High levels of forever chemicals found on wastewater filters

A significant buildup of “forever chemical” concentrations on reverse osmosis filters used in desalination and advanced wastewater treatment highlights the need for proper handling, disposal and recycling.

Texas A&M University

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A reverse osmosis facility featuring hundreds of filters used in water treatment.

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Credit: Dr. Shankar Chellam

As cities across the nation and the globe increasingly turn to advanced water purification systems to expand their drinking water supplies, researchers at Texas A&M University have identified a critical environmental safety consideration. A new study from the Department of Civil and Environmental Engineering shows that per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals,” accumulate significantly on the purification filters used in advanced treatment to recycle wastewater into drinking water.

This breakthrough research examines a real-world potable reuse facility, where municipal wastewater is currently treated to very high standards to produce safe drinking water. Although the technology effectively removes contaminants, the study shows for the first time that microscopic trapping of harmful chemicals causes significant accumulation on the filters over their operational lifespan.

These findings carry implications for public health and environmental policy. When water utilities replace thousands of worn-out filtration membranes, the accumulated PFAS could pose risks to workers handling the equipment or leach into local groundwater if the components are discarded improperly. By detailing exactly how and where these persistent chemicals accumulate, the research provides engineers with the foundational data needed to develop safer disposal protocols and advanced cleaning techniques.

Civil and environmental engineering professor Dr. Shankar Chellam, his post-doctoral fellow Dr. Onkar Ekande, his former Ph.D. student Dr. Bilal Abada, and Brent Alspach, director of applied research at Arcadis, were co-authors of the study, published in the Journal of Membrane Science.

The research team analyzed several commercial reverse osmosis filters — coiled, sheet-like polymer membranes — that had been operating for four consecutive years at a full-scale potable reuse facility. 

“Reverse osmosis is excellent at removing PFAS, just like it’s excellent at removing salts,” said Chellam. “It’s literally a desalination technology, and it is good for removing a lot of contaminants, but it’s expensive.”

Reverse osmosis works by forcing water through a dense, highly selective polymer membrane under high pressure, leaving salts, minerals and contaminants behind. Because wastewater contains much higher levels of PFAS than typical freshwater sources like lakes or rivers, these filters face an intense barrage of chemical pollutants over years of continuous service in a potable reuse plant.

This research addresses a crucial gap by analyzing the concentrations of these chemicals on the filters themselves. The team discovered that long-chain PFAS compounds often bind strongly to organic and biological fouling layers — slimes or biofilms composed of proteins, sugars and microorganisms — that naturally form on filter surfaces over time.

“There could be a correlation between the bio-organic fouling and PFAS accumulation on the filter surfaces,” said Abada. “In all but the very last filtration stage, we found organic fouling.”

The researchers discovered that long-chain, water-repelling PFAS variants accounted for two-thirds of the trapped chemical mass in the initial stages of membranes. Additionally, chemical precursors — compounds that degrade over time into more stable forms of PFAS — accounted for another 14% of the accumulation. In contrast, the final stage of the filtration system, which was dominated by chalky mineral scales rather than organic slime, retained almost no PFAS.

“PFAS is toxic at very low concentrations, and they have been reported in numerous drinking water sources and wastewater,” said Chellam. “The removal technologies currently in use, such as reverse osmosis, take a water stream that is relatively dilute in PFAS and concentrate the toxic chemicals to much higher levels on the filters.”

The conclusions drawn from this study add critical data on a widely concerning pollutant and support policymaking and regulatory oversight. Future research on PFAS mitigation technologies can also benefit from these results in terms of membrane life cycle analysis.

“The problem of membrane use, cleaning and disposal will only become bigger and bigger,” said Abada. “Even if we become more efficient and make the membranes last longer, we still have to figure out how to safely handle and dispose of them once they reach their end of life.”

As water-stressed communities continue to adopt advanced recycling technologies, these insights help ensure they can do so with a better understanding of the impact of PFAS accumulation on membrane lifecycles.

By Justin Agan, Zachry Department of Civil and Environmental Engineering, Texas A&M University

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DOI

10.1016/j.memsci.2026.125425 

Article Title

Accumulation of per- and polyfluoroalkyl substances and their precursors in fouling layers on end-of-life reverse osmosis membranes in a full-scale potable reuse facility

INDENTURED SERVITUDE DESERVES A LIVING WAGE

Long hours, lack of social support undermine caregivers’ well-being, study finds

McGill researchers say spending more than 20 hours a week on caregiving is associated with poorer mental health, and that policymakers should take note

McGill University

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While caregiving can be meaningful and rewarding at manageable levels, those who spend more than 20 hours a week delivering unpaid care to others have poorer mental health outcomes, a McGill study has found.

However, the researchers also found that the provision of social support to high-intensity caregivers mitigates negative impacts.

“Programs that connect intensive caregivers to emotional, informational and practical support (respite care, caregiver support groups, community services) could make a real difference,” said Amélie Quesnel-Vallée, Professor and Chair of the Department of Equity, Ethics and Policy and senior author of the study.

“Policies that focus solely on who is a caregiver miss the point: how much someone is caregiving matters enormously for their well-being,” Quesnel-Vallée said.

“Factors we often assume matter (gender, income, education, where you live) did not significantly change how caregiving affected mental health once intensity was taken into account,” she added.

Long-term data reveal patterns

The team used data from the Canadian Longitudinal Study on Aging (CLSA), a large, nationally representative cohort of over 51,000 Canadians ages 45-85 at baseline. The study followed them over three time points, roughly from 2011 to 2021.

The researchers categorized the participants into four groups (non-caregiver, low, moderate, intensive) and tested whether factors like gender, income, education and social support affected the relationship between the participants’ caregiving activities and their mental health. They also controlled for stable personal characteristics that might otherwise distort results, such as personality or early-life health issues.

“Intensive caregivers (who spent more than 20 hours a week on caregiving) had worse mental health – lower life satisfaction and more depressive symptoms – while low-intensity caregivers (under 10 hours a week) actually reported higher life satisfaction than non-caregivers,” Quesnel-Vallée summarized.

The research also showed that, for high-intensity caregivers, the only factor that buffered against the mental health toll of caregiving was how much social support they reported receiving.

Practical implications

The researchers maintain that, given that more Canadians will take on unpaid caregiving roles in the future due to the country’s aging population, the results have practical implications for policymaking.

For Zilin Li, a postdoctoral researcher in the Consortium on Analytics for Data-Driven Decision-Making and lead author of the study, it’s important that policymakers highlight the positive aspects of caregiving in offering support.

“Policies should invest in strengths-based supports that empower caregivers through training and recognition of their skills and values,” she said.

The researchers said they hope future research can track the caregiving journey and its long-term mental health impacts in more comprehensive ways, identify the types of caregiving support that would be most beneficial and collect data on caregivers under 45, who were not included in the CLSA.

About the study

“Social disparities in associations between informal caregiving intensity and mental health: Evidence from the Canadian Longitudinal Study on Aging”, by Zilin Li, Isabelle Vedel and Amélie Quesnel-Vallée was published in Social Science & Medicine.

This research was supported by the Canadian Institutes of Health Research.

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Journal

Social Science & Medicine

DOI

10.1016/j.socscimed.2026.119188 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Social disparities in associations between informal caregiving intensity and mental health: Evidence from the Canadian Longitudinal Study on Aging

 

Can online reviews replace health inspectors? New study says not so fast

Research finds Yelp reviews reveal some restaurant hygiene problems, but they miss others

Institute for Operations Research and the Management Sciences

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BALTIMORE, June 24, 2026 – Consumers increasingly rely on online reviews to decide where to eat, but can those reviews replace traditional health inspections? New research published in the INFORMS journal Marketing Science suggests the answer is both “yes” and “no.”

The study, “Consumer Reviews and Regulation: Evidence from New York City Restaurants,” finds that online reviews contain meaningful information about certain restaurant hygiene problems, particularly issues customers can directly experience, such as pests, spoiled food and food temperature violations. However, reviews provide little insight into many less visible sanitation and safety issues routinely monitored by health inspectors.

Researchers Chiara Farronato of Harvard Business School and Georgios Zervas of Boston University analyzed millions of Yelp reviews alongside detailed New York City restaurant inspection records. Their findings show that consumers can often identify and communicate visible hygiene problems through online reviews, creating an additional layer of accountability for restaurants.

“Online reviews can provide valuable information about some aspects of restaurant hygiene, but they cannot fully substitute for government inspections,” said Farronato. “Consumers are good at spotting problems they can see, smell or experience directly, but many important safety issues remain invisible to the public.”

Using machine-learning techniques, the researchers identified specific words and phrases in reviews that were associated with future health code violations. Terms related to pests, illness and food contamination, for instance, were among the strongest indicators of hygiene problems that were later documented by inspectors.

The study also found that consumers pay attention to these signals. Restaurants were less likely to sell out after receiving online reviews that contained strong indications of hygiene concerns.

Perhaps most notably, the research suggests that restaurants themselves tend to respond to the scrutiny created by online reviews. Businesses with greater visibility on review platforms tended to have fewer violations in areas where consumers could readily identify problems and discuss them online.

The findings arrive as policymakers, platforms and consumers increasingly debate whether digital reputation systems can serve some of the functions traditionally performed by government regulation.

“Our results suggest that online reviews and regulation work best as complements rather than substitutes,” said Zervas. “Reviews provide frequent, low-cost information that can help consumers and regulators alike, but they are much more effective at detecting some problems than others.”

The authors noted that regulators could potentially use information from online reviews to help target inspections, while restaurants could use review data to identify operational issues before they become serious compliance problems.

Read the review in full here.

About INFORMS and Marketing Science

INFORMS is the world’s largest association for professionals and students in operations research, AI, analytics, data science and related disciplines, serving as a global authority in advancing cutting-edge practices and fostering an interdisciplinary community of innovation. Marketing Science, a leading journal published by INFORMS, publishes research on quantitative marketing, consumer behavior, pricing, and strategy that informs managerial and policy decisions. INFORMS empowers its community to improve organizational performance and drive data-driven decision-making through its journals, conferences and resources. Learn more at www.informs.org or @informs.

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Contact

Rebecca Seel

Public Affairs Specialist

rseel@informs.org

(443) 757-3578

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Journal

Marketing Science

DOI

10.1287/mksc.2023.0088 

Subject of Research

People

Article Title

Consumer Reviews and Regulation: Evidence from New York City Restaurants

 

One plant, three kingdoms, five trips

Weizmann Institute scientists decipher how a well-known psychedelic substance is created, then engineer a plant to produce several psychedelics at once

Weizmann Institute of Science

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Long before scientists began studying them in the lab, mind-altering substances were already being gathered from plants, fungi and even animals for use in rituals, healing practices and mental health treatment. Researchers at the Weizmann Institute of Science have now managed to bring together in a single organism five psychedelic substances that in nature are scattered across the tree of life. After uncovering how plants naturally produce one of the best-known psychedelic compounds, DMT, they were able to reengineer that process step by step inside a model plant – along with four other psychedelics. The result is what amounts to a biological factory that could, in the future, be used to simultaneously produce multiple psychedelic molecules, including some that do not naturally occur in plants.

The study was led by Dr. Paula (Shirley) Berman, who worked at the time in Prof. Asaph Aharoni’s lab in Weizmann’s Plant and Environmental Sciences Department; she is now a principal investigator at the Agricultural Research Organization – Volcani Institute. The findings were recently published in Science Advances.

The five compounds in the study – all well-known psychedelics – come from three different kingdoms of life. The plant kingdom contributed DMT, the brain-active component of ayahuasca, a ceremonial hallucinogenic brew long used in shamanic Amazonian rituals for spiritual healing. The researchers derived DMT from several plant sources, including the leaves of a woody shrub from the coffee family, native to the Amazon rainforest, and the bark of an acacia species native to the Australian outback.

From the kingdom of fungi they took psilocybin and psilocin – the compounds responsible for the effects of “magic mushrooms,” with psilocybin once having been central to Aztec ceremonies. Representing the animal kingdom was the Sonoran Desert toad; it has glands on its head and skin that release a milky defensive secretion when it is stressed. This secretion contains bufotenin, as well as a more potent relative of DMT called 5-MeO-DMT, known to induce distinct psychedelic experiences – a fact well-known by those who have sought out the toad with the express purpose of licking it.

Despite their diverse origins, all five compounds belong to the same chemical family and share the same starting point: tryptophan, a common amino acid found in all living organisms. This is also the starting point the human body uses to produce serotonin, a neurotransmitter involved in regulating mood and well-being. That shared origin helps explain why psychedelics act on the same receptors in the brain as serotonin.

“At the heart of the study was the challenge of making DMT,” explains Aharoni.

Although scientists had previously mapped the general route of DMT production in nature, the exact genes and enzymes responsible were still unknown, and identifying the complete biosynthetic DMT pathway remained elusive. The researchers began by identifying the key genes, particularly those encoding the enzymes that drive each step of the pathway. They then inserted these genes into a model plant – Nicotiana benthamiana, a tobacco relative widely used in research – effectively teaching it to produce DMT. Within days, the engineered plant began generating the compound.

When the scientists produced the other four psychedelics individually in separate tobacco plants, one of them – 5-MeO-DMT – was manufactured in surprisingly low amounts. To address this, the team collaborated with Prof. Sarel Fleishman and Dr. Olga Khersonsky of Weizmann’s Biomolecular Sciences Department, experts in protein design. They identified a subtle problem: a molecule that did not fit well into the active site of one of the enzymes. By changing a single building block – one amino acid – in the enzyme’s structure, they improved the fit.

The result was dramatic. “We mutated one amino acid in the sequence and got a 40-fold increase in the production of 5-MeO-DMT,” Berman says.

The scientists then introduced genes for the five compounds into the same plant. The system worked. A single plant was able to produce all five psychedelics: plant-origin DMT; fungus-origin psilocin and psilocybin; and animal-origin bufotenin and 5-MeO-DMT.

“In effect, we created a kind of biological ‘cocktail’ – not by mixing substances externally, but by combining the underlying pathways inside one organism,” Aharoni says.

At the same time, the experiment revealed an important limitation. When multiple pathways were activated at once, they began to compete for the same starting material. In biological terms, the system reached a bottleneck, and production efficiency dropped.

Finally, the team pushed the system beyond what occurs in nature. By adding bacterial enzymes, they produced modified psychedelic molecules carrying chlorine or bromine atoms in specific positions – something that evolution had apparently left out of the plant’s job description but might prove therapeutically valuable. Several such molecules have already shown intriguing biological activity, including antidepressant-like effects, as part of the growing search for new treatments for disorders such as depression, anxiety, PTSD and addiction.

The research points toward new ways of producing psychedelic compounds. Many are currently obtained from slow-growing plants, rare fungi or animal sources, often raising ecological and ethical concerns. The Sonoran Desert toad, for example, is increasingly threatened by habitat loss and overcollection. Plants used for ayahuasca are also under growing pressure due to land loss and rising demand.

Producing these molecules in fast-growing laboratory plants could provide a more sustainable alternative, reducing the need to harvest vulnerable species while making production more efficient and scalable. Plants are grown, the genes are introduced, and within about a week, measurable amounts of the psychedelic can be extracted. 

More available molecules mean more opportunities for research. One open question is why plants produce these compounds in the first place. Psychedelic molecules did not evolve so humans could “trip,” or to treat anxiety or depression; they likely serve ecological roles, such as defense or interactions with microbes and insects. By engineering plants to produce them in controlled settings, researchers can begin to study these possibilities directly.

“If we can move these pathways into a model plant that grows quickly and is easy to manipulate, we can start asking what these compounds actually do for the plant,” Berman explains. Researchers can examine how they affect the plant’s defenses or whether they influence its growth or stress responses.

The scientists are now also exploring the possibility of engineering a plant that produces the full ayahuasca mixture. In traditional preparations, DMT is combined with another compound that allows the brew to be active when swallowed. In the Amazon, this is achieved by mixing leaves containing DMT with twigs bearing another substance that facilitates DMT’s absorption from the digestive tract. Scientists now aim to create a single plant that would contain both components.

Yet another potential direction involves producing therapeutic psychedelics in edible plants, so the substances could be consumed in carefully regulated doses.

All in all, the Weizmann study is not only about psychedelic compounds. It points to a broader shift in the relationship between plant biology and drug development – one in which plants are no longer just sources of rare molecules, but living platforms for studying, reshaping and potentially producing the next generation of psychiatric treatments.

Also taking part in the study were Janka Höfer, Herschel Mehlman, Efrat Almekias-Siegl, Dr. Sagit Meir and Dr. Ilana Rogachev of Weizmann’s Plant and Environmental Sciences Department; Dr. Let Kho Hao of Weizmann’s Plant and Environmental Sciences Department and the Agricultural Research Organization – Volcani Institute; Drs. Yonghui Dong, Uwe Heinig and Yoav Peleg of Weizmann’s Life Sciences Core Facilities Department; Dr. Shahar Cohen from the Agricultural Research Organization – Volcani Institute; and Dr. Liron Sulimani and Prof. David Meiri from the Technion – Israel Institute of Technology.

Prof. Asaph Aharoni’s research is supported by Marc & Joëlle Melviez-Zysman; the Sklare Family Plant Growth Facility Fund; Monica Rosenzweig Armour; Magnus Konow in honour of his mother Olga Konow Rappaport; the Harry and Jeanette Weinberg Plant Molecular Genetics Research Center; the Knell Family Institute for Artificial Intelligence; the Melvyn A. Dobrin Center for Nutrition and Plant Research; the Charles W. and Tillie K. Lubin Center for Plant Biotechnology; and the Tom and Sondra Rykoff Fund for Plant, Environmental, and Sustainability Research.

Prof. Aharoni is the incumbent of the Peter J. Cohn Professorial Chair.

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Journal

Science Advances

DOI

10.1126/sciadv.aeb3034 

 

New framework identifies freshwater conservation priorities

International Institute for Applied Systems Analysis

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Freshwater ecosystems are under growing pressure worldwide, but conservation resources are limited. A framework developed by IIASA researchers and partners can help identify where conservation could prevent biodiversity loss and where restoration efforts are likely to have the greatest ecological impact across the United States and Europe.

Freshwater biodiversity is declining faster than biodiversity in terrestrial or marine ecosystems. Yet conservation efforts often lack practical tools to identify where action is most urgently needed.

Stream fish communities offer critical insights into the condition of freshwater habitats. As landscapes are modified for agriculture, urban development, and other human uses, stream fishes respond in predictable ways. However, these responses are not always gradual. Rather than declining steadily, fish communities often reach "tipping points" where environmental pressures exceed a critical threshold, leading to substantial shifts in species composition and abundance. Once these thresholds are crossed, ecological conditions can deteriorate rapidly and become much harder to restore.

In a study published in npj Biodiversity, researchers have developed a new framework that applies the current understanding of these ecological thresholds to guide conservation and restoration decisions across the United States and Europe. The framework enables conservation practitioners to identify where proactive measures can prevent ecosystem decline and where restoration efforts should be prioritized to achieve the greatest impact. By identifying where fish communities are most vulnerable to crossing known thresholds, the study provides resource managers and spatial planners with a practical, policy-relevant tool for optimizing land-use decisions.

"One of the biggest challenges in freshwater conservation is the lack of comparable data across large geographic regions," explains Kyle Brumm, a research scholar in the Biodiversity, Ecology, and Conservation Research Group of the IIASA Biodiversity and Natural Resources Program. "By combining ecological thresholds with information on existing protected areas, we identify where proactive conservation and restoration actions are needed to prevent future declines and support the recovery of freshwater ecosystems."

Rather than simply mapping biodiversity or human pressures, the framework identifies where ecosystems are approaching ecological tipping points.

"Stream fish communities integrate the effects of multiple environmental pressures across entire river catchments," says coauthor Dana Infante, Professor at Michigan State University in the United States. "That makes them powerful indicators of ecosystem conditions. Linking these biological responses to ecological thresholds helps identify where freshwater ecosystems are most vulnerable, before declines become more difficult and costly to manage."

A practical tool for resource allocation

The newly developed framework integrates ecological thresholds with protected area coverage to assess how upstream pressures affect downstream fish communities. By distinguishing between areas where decline can still be prevented and those that may ultimately require restoration, the framework helps target limited resources more effectively:

• Conservation priorities: Catchments with limited formal protection that are close to crossing ecological thresholds.
• Restoration priorities: Catchments that have already crossed ecological thresholds despite having a high degree of protection.

This distinction is particularly important because preventing ecosystem degradation is often far more cost-effective and ecologically effective than restoring ecosystems after they have already been degraded.

Consistent applications across diverse regions

By applying the framework to regions with contrasting land-use histories and regulatory contexts across both continents, the study demonstrates that threshold-based approaches can be used consistently over broad geographic extents. Despite major differences in land-use history, governance, and conservation policies between Europe and the United States, the framework performed consistently across both regions.

The findings reveal a broad gradient of ecological condition across more than 1.7 million stream reaches. While some remain relatively intact, many are experiencing multiple environmental pressures that increase their risk of crossing ecological thresholds.

More broadly, the research highlights that protected area coverage alone is not always sufficient to maintain freshwater biodiversity. In some catchments, ecological thresholds have been exceeded despite substantial protection, underscoring the need to complement protected area designations with targeted restoration and management.

"Freshwater restoration is fundamentally a spatial planning challenge," says coauthor Rafaela Schinegger, Associate Professor for Nature Conservation Planning at BOKU University in Vienna, Austria. "This framework helps identify where conservation can prevent ecological tipping points and where restoration measures will have the greatest ecological benefit. Such evidence-based approaches are essential for prioritizing actions and supporting the effective implementation of the EU Nature Restoration Regulation."

The authors note that while the framework was developed and tested across the United States and Europe, the underlying approach could be applied more broadly wherever ecological threshold information is available.

As pressures on freshwater ecosystems continue to increase worldwide, conservation resources need to be invested where they can achieve the greatest impact. Threshold-based planning provides a practical way to identify these priorities before rapid ecological change occurs and could serve as a valuable model for freshwater conservation planning in other parts of the world.

Reference
Brumm, K.J., Schinegger, R., Schürz, M., Gruber, G., Borgwardt, F., Seliger, C., & Infante, D.M. (2026). Applying ecological thresholds to inform conservation and restoration efforts for stream fishes. npj Biodiversity DOI: 10.1038/s44185-026-00144-7 [pure.iiasa.ac.at/21681]

About IIASA:

The International Institute for Applied Systems Analysis (IIASA) is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policymakers to shape the future of our changing world. IIASA is independent and funded by prestigious research funding agencies in Africa, the Americas, Asia, and Europe. www.iiasa.ac.at

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Journal

npj Biodiversity

DOI

10.1038/s44185-026-00144-7 

Article Title

Applying ecological thresholds to inform conservation and restoration efforts for stream fishes

 

New autonomous monitor prevents drone crashes in real time

University of Houston engineer develops safety system to protect drones from sudden hazards

University of Houston

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Marzia Cescon, David C. Zimmerman Assistant Professor of Mechanical & Aerospace Engineering at the University of Houston Cullen College of Engineering, calls her new system a "safety supervisor," as it will keep drones out of harm's way.

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Credit: University of Houston

Key Takeaways: 

• A University of Houston engineer developed a real-time safety system that helps quadrotor drones avoid crashes. 

• The new technology can prevent accidents caused by unexpected events like a gust of wind or anything that pushes the drone off course. 

• The research moves advanced drone safety technology forward. 

A University of Houston engineer has built a new safety monitor system for the operation of quadrotor drones that can keep them on course and out of danger in real time. 

Typically, a drone follows directions of its pilot or onboard software, but if there is an unexpected occurrence, like a gust of wind, the drone can be thrown off course and head for danger. That’s when this new system would step in, enabling the drone to stay within safety limits to complete its task.  

The quadrotor (or quadcopter), the most popular type of drone, is powered by four rotors, is extremely agile and can hover with precision. Because it’s easy to fly, and fits nicely into tight spaces, it is popularly used in everything from structural inspections to photography. 

Marzia Cescon, David C. Zimmerman Assistant Professor of Mechanical & Aerospace Engineering at the UH Cullen College of Engineering, calls her new system a "safety supervisor." She announced the system in the American Society of Mechanical Engineers Digital Collection. 

The safety supervisor is actually a new module onboard the drone. Cescon created it to guarantee run-time assurance, a safety mechanism that continuously watches the system while it is flying. To keep the drone safe, the module monitors the drone’s tilt and position in real time. 

“You can think of it as an invisible fence that defines where the drone can safely be. Whenever the ‘safety supervisor’ predicts that the drone will get dangerously close to the fence and potentially crash onto it, the algorithm we designed pushes it away from it,” said Cescon, who developed and tested the supervisor algorithm in the UH Advanced Learning, Artificial Intelligence and Control laboratory. 

Technically, the supervisor is implemented as a Control Barrier Function, that is a mathematical tool used to decide if the drone is approaching danger, and if so, takes control of the flight to keep things safe.   

"This work advances the state of the art by showing how CBF-based RTA schemes can be reliably integrated with standard optimal controllers and deployed on real hardware, highlighting practical tradeoffs between various implementations. The work fills an important gap between CBF and RTA theory and deployable real-world control systems,” said Cescon. 

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Journal

Journal of Dynamic Systems Measurement and Control

Article Title

A Run-Time Assurance Approach for Safe Control of a Quadrotor

Article Publication Date

1-Sep-2026

Marzia Cescon, David C. Zimmerman Assistant Professor of Mechanical & Aerospace Engineering at the University of Houston, flying drones in her lab. [VIDEO] 

Marzia Cescon, David C. Zimmerman Assistant Professor of Mechanical & Aerospace Engineering at the University of Houston, has created a safety net for drones thrown off course. 

Credit

University of Houston