Dissolved organic nitrogen (DON) has not received much attention by the drinking water
community despite the potential role of DON on disinfection byproduct (DBP) formation and
speciation, biostability of raw and finished water, and membrane fouling. The European
Community directive has a maximum admissible concentration for org-N of 1 mg Kjeldhal-N/L
(DON+NH<sub>4</sub>
<sup>+</sup>), but the US has no similar guidelines. Currently, there are no reports of DON fate
during water treatment. Furthermore, some chemicals added during water treatment (e.g.,
polymers) contain organic nitrogen and their contribution to DON in finished water has largely
been overlooked. As a first step in understanding the fate of DON during water treatment, this
paper provides evidence that some forms of DON are removed during alum coagulation.
Over the past two decades marine scientists, limnologists, and ecologists have studied DON,
offering several techniques for measuring DON concentrations and understanding DON
occurrence. DON is comprised of a broad spectrum of molecular weight compounds, including
amino acids, amides, heterocyclic-N, and lesser amounts of uncharacterized nitriles and
nitrosamines (Westerhoff et al. 2002). This paper summarizes DON concentrations and
DOC/DON ratios in over 14,000 surface waters based upon an analysis of USGS-NAWQA
datasets, which use a TKN method (ammonia + DON) with a TKN detection limit of 0.2 mgN/L.
The median DON concentration was 0.34 mg-N/L, although approximately 30% of the samples
had a TKN value of less than 0.2 mgN/L. Primary sources of DON in watersheds include:
upstream wastewater discharges; infiltration and runoff of organic fertilizers from agricultural
areas; excretion of algae products in eutrophic waters; urban runoff; and, forest litter.
DON concentrations in surface waters are commonly higher than groundwater levels. Despite
the information on DON sources, occurrence, and fate within watersheds, there has been no
interpretation of DON occurrence as related to the management of drinking water supplies. Includes 8 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 290 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 9 |
| Published : | 11/02/2003 |
