Information About Manganese in Shrewsbury
Some areas of Town have experienced discolored water issues. This has been caused by a variety of activities occurring. Two water breaks back to back in the Boston Turnpike-Maple Ave area caused some sediment issues in the Sheridan Apartment complex area and parts of the Fairlawn area. A second activity with the closing of main gates for work associated with the new Whole Foods Market caused pipeline material to be stirred up affecting parts of Harrington Ave., associated side streets, and the Worthington Ave.-Fairlawn areas of Town. In addition to those incidents, the main line water pipe broke inside the Hebert’s Candy building necessitating a water main shutdown on Route 20 causing water issues in the Stoney Hill Upper Area.
Last week due to high demand the additional pumping created increased velocity in our main transmission line on West Main St. stirred up some loose sediment and manganese particles. As people used the water, it carried throughout the side streets and adjacent areas off the West Main Street Line. With high temperatures and drought conditions, we are limited in opening hydrants to flush out areas. We are however doing nighttime work presently on some of the most affected areas to address the issue. Until we correct the source problem and re-flush our entire system, these events will reoccur with every system disturbance.
Our water is safe to drink; we have recorded no total coliform bacteria anywhere in the distribution system. Common sense would dictate people use their judgement in consuming water that is discolored in their homes. We have provided several documents and links to external resources below that explains in detail about manganese as it relates to drinking water. Manganese is usually sequestered by a liquid linear phosphate solution. However, during system disturbances as described above, the manganese oxidizes out. And now visible it adheres to surfaces where before it stayed in liquid form. The concentration does not necessarily always increase. The best course of action for residents experiencing discolored water is to run their taps until the condition clears.
Please note; manganese between 100-200 ppb and periodically over 300 ppb is typically present in our water at all times.
It is also very important to remember the vast majority of manganese people acquire is from their diet. Below are food sources of manganese compared to our upper level of 300 ppb or 0.3 mg/L. (Amount in one liter which equals approximately 34 ounces of water)
- Soy based infant formula (No water added) 200-300 ppb
- Cow based infant formula (No water added) 30-50 ppb
- Brown Rice, cooked (½ cup) 1070 ppb
- Spinach cooked (½ cup) 840 ppb
- Green Tea 1 cup (8 oz.) 410-1580 ppb
- Black Tea 1 cup (8 oz.) 180-770 ppb
- Pineapple Juice (4 fl. oz. 630 ppb
- Pecans (1 ounce) 1280 ppb
- Pineapple, raw (1/2 cup) 770 ppb
- Whole wheat bread (1 Slice) 600 ppb
- Raisin bran cereal (1 cup) 780-3020 ppb
Long and short term solutions
Our Long range plan is to build a biological manganese filtration plant to fully address the manganese situation. We are approved on the State Revolving Fund list for 2% funding for the $14.5 million projected plant cost. We are listed second on the State priority list. This issue has been discussed at various Town Meetings. Pilot testing for two different methods of removal has been completed over the last two years. Approval for the bonding regarding this plant is scheduled at a Special Town Meeting this September 26th. Any permanent solution involves removing manganese at the source as it goes through the treatment facility. When constructed, this plant will be the largest in New England and one of the largest in the United States using biological filtration technology.
In the interim, the second element of our plan is the use of unidirectional flushing to clear first the main transmission lines. We then would move on to the remainder of the system starting at the Treatment Plant and working outward to all the extremities of our distribution lines. It is imperative that this flushing is done at low demand times (which are are spring and fall). As long as we have adequate water supply, we will begin October 1st and go as long weather permits (restarting in spring). This will be repeated annually.
In conjunction with the above system flushing, we will using a specific method called "Ice Pigging". The Ice Pigging process involved pumping an ice slurry into a pipe and forcing it along inside in order to scour the interior of the pipe and remove sediment. Ice Pigging will begin August 15th to clean especially difficult section of piping from the Plant as it enters our system. We will continue to use this method to work on all major transmission lines in the system.
As a result of this work, residents will start to see improvement in the short term and dramatic change when the new plant comes on line. Construction is scheduled to start spring, 2017 ending in the fall of 2018.
Please refer to the resources provided below for more information. If you have any specific questions or concerns, please call the Shrewsbury Water Department at 508-841-8506.
We thank you for your attention and your patience during this time.