Submitted to: Water Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/22/2005
Publication Date: 5/31/2005
Citation: Hernlem, B.J. 2005. "Electrolytic Destruction of Urea in Dilute Chloride Solution using DSA Electrodes in a Recycled Batch Cell." Water Research. 39(11):2245-2252
Interpretive Summary: This paper reports work that is part of a larger study of the applicability of electroflotation technology to manure lagoon water to minimize health risks (both animal and human) and environmental risks associated with manure lagoons. This particular work examined the changes in chemistry during treatment of water containing urea and other compounds found in manure lagoon water. The results show that temperature and other operating conditions affect urea nitrogen) loss and the levels of compounds useful for disinfection of pathogens.
Technical Abstract: The destruction of urea, its fate and influence on levels of active chlorine as well as formation of byproducts during electrolytic treatment of urea solutions was studied. Treated solutions designed to simulate typical concentrations in dairy manure lagoon water, contained initial concentrations of urea up to 750 ppm (mg/L), chloride from 100 to 400 ppm, and 2000 ppm NaHCO3. Current from 0.6 to 2.5 A (34 to 141 A/m^2)was applied using oxide coated titanium electrodes in a bench scale electrolysis device. Current and energy efficiencies of urea destruction increased with temperature and initial concentrations of chloride and urea. These parameters also affected the concentrations of oxidized chlorine species during treatment. Residual nitrogen was comprised of a constant fraction (0.07) of urea nitrogen oxidized to nitrate over the temperature range studied (16 to 34.5 C). Chlorate was also formed as a byproduct of electrolysis.