Vikram Kumar: Seeking Sustainable Answers for Waste Residue

Vikram Kumar: Seeking Sustainable Answers for Waste Residue

Vikram Kumar was always a bright student in elementary and high school, but he felt constrained by the lack of creativity he could engage in when doing schoolwork. Wanting instead to confront questions with undetermined answers, Kumar naturally gravitated toward research — which eventually led him to the Rapid AI-based Dissection of Ashes using Raman and XRF Spectroscopy (RADAR-X) Project.

“Everything had a correct answer in high school courses, and I did not have any responsibility to make things correct. I did not enjoy that,” Kumar said. “Research is the only place I can be responsible for answering questions that do not have an answer yet.”

Kumar began his pursuit of the unknown at the Indian Institute of Technology (BHU) Varanasi, where he received a bachelor’s degree in civil engineering. In spring 2020, he enrolled at the University of Illinois Urbana-Champaign for his master’s degree in civil engineering, and now he’s working on his Ph.D. in civil and environmental engineering with a specialization in construction materials.

“I came to UIUC for its top-ranked Civil and Environmental Engineering (CEE) program, and also for its tranquility,” Kumar said. “These components give UIUC an atmosphere that is unlike anywhere else in the world.”

Magnified ash residue.

Kumar is on the operating team for the RADAR-X Project, which finds end uses for municipal solid waste incineration ashes — residues left over from the incineration of trash. However, because researchers have no control over what is in the trash, the ashes can be extremely variable, and different types of ash lend themselves to different uses. So, the first step of RADAR-X is to understand the chemical characteristics of these residues. Then, researchers can identify specific end uses for each chemical composition, purify the ashes, and get to work on implementation.

End uses vary widely. For example, if the ash residue happens to have a high content of heavy metals or rare earth elements, such as aluminum, copper, iron, gallium, and dysprosium, those elements can be extracted and utilized, instead of being mined anew. Another example is cement production, an industry responsible for approximately eight percent of global carbon dioxide emissions. Ashes may be integrated into cement mix, decreasing the need for raw materials.

The primary limiting factor in implementing ash end uses more conventionally is the variable composition of the ashes. Therefore, from a waste-to-energy facility’s standpoint, it is imperative that these ashes qualify for multiple end uses. The suitability of an ash for a specific use is dependent on its chemical composition. So, guidelines to determine end use from chemical composition must first be established. RADAR-X is addressing this hurdle by developing real-time characterization capabilities: spectroscopy-based analytical methods that will enable incineration facilities to determine ash’s chemical composition continuously every few minutes. In addition to RADAR-X’s objective to determine chemical composition in real time, the project will establish chemical composition-specific end use guidelines, benefitting waste-to-energy facilities in diverting ashes from landfills to industries that can employ the ashes as components for applications like cement.

In his day-to-day research, Kumar spends copious time in the lab. The RADAR-X team primarily does its work at the Nathan M. Newmark Civil Engineering Laboratory on campus, and team members receive ashes from approximately 40 different incineration facilities throughout the U.S.

“My role is to understand the chemical characteristics of incineration ashes via spectroscopic methods,” Kumar said. “Then, I design pretreatment methods that make an ash of a specific chemical composition fit for multiple end uses.”

The spectroscopic methods RADAR-X uses to discover ashes’ elemental and mineralogical composition are X-ray fluorescence and raman spectroscopy, which identifies a sample’s elemental composition by using X-rays. When subjected to X-rays, elements respond by emitting photons in characteristic radiations. The concentration of a given element is directly related to the intensity of the characteristic radiation. By analyzing the emitted characteristic radiation, researchers determine the composition and concentration of elements present in the ash.

iSEE initially seed-funded CEE Assistant Professor Nishant Garg and the RADAR-X project in 2020. In 2021, Garg’s team received a $1 million grant from the Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E), allowing the project to expand its scope.

“We will analyze the chemical characteristics of incineration ashes from all across the U.S.,” Kumar said. “For the next two years, we will work with these ashes at the lab scale; but later, we will test the developed real-time characterization capability at waste incineration facilities nationwide.”

RADAR-X has multifaceted sustainability benefits. First, it decreases landfill waste — the U.S. incinerates approximately 34 million tons of municipal solid waste every year, and then these residues are sent to a landfill. Second, reused ashes decrease the need for raw materials, reducing the necessity of environmentally-harmful mining operations.

“The successful implementation of RADAR-X will reduce our collective environmental footprint. The project is relevant to everyone, whether they know it or not,” Kumar said.

Looking toward the future, Kumar plans to stay in the research field, specifically focusing on “green” chemistry. Clearly, his fascination with the study of questions without answers has never waned.

“That’s the beauty of research: When it comes to things that nobody has ever thought about, we are all blank. We all have our own ways of thinking. In the end, it boils down to where you want to lead yourself.”

 — Article by iSEE Communications Intern Maria Maring