Transformation of effluent organic matter during subsurface wetland treatment in the Sonoran Desert.
The fate of dissolved organic matter (DOM) during subsurface wetland treatment of wastewater effluent in a hot, semi-arid environment was examined. The study objectives were to (1) discern changes in the character of dissolved organics as consequence of wetland treatment (2) establish the nature of wetland-derived organic matter, and (3) investigate the impact of wetland treatment on the formation potential of trihalomethanes (THMs). Subsurface wetland treatment produced little change in DOM polarity (hydrophobic-hydrophilic) distribution. Biodegradation of labile effluent organic matter (EfOM) and internal loading of wetland-derived natural organic matter (NOM) together produced only minor changes in the distribution of carbon moieties in hydrophobic acid (HPO-A) and transphilic acid (TPI-A) isolates of wetland effluent. Aliphatic carbon decreased as a percentage of total carbon during wetland treatment. The ratio of atomic C:N in wetland-derived NOM suggests that its character is determined by microbial activity. Formation of THMs upon chlorination of HPO-A and TPI-A isolates increased as a consequence of wetland treatment. Wetland-derived NOM was more reactive in forming THMs and less biodegradable than EfOM. For both HPO-A and TPI-A fractions, relationships between biodegradability and THM formation potential were similar among EfOM and NOM isolates; the less biodegradable isolates exhibited greater THM formation potential.
Office of Arid Lands Studies, The University of Arizona, Tucson, AZ 85719, USA. quanrud@email.arizona.edu
David M
DM
Quanrud
Martin M
MM
Karpiscak
Kevin E
KE
Lansey
Robert G
RG
Arnold
D001130:Arizona; D001673:Biodegradation, Environmental; D002244:Carbon / Q000032:analysis / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D009930:Organic Chemicals / Q000032:analysis / Q000737:chemistry*; D010084:Oxidation-Reduction; D012621:Seasons; D014865:Waste Disposal, Fluid / Q000379:methods*; D014872:Water Movements
D009930:Organic Chemicals; D002244:Carbon