How Princeton grads are removing microplastics in wastewater

Sept. 1, 2023
Princeton University grads Nathaniel Banks and Yidian Liu have developed a removal technology to address microplastics in wastewater from synthetic clothing fibers to single-use plastic bottles among other sources.

It is easy to grasp the harmful impact of discarded plastic that ends up as litter on the roadway or in the ocean. But what about the effects of smaller, less visible plastics that stealthily slip into our environment?

The sources of microplastics in wastewater

Microplastics, or tiny plastic particles that come from a variety of sources, are becoming a growing environmental concern. They include plastic particles that break off as larger items degrade as well as microbeads used in beauty products. Another source? Fibers that break off clothing made with synthetic materials often used to create inexpensive fast fashion.

Although often undetectable to the naked eye, microplastics can easily accumulate and have been found in both the stomachs of marine animals and the blood stream of human beings.

While research on microplastics is ongoing, the impact of chemicals used to make plastics have been widely studied, and the results are not good. Chemicals used to make plastic have been shown to disrupt reproductive, growth and liver functions in marine life.

Despite this growing concern, there seems to be no simple way to turn off the flow of microplastics.

A microplastics solution for wastewater

After learning about the prevalence of microplastics, Princeton University grads Nathaniel Banks and Yidian Liu were moved to solve the issue. Using their backgrounds in architecture and product design, they assembled a team to develop an effective way to capture microplastics before they enter the environment.

“Both Nathaniel and I were shocked to learn that, while large plastic pollutants are actively collected and recycled from waterways, little to no systems exist to capture or recycle the trillions of potentially harmful microplastics entering the world's oceans and drinking water each year,” Liu said. “We knew we needed to do something about this problem.”

Banks and Liu have since created a product with their New Jersey based startup, PolyGone, which is a filtering system that can be installed at wastewater treatment facilities to remove microplastics from effluent.

The product has gone through several iterations and was awarded a $1.9 million grant from Marine Debris Challenge Award from National Oceanic and Atmospheric Administration (NOAA), to improve and implement the technology.

ACUA wastewater plant partners with PolyGone developers

Recognizing that wastewater treatment plants are the last form of defense for many harmful contaminants, the PolyGone team began seeking a partner treatment facility willing to implement a pilot project. The team did not have to go far to find a partner with the same concern for the environment and forward-thinking approach.

The Atlantic County Utilities Authority (ACUA) based in Atlantic City, New Jersey, welcomed the team and its proposed project. The local environmental authority is no stranger to innovation. It is the first coastal wastewater treatment facility in the country to harness wind energy to power its facility. The plant also runs on solar power and is home to a renewable energy storage battery and a soon-to-be hydrogen project.

“One of ACUA’s greatest attributes as an environmental leader is its willingness to explore new ideas and research,” said ACUA President Matthew DeNafo. “We welcomed the opportunity to collaborate with PolyGone on this pilot program and do what we can to minimize the harmful effects of microplastics.”

ACUA’s coastal wastewater treatment facility serves 14 municipalities. The authority owns more than 60 miles of pipeline and 19 pump stations located throughout Atlantic County that transport wastewater from homes and businesses to the facility. The facility can treat up to 40 million gallons of wastewater per day, but normally treats an average of 29 million gallons per day. Its effluent is released into the Atlantic Ocean, and its biosolids are currently incinerated.

As mentioned, the treatment process is powered through renewable energy generated on-site by the Jersey-Atlantic Wind Farm, which includes five 1.5-megawatt wind turbines, as well as 2,700 solar panels. A state-certified water testing laboratory is also on-site and ensures the facility is meeting all environmental quality standards.

How PolyGone removes microplastics from wastewater

PolyGone and ACUA have collaborated on a design that will fit into the existing treatment system without causing disruption. PolyGone’s floating filter mimics a natural wetland to capture microplastics as water passes through. It will be installed in ACUA’s equalization basin, which is the last stop before treated wastewater is sent out to the Atlantic Ocean.

As the filters fill up with microplastic debris, they will be discarded. The microplastics collected from the filters will be collected and ultimately taken to a recycling facility.

To track the success of the project, water samples will be collected and analyzed to measure microplastic debris. The coconut fiber brushes will be extracted, collected, and analyzed in a lab for their microplastic count. Looking through a microscope, a tough, rigid, and crystalline thermoplastic fiber would be visible in the coconut fiber sample, which would indicate that the brush successfully captured microplastics from the stream.

The pilot with ACUA will allow PolyGone to further refine its technology. It will be the first of its kind and, if successful, can be replicated at other treatment facilities.

Educating the public on microplastics pollution

ACUA’s established reach in the community was another reason PolyGone was happy to partner with the Authority. The utility regularly welcomes thousands of visitors each year to its facility for tours to inform the community about its operations.

“Even though wastewater treatment plays an essential role in our daily lives, most people do not even think twice about it when they run the dishwasher at home or flush the toilet,” said DeNafo. “We continually work to change that by inviting the public to our facility and through outreach to schools and community organizations.”

In addition to helping solve the problem, PolyGone and ACUA will work to educate the community about the technology and the dangers of microplastics by installing an educational pavilion next to the project at the facility. The educational pavilion will allow visitors to witness the pilot in real time and see how it works.

Wastewater industry revolution

This pilot showcases the potential that the wastewater industry must grow and evolve with changing public health concerns. During the covid pandemic, for example, many scientists were working with wastewater treatment facilities to source new information about the impact and spread of disease. It was one of the few times that the hidden power of wastewater was brought to the attention of the public.

This microplastics pilot project showcases yet another opportunity for the wastewater industry to embrace partnerships and align itself with innovation. It shows that this often forgotten about essential service can play an even bigger role in achieving a cleaner environment throughout the future.

“This pilot project will bring more attention to the important role wastewater treatment plays in creating clean and healthy communities,” DeNafo said.

The pilot program and educational pavilion is expected to be operational in 2024.

About the Author

Ryan Mahoney | communications assistant for ACUA

Ryan Mahoney is communications assistant for Atlantic County Utilities Authority.

About the Author

Sara Verrillo | chief customer relationship manager for ACUA

Sara Verrillo is chief customer relationship manager for Atlantic County Utilities Authority.