Effect of drinking water sources on reclaimed water quality in water reuse systems

The objective of this study was to investigate how natural organic matter from drinking water and soluble microbial products generated in the wastewater treatment process influence the character of dissolved organic carbon (DOC) in reclaimed water used for indirect potable reuse. Arizona and California water reuse field sites with different drinking water source quality and applied wastewater treatment were investigated using a watershed guided approach. Based on hydraulically corresponding samples of drinking water and reclaimed water, a correlation between the city of Mesa, Arizona, drinking water DOC and reclaimed water DOC after soil-aquifer treatment (SAT) was derived, indicating that up to 70% of the residual DOC after SAT originated from Mesa drinking water DOC. Based on nonpolar resin adsorption- (XAD-) isolation, followed by ¹³carbon-nuclear magnetic resonance spectroscopy (¹³C-NMR), residual DOC in reclaimed water after SAT was dominated at all investigated sites in concentration and character by natural organic matter and showed ¹³C-NMR spectra similar to the corresponding surface water isolates. The results imply that water-quality properties of source water play a key role in wastewater properties and variability and in subsequent soil-aquifer treatment impacts.