Behavior and characterization of residual organic compounds in wastewater used for indirect potable reuse

The scope of this study was to compare the behavior and character of dissolved organic carbon (DOC) during soil-aquifer treatment at different field sites in Arizona and California. To determine biodegradable and residual organic carbon, biodegradability studies using batch tests and a laboratory soil-column system were examined, combined with additional examinations for further characterization (ultrafiltration, adsorption analysis). Based on this comparison, soil-columns in series seemed to be more appropriate to simulate SAT as compared to batch-tests since this test system indicated continuous structural changes of generally poorly degradable organic compounds during SAT. This ongoing change of organic matter was confirmed by field measurements indicating biodegradation as the dominant removal process for DOC during SAT. The level of residual DOC after short-term SAT was similar although wastewater treatment processes differed at the investigated sites. However, increasing source water DOC led to an increase of residual DOG. In general, source water quality, drinking water and wastewater treatment should be viewed as one system in indirect potable reuse projects. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.