Dalhousie’s Centre for Water Resources Studies (CWRS) is home to an exceptional team of students, researchers, and professors constantly pushing the barriers of knowledge in fields related to water, our environment, and how humans factor into the equation. As part of their research, they also investigate new methods and instruments for monitoring water quality, and through this investigation were turned on to the potential for peCOD to be a valuable tool and asset for quantification of natural organic matter.
You can read the full application note by the CWRS team at this link. Below is an excerpt from the introduction:
Natural organic matter (NOM) present in surface drinking water sources has an impact on water treatment and can lead to health effects if not removed sufficiently. NOM can be monitored using a few different tools, however, new methods to understand and manage NOM in drinking water systems are constantly needed.
NOM is typically quantified by measuring the concentration of TOC, DOC, color and UV254 of the raw water. However, these conventional NOM metrics do not give much specific information on the nature of NOM, its treatability, or its reactivity. Chemical oxygen demand (COD) is the amount of oxygen required to fully oxidize NOM and is typically measured using a standard method requiring hazardous chemicals. The current method works for COD concentrations > 50 mg/L and becomes less accurate when adjusted for concentrations between 5 and 50 mg/L. Alternatively, the peCOD (photoelectrochemical chemical oxygen demand) analyzer is an instrument that measures chemical oxygen demand COD using a photoelectrochemical method. In contrast to standard COD methods, the peCOD analyzer has a detection limit of 0.5 mg/L.
The rapid speed of the peCOD method (~5 minutes) combined with the high accuracy of results delivered by the instrument, even at low concentrations required for treated drinking water, allow the instrument to be used operationally by treatment plants. In addition, peCOD uses only green chemistry, with no hazardous waste or reagents, allowing it to be used directly in plants by operators controlling the treatment processes. The peCOD gives them the water quality information they need, when they need it.