Application of photoelectrochemical chemical oxygen demand to drinking water

This study investigated the use of a photoelectrochemical chemical oxygen demand (peCOD) analyzer for the detection of natural organic matter (NOM) from four drinking water treatment plants in Nova Scotia, Canada. This novel method was investigated because it can measure NOM within 5 minutes and does not require hazardous reagents. As an initial research step, eight model organic compounds were used to demonstrate instrument feasibility. The study found that peCOD could accurately detect oxygen demand based on theoretical chemistry concepts (i.e., theoretical oxygen demand). The next step in the study evaluated NOM removal in practice. Specifically, a drinking water–plant survey found that the removal of NOM, as measured by peCOD, was approximately 3.5 times greater than the removal using traditional NOM surrogates—e.g., total organic carbon (TOC). This expanded scale in resolution highlighted the instrument’s ability to provide detailed information on treatment performance that was often more subtle with traditional NOM techniques. Expanded Summary