Bioelectrochemical Approach for Urea Removal from Synthetic Urine

Abstract

The recycling of human urine has become a main research area in wastewater treatment due to the increased demand for water. Urine is composed of 95% water, 2% urea and other organic and inorganic compounds. Urea is a toxic molecule that may cause renal failure and gastrointestinal bleeding. Nevertheless, it is difficult to remove by common methods since it is a small, uncharged molecule. In this work, the use of Proteus vulgaris is proposed, a bacterium that contains urease, to catalyze the urea conversion to ammonia. The latter can then be oxidized by a platinum electrode while producing a current leaving a urea-ammonia-free solution. This system was first tested in synthetic human urine (SHU) simulating the ureolytic bacterium behavior. The ammonia oxidation current (AOC) was evaluated by cyclic voltammetry (CV) using Pt electrode in SHU, obtaining better results when less urea was present in solution. Preliminary, AOC was evaluated while the bacterial grew in Enriched Synthetic Human Urine (SHU + growth factors). The experiment was carried out for 24 hours showing not only bacterial viability and actual growth in the medium but an increased AOC over time.