FURI | Summer 2020

Enzyme-Induced Carbonate Precipitation Using Fresh Urine and Calcium-Rich Zeolites

Enzyme-induced carbonate precipitation (EICP) is a soil cementation technique that utilizes free urease enzyme to hydrolyze urea into carbonate ions; in the presence of calcium ions, calcium carbonate is precipitated. Fresh urine has been demonstrated to be a unique source of urea for EICP. However, a major concern is the ammonium ion byproduct. Zeolites were evaluated as an adsorbent of ammonium ions; varied doses and forms of zeolites were tested in beaker experiments using synthetic and real fresh urine. Preliminary experimental results demonstrate the efficacy of calcium-rich zeolites to adsorb ammonium and produce calcium carbonate for EICP.