Removing Microplastics from Water: PolyGone's Revolutionary Solution

Dive into the world of microplastic pollution and innovative solutions with PolyGone Systems CEO Nathaniel Banks. In this insightful interview from the CTRL+Listen podcast by Octopart, Banks reveals how his company has developed a groundbreaking passive filtration system that's already removed over 520 million microplastic particles from wastewater. Learn how this Princeton-based clean-tech startup is making water treatment more affordable and accessible worldwide.

Discover the science behind PolyGone's hydrophobic silicon technology that passively attracts microplastics without requiring electricity or pumps, making it ideal for both industrial applications and remote water bodies. Banks also discusses the concerning health implications of microplastics, which can carry toxic additives into human tissue and are now found in drinking water, food, and even human bodies.

Resources from this episode:

• Learn more about PolyGone Systems: https://www.polygonesystems.com/
• Connect with Nathaniel: https://www.linkedin.com/in/nathaniel-banks-954240141/

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Transcript

James: Hi everyone, this is James from the CTRL+Listen Podcast, brought to you by Octopart. Today we have a special guest for you, Nathaniel Banks, CEO of a very interesting company called PolyGone Systems. Thank you for taking the time.

Nathaniel: Thanks very much.

James: Welcome to the show. To start off, do you want to tell people a little about the company, the journey so far, and what it's aiming to do?

Nathaniel: Of course. PolyGone Systems is a cleantech startup based just outside Princeton. Our goal is to develop the first-ever affordable, scalable solutions for microplastics, which are contaminants broadly affecting a lot of the world’s water supplies and ecosystems. I can go a bit into how I got into that if you’d like.

James: Yeah, that’s great. I’d love to hear that.

Nathaniel: My background is actually in design, so nothing directly related to microplastics at first. I worked on very large infrastructural projects, such as the Supertrees in Singapore and sponge city designs in Asia and Europe. But I pivoted my research into dealing with the less talked-about and less “beautiful” parts of infrastructure: waste infrastructure, sewage systems, and waste management systems.

These are critical for cities to function, but you don’t hear much about them, and in many places there isn’t much innovation compared to the more visible parts of cities. As I started looking into waste as part of my university research, it pivoted into microplastics. At the time, four or five years ago, people knew there were a lot of microplastics out there, but there wasn’t much technology being developed to deal with them.

So that became my focus: what systems exist, how effective are they at getting rid of microplastics, and how can we innovate those technologies to be more effective? That was the inception of the research. To achieve that, I partnered across disciplines with people in chemistry, engineering, and environmental science to co-develop the core of our current technology.

James: For anyone who doesn’t know what microplastics are, because that word’s being thrown around a lot lately, could you explain what they are and what that means?

Nathaniel: Sure. This is something people still debate. There are different definitions, but generally microplastics are any plastic pieces, particles, fragments, fibers, or films smaller than 5 millimeters in size, all the way down to the nanometer scale.

They can vary dramatically. Some are visible, around a few millimeters in size, but many are completely invisible. The vast majority are invisible to the naked eye.

They’re a growing concern for two main reasons. First is pervasiveness: they’re everywhere now. We’re finding record levels of microplastics in every ocean, almost every lake and river, in drinking water, wastewater, aquatic seafood, and now even inside human bodies.

Second is potential harm. A lot of research is now asking: are they harmful, what do they contain, and how might they affect human health?

James: Interesting. You mentioned before we started recording that there’s been a definite increase in public awareness. Do you think that’s due to additional research, or is this something we’ve only recently realized is a serious concern?

Nathaniel: I think it’s a combination. When I started researching microplastics, people were vaguely aware, but many had no idea what they were. Now, almost everyone I talk to, even outside my sector, knows the term.

Part of that is the name. “Microplastics” is very clear. Compare that to contaminants like PFAS: if you say there’s PFAS in the water, people who know will worry, but the general public might not know what that means. With microplastics, everyone knows what plastic is. If you say there are microplastics in your water, people immediately picture plastic and get concerned.

Alongside that, there’s been an explosion of research worldwide to determine how much microplastic is in our water, where it’s going, and how harmful it is. The data is starting to give more clarity, especially on health.

What we’re seeing is that the plastic pieces themselves often act as vectors for chemical additives they contain. It’s hard to quantify how harmful a single microplastic is, because there are many types of plastic and additives. Some might be relatively inert, but many contain colorants, flame retardants, plasticizers, and other additives. Many of those are toxic, neurotoxic, endocrine-disrupting, or possibly carcinogenic.

We’re now seeing increased concentrations of microplastics in bodily tissues, correlating with increased intake, and they can act as a vector for these toxic chemicals, which then leach into tissues. That’s where a lot of the concern lies.

James: And one more question on the health side: does the body have any way of breaking these down, or once they enter your body, are they just there forever?

Nathaniel: Plastics are valued because they’re durable. We engineered them not to biodegrade easily; we don’t want them degrading in most applications. For disposable plastics we can now design biodegradable options, but many plastic applications are intentionally long-lasting—boat hulls, components, household products.

When these materials enter your body, they behave similarly. Smaller ones, especially nanoplastics, can get coated in lipids and other bodily compounds that allow them to move through the body more easily. They can move out of the digestive system and into areas like the testicles, brain, bloodstream, and even breast milk.

Once deposited, there’s very little the body can do to break them down quickly, because they’re designed to be robust.

James: Wow. Good to know, but also not great to know. Definitely something to think about. So on your side, what is your product? What does it do exactly, and how does it help with this issue?

Nathaniel: I’ll start with the origin and where we are now. We’re trying to develop an affordable filter system to remove microplastics from a variety of water sources: water treatment facilities, stormwater, reservoirs, coastal systems—most aquatic environments.

The core of our tech is something we co-developed with a chemistry PhD from Princeton. We developed a modified silicon material as the core of our filter. It’s ultra-hydrophobic, so it wants to minimize contact with water.

Most plastics are also hydrophobic. So if you put our hydrophobic silicon and microplastics in water together, they passively want to stick to each other to reduce contact with water. Using this mechanism, we can build filters from this material, place them in water, and any small plastic that passes by will stick to the filter—no electricity, no pumps.

That makes installation and production much easier and cheaper. You don’t need heavy infrastructure, pumps, or high energy usage. The filter passively collects microplastics.

From there, we’ve been designing systems that use this medium in different ways. Our first system is for wastewater: large arrays of this filter media go into the water, are removed and cleaned, we recover the microplastics, and then reuse the filters.

We’re also developing a cartridge system—a plug-and-play solution. It’s a filter cartridge that can go into a piping system, filter out microplastics, and then be swapped and replaced at end of life.

James: Since it doesn’t require pump technology or electricity, is it something you could use in remote locations—say a lake that’s highly polluted with microplastics? Could you just set up a system directly in that body of water?

Nathaniel: That was actually our initial idea. Before applying it in water treatment infrastructure, we wanted to test it in wide, open, remote locations.

Our first test was on an experimental lake in Canada that’s highly contaminated with microplastics—billions of particles dumped into it every couple of weeks for three years. We put a small pontoon device with our silicon filter media on it and just left it in the lake to see what would happen with no forced flow.

We collected hundreds of thousands of microplastics in just a few hours. So we saw it can work at a remote level. And because there are no pumps or strong suction, it avoids harming aquatic wildlife.

One of our current R&D projects, in addition to the cartridges and pods, is a remote USV, a small unmanned surface vehicle that can screen the top of reservoirs and remove surface and near-surface microplastics using our filter.

James: Wow. And those could all be working in tandem potentially, right?

Nathaniel: Exactly. A lot of our R&D focuses on ensuring the systems we develop can interoperate. You don’t need a completely different system for each environment; it’s the same tech, applied slightly differently. That’s easier for us and for users, especially as we build an ecosystem of products.

James: And I imagine that gives you a lot of potential for scalability; you can apply it to many different situations.

Nathaniel: Definitely. From a scaling perspective, timing is important. There’s huge public interest—no one wants microplastics in their water—and the awareness is there. The question is how we translate that into scalable deployments so we have the impact we want.

On the municipal side, there’s interest, but that’s more long-term. Municipalities are driven by regulations: if they’re required to remove microplastics, they’ll pay for it; if not, they’re tight on budgets and hesitant to adopt new tech.

So we’re focusing more near-term on private entities: stormwater companies, reservoir managers, port authorities, and large textile producers. They have public pressure: “What are you doing about microplastics?” Customers are demanding action, which drives adoption on the private side. That’s where we see a lot of near-term opportunity.

James: That leads into the next question: what’s being done currently? Before your technology, what did we have as options?

Nathaniel: For reservoirs, lakes, and rivers, there wasn’t much specific to microplastics. Traditional waste removal uses trash trappers—devices that collect large debris. They’re not designed for microplastics; those are too small.

You could use very fine nets, but that restricts water flow and wildlife movement. Our system is more open and passive, so we can capture smaller microplastics without blocking wildlife pathways.

In water treatment plants, there are technologies like ultrafiltration, reverse osmosis, and granular activated carbon filters that can capture microplastics effectively. The problem is that they are very energy- and infrastructure-intensive. You need big pumps, a lot of electricity, and major capital investment to install these systems.

If you’re an underfunded water authority, you’d have to spend millions to add full-scale microplastic removal. Our goal isn’t to replace those advanced systems, but to fill the gap for facilities that can’t afford or justify them. We provide a more affordable solution that can still remove a significant fraction of microplastics.

James: Do you have any ongoing projects with results you can talk about?

Nathaniel: Yes. We launched the world’s first targeted microplastic removal pilot in Atlantic City at the Atlantic County Utilities Authority. That was our first pilot and it went live last September.

We designed the system over about six months and installed it in around two weeks. It’s been operating since mid-September. We built arrays of filters that go into the water, can be removed, cleaned, and reinserted.

We measure microplastics before and after our system—what’s going into it and what’s coming out—and we also measure how much the filters themselves collect.

We’ve removed around 520 million microplastics from that single effluent stream so far, which is more than we expected. However, the percentage reduction in the effluent concentration wasn’t as high as we wanted. Our goal was over 90% removal; we were seeing closer to 10–15%.

The filters themselves were very effective initially but saturated quickly. We were cleaning them once a week, because it was a manual process, and found they were saturating within a day. After that first day, efficacy dropped sharply.

So now, in phase two of the pilot, we’re automating the system. We’re turning it into a compact unit that automatically introduces, cleans, and reinserts filters multiple times a day. With three or four cleanings a day, we expect much higher overall removal percentages.

The data from this phase—coming later this year—will be key to understanding how much we can reduce microplastics in effluent, not just how many particles we can catch.

James: You mentioned it’s on a stream. Where exactly are the filters placed—top, bottom, outflow?

Nathaniel: This is at a wastewater treatment facility. They have an inflow and outflow. We place our system at the outflow, after their existing treatment processes.

We don’t want to interfere with their current filtration; we want to capture what gets past it. So we measured the effluent first to confirm microplastics were present—which they were—then installed our filters there.

Interestingly, we discovered we’d probably underestimated the microplastic load when we sampled. Treatment plants draw from many sources—homes, industry, etc.—and the mix changes daily. Some days there may be much more microplastic, depending on the source. Our filters revealed much higher volumes than our initial grab samples suggested.

James: Fascinating. Looking ahead, what’s the long-term vision for the company and the next steps?

Nathaniel: Now that our initial pilot has validated that we can remove significant quantities of microplastics, the next step is to validate the high-percentage reduction and full automation. Once that’s done, we essentially have a commercially ready product.

Our goals are:

1. Secure additional pilot locations to test efficacy in different environments.

2. Test and refine the plug-and-play cartridge system.

At the same time, we’re opening our seed round to scale the team. We already have three or four projects agreed and several more in negotiation. To deliver these on a good timeline, we need to build more of our systems in a semi-automated or fully standardized way.

That means setting up a manufacturing facility to assemble devices, load them with media, and ship them at scale. For that, we need more space and a larger team.

James: Have you seen any broader trends in water purification or treatment that are worth paying attention to, even outside microplastics?

Nathaniel: Absolutely. Among emerging contaminants, PFAS is probably the top concern right now. There’s also a lot of focus on pharmaceuticals in water.

In terms of regulation and treatment, there’s a pattern: first you need strong evidence a contaminant is harmful, and second you need viable technology to address it. You can’t regulate something if there’s no way to treat it.

For PFAS, regulators identified them as extremely toxic and set very strict limits—down to four parts per trillion in some cases. To meet that, you need very intense treatment systems, which are expensive and complex. That put a lot of pressure on water systems: they had to scramble to find technology and budget, and the lead times were long.

We expect microplastics to follow as one of the next regulated contaminants, after PFAS and pharmaceuticals. Our aim is to be ready with an affordable, easily scalable solution so there isn’t that same scramble and burden when regulations arrive.

We do that by using standardized components, keeping the media low-energy and low-infrastructure, and designing systems that ideally can be installed in a day, needing only a hose connection and a single power outlet to operate.

James: This might be a bit of an out-there question, but have you looked into water treatment in the developing world and how your tech might fit there?

Nathaniel: We’ve started to. It’s very interesting and very complex.

Take China, for example, which has some of the highest risks and a lot of research activity around microplastics. Their treatment systems are very polarized: either very basic or extremely advanced with state-of-the-art ultrafiltration and reverse osmosis.

Our tech sits in the middle, so in many cases we’re either too advanced for minimal systems or redundant in facilities that already have ultrafiltration.

The U.S. is a different case. It’s an advanced economy, but much of its infrastructure is old—secondary treatment plants from the 1970s that haven’t been fully modernized. They do a decent job but still let contaminants through. That makes the U.S. a very good fit for our technology. Parts of Europe are similar—some highly advanced, some not, and some in-between where we can help.

We’re also starting to look at regions in Africa, Asia, and South America. But water-treatment markets are highly varied in infrastructure, funding, and governance, so it’s complex to evaluate and enter. We do see opportunities, but we need to approach them carefully and with good local understanding.

James: In the U.S., is that mostly a state-by-state issue?

Nathaniel: On the municipal side, yes. Municipal drinking water and wastewater systems are often funded through state revolving funds—SRFs. Those funds support upgrades and maintenance.

If we were to target municipal authorities, we’d likely integrate into those SRFs as microplastics become a priority, offering an affordable solution they can adopt as part of their normal upgrade cycles.

But near-term, more growth will likely come from private entities—stormwater operators, industrial sites, textile makers—because they feel both regulatory pressure and consumer pressure and can move faster than large public utilities.

James: AI is a hot topic right now. Does it play any role in your business?

Nathaniel: At the moment, not much in the core hardware, but it will in the future.

Right now, our main challenge is: can we build effective filtration media and systems to remove microplastics? The analysis we do is heavily lab-based. To accurately measure microplastics, you need to remove organic material, then run precise imaging or spectroscopy. In situ sensors for microplastics are still very unreliable. You can get huge errors if you rely on them today.

We’re automating the lab workflow where we can, but it’s still lab work.

Where AI becomes powerful is on the data side. Our media can be cleaned and the captured microplastics separated. We can then analyze and catalog the type and amount of microplastics collected, and their probable sources.

That data is valuable. If you’re a textile producer, we might show you: “From your process water, we’re capturing X million particles, mostly of this polymer and additive combination.” That can inform how you change your processes and materials to reduce emissions—preventing microplastics from entering the water in the first place.

As we aggregate data from many deployments, we can build AI models to understand patterns: where microplastics are coming from, how they move, how concentrations vary, and how policy or process changes affect them.

So AI will be important for analytics and system-level understanding, rather than for the basic filtration hardware in the short term.

James: You raised a really interesting point about what happens to the microplastics you remove. What does happen to them?

Nathaniel: We’re probably one of the only companies collecting real-world microplastics from wastewater at scale, so there’s no established “microplastic waste industry” yet. We’re helping define what responsible handling looks like.

When we clean our filters, we end up with a concentrated mixture of water and microplastics—lots of fibers and particles.

Recycling is difficult. These plastics are degraded by UV and erosion, often mixed types, and contaminated. Conventional recycling doesn’t work well.

One option is pyrolysis—high-temperature thermal destruction, similar to what’s used for PFAS. That can destroy the plastics but requires lots of energy and can emit CO₂ and other compounds. It’s a last-resort option.

We’re exploring enzymatic conversion: using enzymes that digest certain plastics and convert them into useful chemicals, like carotene as an industrial feedstock. This is promising but slow and often specific to certain plastics. Mixed waste is harder.

We’re also exploring using microplastics as additives—for example, incorporating them into concrete, which can slightly improve strength and effectively lock the plastics away in a long-lived material. That’s containment rather than destruction but is still useful.

There’s no perfect solution yet, so we’re working with research partners on multiple pathways. It may end up being a combination—some fraction enzymatically converted, some locked into materials, some destroyed if necessary.

James: I imagine sorting is a big piece of that—separating plastics into categories?

Nathaniel: Potentially, yes. We’re still early in that phase. As we start collecting larger volumes, sorting will become more relevant.

Typical sorting methods use density separation, but some plastics have similar densities. Other separation methods are more complex. Sorting microplastics is its own scientific challenge.

Ideally, we’d like solutions that don’t require perfect sorting—processes that can handle mixed plastics. That’s where some of the enzymatic work and additive applications are promising, because they can potentially handle mixed streams.

There’s a lot to figure out, and we’re prioritizing: first, remove microplastics effectively; second, develop responsible, scalable end-of-life solutions.

James: Thank you so much for taking the time today. It’s been a fascinating discussion. I’m sure a lot of people are coming away with questions and maybe some new concerns about something they hadn’t thought much about before.

Nathaniel: Thanks. We don’t want to scare people—we want to provide solutions. If anyone is worried about microplastics in their water, we do offer an analysis service. But our main focus is building filters to actually remove these particles from water systems.

If anyone is interested in working with us or learning more, we’re very happy to connect.

James: If someone does want to reach out, what’s the best way to contact you?

Nathaniel: Through our website. We have contact forms there, and you can also order test kits if you want to test your water. The site explains our technology and has our main contact email and forms to reach our team.

James: And on social media, what’s the best place to follow along with updates and new products?

Nathaniel: We’re on LinkedIn, Instagram, and X, all under “PolyGone Systems.”

James: Fantastic. Again, thank you so much. The awareness alone is valuable, and like you said, it’s still a very fresh topic for the public, so there’s going to be a lot of research and development coming. Can’t wait to see what happens next.