Woodchips and biochar combined to clean pharmaceutical wastewater

The study, published in the Journal of Hazardous Materials, took place at the University of Illinois Urbana-Champaign.

“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. While nutrients like nitrogen and phosphorus cause visible problems like harmful algal blooms, PPCPs pose potential risks, particularly through long-term exposure in vulnerable populations. Both issues highlight the need for better wastewater management,” study author Hongxu Zhou said in a statement.

Zhou and his collaborators knew woodchip bioreactors - woodchip-filled tanks or trenches through which water flows - efficiently remove excess nitrogen in water. This is due to microbes living in and on the woodchips that ‘eat’ nitrate, turning it into nitrogen gas.

The team developed a novel designer biochar - sawdust pretreated with lime sludge and then slow-burned into a charcoal-like material – that could bind phosphorus and certain PPCPs. The large surface area and composition of the designer biochar cause chemical compounds to strongly adhere to it.