05.03 - Brown Water Action Plan - Laserfiche WebLink

Home Browse Search

� City of Pequot Lakes Dear Madam Mayor and Council, What follows is an outline of possible options for remediation of the "Brown Water" situation currently in Pequot Lakes distribution system. The problem and its history — Iron and Manganese are natural elements in the ground and subsequently in the ground water, which is where we get our water from. Before the City built its water treatment plant, the city had a fairly extensive flushing and chemical addition program to reduce the smell and color of the water supply. Over the years the cast iron pipes built up a layer of iron and manganese scale on the inside of the water mains. This scale has like most things two sides to it; one is that the scale helps to keep the lead and copper from leaching into the drinking water, and two, the scale helps protect the pipe from corrosion and failure. What do we do about this brown water? Option 1— Like the last time this happened, the City did nothing ofiicial, but simply �— flushed the hydrants until the water cleared up. This first occurrence happened when Trailside estates water main was added to the distribution system. The change in flow patterns and velocity during flushing caused the some of the pipes to lose some scale. Now spring forward four years and once again add a new section of water main and flush it out, brown water returns. We had this almost cleared out when we had a small fire over at the Industrial park. The Firemen hook up to a hydrant, run lots of water, brown water back with a vengeance. On the iist occurrence I sent a sample in to A.W. research labs in Brainerd and had the water tested for Iron and Manganese, the results were as follows; Iron <0.10 ppm. Manganese <0.05 ppm. This means its drinkable. We also sent a larger sample to Sioux Valley Environmental to get an idea of what if any product would be recommended to remediate this problem from reoccurring in the future. �.. 4638 CoL1NTY Ro.� 11 • PI�,QUO7 LAKES, �11V 56472 •(218) 568-5222 • F�1k: (218) 568-5860 • wwwpequodakes-mn.gov