Monitoring phosphorus is challenging because it involves measuring very low concentrations down to 0.01 milligram per liter (mg/L) or even lower. Even such very low concentrations of phosphorus can have a dramatic impact on water, such as the Chesapeake Bay.
Over past several years, spikes in phosphorus and nitrogen have forced the Cape Charles wastewater plant out of compliance—the Department of Environmental Quality has levied heavy fines in response.
To stay in front of potential problems, the town has begun on-site testing for nutrient levels.
Below is a chart of the on-site testing results, which seems to indicate that the town is still struggling to calibrate the tests. The blue line graphs the results of the on-site tests, and the gold line is the (official) results from the DEQ lab.
David Boyd says
Have they hired someone who actually has formal training – like a real degree in the appropriate field – to do this testing? The town numbers are getting a bit closer, but they are bouncing all over the place compared to the almost flat line from the HRSD lab. There has got to be a reason for that.
Looks to me like the HRSD numbers are some kind of average, while the town numbers are individual test results. That would account for a lot of the difference in variability.
I’m not disparaging the efforts of the town employees, but it looks like they may well be in over their heads. Saving money on fines might well pay for hiring a professional.