About 80 to 90% of nitrogenous matter excreted by mammals is urea. It is by far the most important synthetic fertilizer. Urea is also an ingredient of many consumer products, including soaps and skin care products. Urea is not considered as harmful.

There are 2 well-known approaches to detect urea in water. One being based on a color reaction of urea with diacetylmonooxime, the other based on quantification of released ammonium after enzymatic reaction with urease. Both methods are well worked out and sensitive down to the sub-ppm-range.

A new online-detector has been developed by DOC-Labor Dr. Huber. The urea is separated by SEC (Size-exclusion chromatography) from other organic and inorganic compounds. Due to the non-ionic and hydrophilic character of urea, it can also be separated from other molecules like nitrate and ammonium. After oxidizing the species at 185 nm within a special designed reactor (DONOX-reactor), the resulting species, nitrate, can be analyzed by a UVD detector at 220 nm in the low ppb-range.

The goal of my work is to determine the natural mobility of urea in diffuse (soil runoff) and non-diffuse (sewage) waste water pathways. It is from interest whether urea is fully degraded within a typical treatment.