A team led by Hongxu Zhou at the University of Illinois Urbana-Champaign has unveiled a promising method using woodchips and biochar to remove harmful pharmaceuticals and nutrients from wastewater, offering a potential solution for better water quality.
In a new study published in the journal of Hazardous Materials, researchers from University of Illinois Urbana-Champaign have discovered that combining woodchip bioreactors with a specialized form of biochar can significantly reduce both nutrient pollutants and common pharmaceuticals like ibuprofen in wastewater.
“Even at low concentrations, pharmaceuticals and personal care products (PPCPs) can degrade water quality, disrupt ecosystems, promote antibiotic resistance and lead to bioaccumulation in wildlife,” lead author Hongxu Zhou, a former doctoral student in the Department of Agricultural and Biological Engineering, said in a news release.
These pollutants, along with nutrients such as nitrogen and phosphorus, underscore the need for improved wastewater management strategies.
Woodchip bioreactors work by leveraging microbes that inhabit the woodchips. These microbes “eat” nitrate, converting harmful compounds into harmless nitrogen gas.
Zhou’s team enhanced this system by developing a designer biochar. Made from sawdust pre-treated with lime sludge and slow-burned into a charcoal-like material, this biochar can effectively bind with phosphorus and various PPCPs, ensuring these harmful substances are not re-released into the environment.
Testing their innovative “treatment-train” system, which they called B2 (bioreactor-biochar), the researchers ran nitrogen, phosphorus, ibuprofen, naproxen, the diabetes drug sitagliptin and a form of estrogen through the woodchip bioreactors followed by the biochar.
The results were impressive.
“On average, the B2 system removed 77% of the nitrate, 99% of the phosphorus, and about 70% of the ibuprofen, 74% of the naproxen, 91% of the sitagliptin, and 97% of the estrone,” co-author Wei Zheng, a principal research scientist at the Illinois Sustainable Technology Center (ISTC), part of the Prairie Research Institute at U. of I, said in the news release. “The biochar acted like activated carbon to efficiently remove pharmaceutical residues from the contaminated water.”
Interestingly, the study found that changing the water flow rate affected the efficiency of nitrogen removal, with slower speeds improving results. Meanwhile, using granule rather than pellet biochar proved better for absorbing pharmaceuticals and phosphorus.
Even though some bacterial community changes were noted within the bioreactors, the system’s ability to remove nitrates remained robust.
“For me, the most exciting aspect of our findings is the confirmation that the woodchip bioreactor’s nitrate efficiency remains unaffected by PPCPs,” added Zhou.
This indicates that the system could hold up well under real-world conditions.
Scaling the B2 system beyond the lab, the researchers modeled its potential effectiveness in larger applications. They believe that with regular maintenance and optimized design, challenges such as clogging can be mitigated, thereby ensuring the system’s sustained performance.
“We believe that through regular maintenance and optimizing system design, many of the challenges associated with scaling can be addressed,” added co-author Rabin Bhattarai, an associate professor in in the Department of Agricultural and Biological Engineering. “Ultimately, enhancing the effectiveness of B2 systems in addressing environmental challenges.”
With Zhou now continuing his work as a postdoctoral research associate at ISTC, the hope is that this innovative approach could pave the way for better wastewater treatment solutions, significantly improving water quality and ecosystem health.