Clear the issue on nitrates
Last Saturday at a public meeting I had the opportunity to speak with Sen. Ken Rozenboom and Rep. Larry Sheets here in Centerville. It was an interesting meeting with lots of topics covered. I asked a question about water quality, about when exactly a fine is levied for a manure spill. My question was never really answered. During the water quality discussion Sen. Rozenboom said that nitrates are removed by Bill Stowe, CEO of Des Moines Water Works, and put back into the water that flows downstream. That comment was not exactly correct.
I have communicated with DMWW and here is some of what they told me about nitrate removal....
“Our removal facility is a last resort treatment option. We have invested millions of dollars into alternative treatment options so we don’t have to rely on the removal facility. Up until last year, we had not utilized the removal facility since 2007. Some of these alternative options are:
- Off river storage that has natural denitrification. Examples of these storage areas would be our park ponds here at Fleur Dr. We see almost complete denitrification in these ponds. We have plans, in the budget for this year, to increase our usage rate of these ponds. We are going to be able to obtain 10 million gallons a day from these ponds after the capital improvement plan is finished.
-We also have similar ponds at our McMullen Treatment Plant. Maffitt Reservoir is used for emergency water supply also. Emergency supply can be for drought reasons or treatment needs. In the near future we plan on being able to use 15-20 million gallons a day from these ponds and the reservoir.
Even with these other options in place there may be times that we must run the removal facility. Unfortunately we do return some nitrate to the Raccoon River. We have calculated the nitrates that are returned to the river to be less than 0.2% of the total daily load we see in the Raccoon River. We are currently exploring new options so we do not have to run the removal facility or have nitrate residuals to dispose of.