Sustainable Use of Bioenergy Byproduct: Biochar for Nutrient Removal from Wastewater

Biochar, byproduct of pyrolysis for bioenergy production, is a good adsorbent of nutrients and pollutants from wastewater (WW). Efficiency of nutrient removal by biochar is dependent on the feedstock used. Removal of nitrogen (N) and phosphorus (P) from WW was evaluated using a commercial biochar, from Dynamotive company (DY), activated carbon (AC), or biochars produced from peanut hull (PH), bagasse (BG) or hickory wood (HW), at rates 2.5 to 100 g L-1 WW. Removal of NH4-N by DY and PH biochars increased significantly with an increase in biochar rate. In the case of BG and HW biochars, the highest removal of NH4-N was at 25 g L-1 rate. Removal of NH4-N by AC was extremely low, except at 100 g L-1 rate. The Ortho-P adsorption from WW increased with increasing rates of biochar, except for PH biochar. This study demonstrated that most of the biochars, except PH biochar, are more effective than AC in removal of NH4-N and P from wastewater. The N and P enriched biochar can be used as soil amendment to agricultural soils to supply nutrients and enhance carbon sequestration.