Investigation of nitrogen transformations in a southern California constructed wastewater treatment wetland

A 9.9-ha combined habitat and wastewater treatment demonstration wetland wa s constructed and planted in the summer of 1994, at Eastern Municipal Water District's (EMWD) Hemet/San Jacinto Regional Water Reclamation Facility (R WRF) in southern California. From January 1996 through September 1997, the marsh-pond-marsh wetland system was operated to polish an average of 3785 m (3) d(-1) (1 x 10(6) gal day(-1)) of secondary-treated effluent from the RW RF. Nitrogen removal was a major objective of this wetland treatment. Weekl y inflow/outflow water quality monitoring of the wetland was supplemented w ith biannual, 45-station synoptic surveys within the system to determine in ternal distribution patterns of the nitrogen species (total ammonia, nitrit e, nitrate, and organic nitrogen), total organic carbon (TOC), and ultravio let absorbance at 254 nm (UV254). Synoptic surveys were carried out during May 22 and September 17, 1996, and May 6 and September 25, 1997 and the res ults were mapped using the ARC/INFO processing package and inverse distance weighted mathematical techniques. Distribution patterns of the various nit rogen species, TOC, and UV254 within the wetland indicate that the nitrogen dynamics of the system are influenced both by variations in treatment plan t loading, and, increasingly, by the degree of coverage and maturity of the emergent vegetation. (C) 2000 Published by Elsevier Science B.V. All right s reserved.