Characterizing and Evaluating the Treatment of Organic Compounds during Direct Potable Reuse

Abstract

The goal of direct potable reuse (DPR) is to ultimately produce compliant water that is suitable for drinking purposes in a timely and efficient manor; however, as DPR projects continue to gather attention, it raises questions about the monitoring process. With the quickly changing climate, water managers and regulators are often left to make decisions based from assumption of risk rather than recommendations made from scientific assessments. This dissertation illustrates that using a universal bulk organic parameter guideline, like total organic carbon (TOC) measurement, is too broad of a surrogate to accurately reflect exposure to small fractions of organics that may be harmful or toxic in a given water based upon treatment source and techniques applied. Altogether, this dissertation seeks to address the current gaps on evaluating DPR. There have been numerous analytical techniques developed throughout the past century to monitor the quality of water, with none having the ability to detect and/or quantify the full spectrum and composition of organic matter. Therefore, various types of analytical techniques capable of illustrating the groups of organic compounds present during and after advanced water treatment (AWT) was investigated. Ultimately, the most promising analytical tools investigated were then applied in a framework to characterization the organic composition of various DPR trains at different locations throughout the world. Data indicates all analytical measurements provide useful information about the composition of organic matter, but only certain methods performed proved to be effective and timely tools for monitoring water quality of DPR applications. A DPR monitoring framework was then proposed based on the data obtain from the DPR trains and local drinking water supplies. Briefly, bulk organic parameters are proposed to be analyzed on a continuous basis as a surrogate, where the targeted analysis should be applied as an indicator for treatment efficacy. Lastly, non-targeted analysis is proposed as a supplemental tool to illustrate the transformation of the water. Of the advanced treatment processes evaluated, which followed traditional wastewater treatment, the treatment trains of MF to RO to UVAOP was shown to have the greatest reduction of analytical signals for all techniques from the secondary effluent, followed by O3 to BAC to GAC treatment trains.