WWEM - Abstract

Abstract Information :

Potable water reuse, especially more direct forms of potable reuse, requires effective treatment technologies and stringent monitoring for chemical and biological constituents of concern. Potable reuse applications commonly employ reverse osmosis (RO) with an advanced oxidation process (AOP) to remove organic compounds. However, a fraction of total organic carbon (TOC) in wastewater effluent makes it through RO/AOP. Of particular interest are organic compounds with low molecular weight that permeate RO, are recalcitrant in AOP, and are of human health. Some of these VOCs would not be detected during chemical peak events by conventional online organic carbon analyzers posing a safety risk to consumers. In this work, we developed an online method to detect volatile organic compounds (VOCs) for application to potable water reuse monitoring using thermal desorption, cavity ring-down spectroscopy (TD-CRDS). This method uses a direct sparge interface system for online, continuous flow wastewater sampling and VOC collection and can measure 19 VOCs of interest for RO-based potable water reuse applications in a 50-minute analysis method at a concentration of less than 0.1 ppb with relative standard deviations between 2-12%. The compounds chosen for this work include hazardous VOCs regulated by the EPA and in California and are expected to have limited RO and UV/AOP removal.