Bacterially Induced Struvite Growth from Synthetic Urine: Experimental and Theoretical Characterization of Crystal Morphology

Abstract

We describe the mineralization of struvite crystals from synthetic urine in the presence of Proteus bacteria. The presence of these bacteria causes a successive increase in the pH of the solution of synthetic urine. The effect of pH on the growth morphology of struvite crystals is studied. The results show that for pH in the range approximately from 7.5 to 9.0 struvite crystals take single and hemimorphic morphology. Crystal faces are different at opposite ends of the crystallographic c-axis, and thus polar crystal properties are permitted. At higher pH, many twin and dendritic crystals have been observed. It is suggested that the growth of dendrite is related with the bacterial substances which may serve as the sites for heterogeneous nucleation. The growth of single crystals is analyzed from a theoretical point of view based on relative growth rates.