Health Canada has released its Proposed Guidance on Natural Organic Matter (NOM) in Drinking Water.
For the first time, chemical oxygen demand (COD) has been listed as a parameter for monitoring and treating NOM. The peCOD method, developed by Guelph, Ontario-based MANTECH is referenced as it provides the sensitivity and speed of measurement applicable for source and treated drinking waters.
“COD has long been recognized by the drinking water academic community for monitoring source and treated drinking water, measuring treatability, and protecting public health,” says MANTECH’s President & CEO, Robert Menegotto. “With climate change resulting in variable and increasing NOM concentrations, having this critical method endorsed by the government is a major win.”
“Prior to the peCOD method, COD was the missing tool in the operator tool box along with TOC/DOC and UV254,” he says. “Now with the peCOD method, the COD parameter is easily utilized by water treatment plants and laboratories alike. By adding this parameter with a <5ppm limit, following the peCOD method, Canada is demonstrating its commitment to clean water advances, which is an important step toward making this particular method mainstream elsewhere around the world.”
peCOD follows ASTM international Method D8084 offering the advantage of measuring reactivity or oxidisability. The EU lists oxidisability with a water quality limit of 5ppm in treated drinking water; however, the costly, time-consuming, and hazardous permanganate method is referenced. peCOD COD generates results in 3-5 minutes with a safe and simple method. It provides valuable information that is different than TOC/DOC and UV254; useful for event detection, optimized coagulation and DBP formation potential.
For example, it was reported that the reactivity of the raw water for Winnipeg, Manitoba, (DOC = 7.9 mg/L) was approximately half that of Repentigny, Quebec, (DOC = 7.1 mg/L) resulting in higher DBP’s for Repentigny. peCOD provides a quick, accurate method for determining reactivity that both laboratories and plant operators can utilize. In the treatment plant directly, operators can utilize the peCOD 24/7 testing incoming and multiple treatment points.