Sarkhot, D. V. and Ghezzehei, T. A. and Berhe, A. A.
Journal of Environment Quality, vol. 42(5), pp. 1545 , 2013.
The use of biochar for recovery of excess nutrients in dairy manure effluent and the use of nutrient-enriched biochar as soil amendment can offer a robust solution for multiple environmental issues. In this study we determined the capacity of biochar, produced by pyrolyzing mixed hardwood feedstock at 300\,^∘C, to adsorb and retain or release two major nutrient ions: ammonium (NH4+) and phosphate (PO43−). We conducted the experiment using a range of nutrient concentrations that represent those commonly observed in dairy manure effluent (0–50 mg L−1 for PO43− and 0–1000 mg L−1 for NH4+). Up to 5.3 mg g−1 NH4+ and 0.24 mg g−1 PO43− was adsorbed from manure by biochar (18 and 50% of total amount in the manure slurry, respectively). During the desorption phase of the experiment, biochar retained 78 to 91% of the sorbed NH4+ and 60% of the sorbed PO43− at reaction times <24 h. Our findings confirm that biochar can be used for recovering excess nitrogen and phosphorus from agricultural water, such as dairy manure effluent.