot toward designing and implementing simple, affordable household drinking water systems by working together with these women and vulnerable households, in Nepal and beyond.

    Major success came two year later, when her team of MIT graduate students and partners from the Nepal Department of Water Supply and Sewerage detected the first instances of arsenic in drinking water in Nepal. In collaboration with the Nepali nonprofit Environment and Public Health Organization (ENPHO), over 40,000 tests of arsenic in tubewell groundwater were conducted, tracking the extent of water contamination for the first time.

    “Without Susan and her MIT graduate student team, we wouldn’t have identified the extent of arsenic contamination in Nepal and taken action to implement remediation solutions as quickly as we did,” says Roshan Raj Shrestha, now the deputy director of water, sanitation, and hygiene at the Bill and Melinda Gates Foundation.

    Murcott and ENPHO worked together to design, prototype, pilot, and implement the Arsenic Biosand Filter, subsequently manufactured and distributed throughout 17 arsenic-affected districts of Nepal. She and team members won numerous awards for this, reinvesting award funds in arsenic remediation across the country and training Nepali entrepreneurs to build and market the filters. “Her work has impacted hundreds of thousands of lives, preventing disease and death from arsenic contaminated drinking water. We owe Susan a great deal of gratitude,” says Shrestha.

    Not one to stop at these accomplishments, Murcott then worked to bring her engineering knowledge and entrepreneurial spirit to aid in the elimination of waterborne disease in northern Ghana.

    There, she launched the nonprofit Pure Home WATER to produce ceramic pot water filters that could help eliminate guinea worm from the water supply. Jim Niquette, Ghana country director of the Carter Center Guinea Worm Eradication Campaign, credits these filters for eradicating this debilitating disease from Ghana between 2008 and 2010.

    “We went from 242 cases of guinea worm to zero in 18 months. Prior to what occurred in Ghana, no country had achieved a success of this kind so quickly,” Niquette says. “Susan’s dedication to poor people’s health and well-being, combined with the innovative ceramic pot filter technology, was critical to the unprecedented success.”

    Murcott has since inspired others to build factories, with several of the MIT students she has mentored going on to build and/or manage successful factories in Uganda and South Africa. Overall, she has influenced the construction of ceramic pot filter factories in 10 countries. These factories now provide clean water to approximately 5 million users.

    Murcott continues to improve clean water access in Asia through the creation of the “ECC vial,” an affordable, easy-to-use E. coli test-kit. The project to refine and scale up distribution and use of the ECC vial received support from the MIT Abdul Latif Jameel Water and Food Systems Lab through the J-WAFS Solutions Program sponsored by Community Jameel. Launched in 2020 in partnership with Nepali social entrepreneurs, this novel technology puts water quality measurement in the hands of users. The aim is to enable millions of people in Nepal and across Asia to directly measure the cleanliness of their water and advocate for safe water solutions in the years ahead.

    Murcott’s impact cannot only be measured in the amount of clean water that she has helped provide. Wanting to bring what she saw abroad back to Massachusetts, Murcott was instrumental in the early days of MIT D-Lab, creating its landmark course 11.474 (G) / EC.715

    (D-Lab Water, Sanitation, and Hygiene), which she has taught since 2006. Through this and other courses she has had the opportunity to meet and inspire students early in their careers.

    Driven by her own experience in the male-dominated field of civil engineering, Murcott has committed herself to collaboration and mentorship, with a particular focus on mentoring young women interested in STEM. Her mentees have founded NGOs, launched humanitarian-oriented startups, developed large-scale wastewater infrastructure projects, produced research to influence national policy, and more.

    “She has the unique skill of being able to guide and teach her students while also allowing space for their own curiosity, interests, and ideas,” says Kate Cincotta SM ’09, one of Murcott’s graduate students who went on to co-found the water nonprofit Saha Global. “Susan understands that working in the international development space requires both technical skills and practical knowledge that can only be gained from field experience, and connects her students with the opportunities to gain both.”

    This sense of higher purpose is one that Murcott tries to live out through her research and implementation work inspiring the next generation. “It’s very important, in my life experience, to follow your dream and to serve others. Do something because it’s worth doing and because it changes people’s lives and saves lives.” More

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    Chemists gain new insights into the behavior of water in an influenza virus channel

    In a new study of water dynamics, a team of MIT chemists led by Professor Mei Hong, in collaboration with Associate Professor Adam Willard, has discovered that water in an ion channel is anisotropic, or partially aligned. The researchers’ data, the first of their kind, prove the relation of water dynamics and order to the conduction of protons in an ion channel. The work also provides potential new avenues for the development of antiviral drugs or other treatments.

    Members of the Hong lab conducted sophisticated nuclear magnetic resonance (NMR) experiments to prove the existence of anisotropic water in the proton channel of the influenza M virus, while members of the Willard group carried out independent all-atom molecular dynamics simulations to validate and augment the experimental data. Their study, of which Hong was the senior author, was published in Communications Biology, and was co-authored by Martin Gelenter, Venkata Mandala, and Aurelio Dregni of the Hong Lab, and Michiel Niesen and Dina Sharon of the Willard group.

    Channel water and influenza virus

    The influenza B virus protein BM2 is a protein channel that acidifies the virus, helping it to release its genetic material into infected cells. The water in this channel plays a critical role in helping the influenza virus become infectious, because it facilitates proton conduction inside the channel to cross the lipid membrane.

    Previously, Hong’s lab studied how the amino acid histidine shuttles protons from water into the flu virus, but they hadn’t investigated the water molecules themselves in detail. This new study has provided the missing link in a full understanding of the mixed hydrogen-bonded chain between water and histidine inside the M2 channel. To curb the flu virus protein, the channel would have to be plugged with small molecules — i.e., antiviral drugs — so that the water pathway would be broken.

    In order to align the water-water hydrogen bonds for “proton hopping,” water molecules must be at least partially oriented. However, to experimentally detect the tiny amount of residual alignment of water molecules in a channel, without freezing the sample, is extremely difficult. As a result, the majority of previous studies on the topic were conducted by computational chemists like Willard. Experimental data on this topic were typically restricted to crystal structures obtained at cryogenic temperatures. The Hong lab adopted a relaxation NMR technique that can be employed at the much balmier temperature of around 0 degrees Celsius. At this temperature, the water molecules rotated just slowly enough for the researchers to observe the mobility and residual orientation in the channel for the first time.

    More space, more order

    The evidence yielded by Hong’s NMR experiments indicated that the water molecules in the open state of the BM2 channel are more aligned than they are in the closed state, even though there are many more water molecules in the open state. The researchers detected this residual order by measuring a magnetic property called chemical shift anisotropy for the water protons. The higher water alignment at low pH came as a surprise.

    “This was initially counterintuitive to us,” says Hong. “We know from a lot of previous NMR data that the open channel has more water molecules, so one would think that these water molecules should be more disordered and random in the wider channel. But no, the waters are actually slightly better aligned based on the relaxation NMR data.” Molecular dynamic simulations indicated that this order is induced by the key proton-selective residue, a histidine, which is positively charged at low pH.

    By employing solid-state NMR spectroscopy and molecular dynamics simulations, the researchers also found that water rotated and translated across the channel more rapidly in the low-pH open state than in the high-pH closed state. These results together indicate that the water molecules undergo small-amplitude reorientations to establish the alignment that is necessary for proton hopping.

    Inhibiting proton conduction, blocking the virus

    By using molecular dynamics simulations performed by Willard and his group, the researchers were able to observe that the water network has fewer hydrogen-bonding bottlenecks in the open state than in the closed state. Thus, faster dynamics and higher orientational order of water molecules in the open channel establish the water network structure that is necessary for proton hopping and successful infection on the virus’ part.

    When a flu virus enters a cell, it goes into a small compartment called the endosome. The endosome compartment is acidic, which triggers the protein to open its water-permeated pathway and conduct the protons into the virus. Acidic pH has a high concentration of hydrogen ions, which is what the M2 protein conducts. Without the water molecules relaying the protons, the protons will not reach the histidine, a critical amino acid residue. The histidine is the proton-selective residue, and it rotates in order to shuttle the protons carried by the water molecules. The relay chain between the water molecules and the histidine is therefore responsible for proton conduction through the M2 channel. Therefore, the findings indicated in this research could prove relevant to the development of antiviral drugs and other practical applications. More

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    Startup empowers women to improve access to safe drinking water

    In Ghana’s Northern Region, thousands of villages rely on water from artificial ponds during the region’s long dry season. The water is unsafe to drink and results in thousands of water-borne illnesses each year. Worse yet, the situation is totally preventable.
    Cheap, locally available water treatment solutions exist to make the region’s abundant surface water safely drinkable. The challenge lies in getting families in rural villages to use those solutions exclusively and over the long run.
    Those were the issues Kate Cincotta SM ’09 and Vanessa Green SM ’08, MBA ’11 studied as graduate students at MIT. In order to solve them at scale they created Saha Global, a nonprofit that increases consumption of clean drinking water by empowering local women in each community to start profitable water treatment businesses.
    Saha works with villages to determine a price for clean water that everyone can afford while also fairly compensating the women entrepreneurs for their work. The company then provides training to the women and educates the community about the importance of drinking treated water. Saha also makes a one-time donation of water tanks and buckets to its female entrepreneurs.
    Importantly, Saha continues monitoring water consumption in each village for 10 years after a new business forms, helping entrepreneurs through any challenges they run into. The approach ensures the company maximizes its impact as it scales.
    “We look at things in stages,” Cincotta says. “The first stage is access: opening every business that we can open to get everybody access to clean water. Once that phase is done, the focus is on clean water consumption. How do you get everyone drinking clean water exclusively? If you can achieve that, it’s really just making sure that businesses are making enough money to cover their maintenance costs and are staying open.”
    To date, Saha Global has trained more than 700 women to start businesses in 246 villages. The businesses provide clean drinking water to more than 100,000 people in communities that can’t afford large water treatment plants or modern plumbing systems.
    Saha is also having an impact on the women it partners with, who use the extra income to do things like send their children to school, buy cellphones, and fertilize their farms. The women also become leaders in their communities, gaining confidence as they provide a service that’s of vital importance to everyone around them.
    “This is an opportunity for the women in these settings to showcase their expertise and to give back to their community,” Cincotta says. “I think about times when I personally feel empowered, and it’s when someone looks to me for my expertise or my advice. We can see that happening with these women because this is something they lead in their community.”
    A model for impact
    In 2007, Cincotta enrolled in MIT’s Technology and Policy Program and began working in northern Ghana with Susan Murcott, an environmental engineer, social entrepreneur, and MIT D-Lab lecturer who runs a nonprofit that provides water filters to people in the region. The experience taught Cincotta about barriers to long-term adoption of water treatment technologies in the region’s rural villages.
    “We know how to treat water … and yet at that time, over a billion people still lacked access to safe water,” Cincotta says. “To me, it didn’t seem like a design problem; it was more this interplay between technology and policy and technology and society, and how we get the tech to the people who need it.”
    During a trip to the region in 2008, she met Green, another graduate student working with Murcott to understand consumer preferences around water treatment technologies.
    Cincotta and Green began a research collaboration in the summer of 2008, finding that many Ghanians stopped using their ceramic water filters after they clogged or broke, despite the fact that both problems were easily fixable.
    Still, resolving those issues by monitoring each deployment seemed too time- and labor-intensive for a traditional nonprofit.
    “When you’re a nonprofit or social enterprise trying to distribute a product widely, to maybe a billion people who need clean water, that follow up can get extremely expensive,” Cincotta says.
    To reduce those costs and simplify follow up efforts, the founders decided to invest in one water treatment point in each community. Rather than relying on handouts, the treatment centers would be self-sustaining businesses. The more successful they were, the more clean water would be consumed in the community. And the founders knew just the people to partner with.
    Three women in each village are nominated to build and run each local water treatment business. The women spend about five hours a week on it, and typically earn $1 dollar a week — a significant amount in a region where many families live on less than $2 a day.
    “Most of them know every family in their community and when they’re going to come by and how much water that means they’re going to need to treat that day,” Cincotta says. “They very quickly know way more about running the business and their community than Saha does, and you can see what that does for someone, getting that expertise and using it to serve people they care about.”
    The company’s training shows entrepreneurs how to use the treatment materials, how to fit the water treatment process into their lives, how to announce when water is available, and how to price the water to cover expenses and compensate them for their time. During that period, the company will also go door-to-door in the community to distribute the buckets and educate people on the new business.
    “It all culminates in this big opening day, which is always so exciting,” Cincotta says. “The whole community comes out to get water. It’s also very busy for the entrepreneurs. And it’s basically up and running from there.”
    Saha supports the entrepreneurs with customer care teams that help them through business problems, technicians that train women to repair tanks, and testers who periodically ensure entrepreneurs’ tanks are free of E. coli. The company also continues educating the community on the importance of only drinking clean water.
    “Our goal is always exclusive clean water consumption,” Cincotta says. “We want everyone in every community we work in to drink clean water all the time. We’re not there yet, and so we’re really trying to understand who is coming to buy water frequently and who isn’t, and of the people that aren’t, what are the barriers they’re facing to clean water consumption?”
    Each of Saha’s 246 communities is receiving 10 years of support, and the company will only expand if it can offer the same guarantee to new communities.
    Fulfilling a mission
    Saha started 70 new businesses in 2019, its best year yet. Last year, the Ghanaian government responded to Covid-19 disruptions by mandating that all citizens be provided clean drinking water for free. The government has said it will reimburse Saha’s entrepreneurs for the sales they make, but so far Saha has been forced to fundraise to compensate entrepreurs.
    On the plus side, Cincotta says the company has observed six times more clean water consumption during the pandemic in its communities.
    Saha’s goal is to help everyone in Ghana’s Northern Region who still needs clean water, which amounts to about 800,000 people, by 2025. Cincotta also believes Saha’s model can work anywhere in the world where surface water is abundant.
    “We really see ourselves as part of this bigger goal of universal water access,” Cincotta says, noting Saha’s model works best in villages of 400 to 1,000 people in which water treatment plants may be impractical. “You can’t leave anyone behind, and so you’re really going to need lots of different actors working together. We’re excited about the role we can play in that.” More