The end of construction is just around the corner for our Water Treatment Plant 1 (WTP1) expansion project. You are receiving this letter as part of our continuing effort to provide you with information and status updates related to our response to the February 2015 discovery of 1,4-dioxane in water supplied fromWTP1. Since July 2016, our water distribution system has been receiving water from the City of Minneapolis. The source of your water will change after the Labor Day holiday, when we transition back to water from New Brighton’s own wells.
WATER TREATMENT PLANT 1 (WTP1)
Water Supply and Construction Status
- Water Treatment Plant 1: WTP1 receives water from six wells located in the Prairie Du-Chien/Jordan aquifers. Water from these wells is treated using three distinct treatment systems:
- Green Sand Filtration System: This process removes naturally occurring iron and manganese.
- Advanced Oxidation Process (AOP): This process removes most TCAAP contaminants, including 1,4-dioxane (DX), using UV light and hydrogen peroxide. Installation of the AOP equipment is nearly complete, with plans for the manufacturer to start-up and test the system after Labor Day.
- Granular Activated Carbon: This process removes residual peroxide, as well as other TCAAP contaminants that are not removed by the AOP treatment process. Virgin carbon will be installed in these vessels in August, in preparation for plant start-up.
- Building Improvements: Construction is on schedule, with sky lights being installed for completion by the time this is published. Painting, plumbing, and HVAC upgrades continue throughout the building and the exterior brickwork will continue on the south side of the facility, in preparation for the installation of copper-colored paneling.
- Water Treatment Plant 3 (WTP3): WTP3 treats water pumped from two of the City’s deep wells, located in the Mount Simon/Hinckley aquifer. With WTP 1 under construction, staff opted to complete filter maintenance and upgrades at this plant. Tasks completed during this project include the replacement of one filter underdrain, support gravel and media replacement in both filters, installation of air wash equipment used during the filter backwash process, and the addition of a backwash water reclamation system (which allows for re-use of most of the backwash water). Progress continues, with a mid-August completion date.
- Water Treatment Plants 4 and 5 (WTP4 and WTP5): These plants each treat water from one of the City’s deep wells. Improvements at these plants include control upgrades and operational testing in anticipation of their use soon after Labor Day.
Transition Back to New Brighton Water
Shortly after Labor Day, City staff will begin the transition from Minneapolis water to New Brighton’s own water source. The Minneapolis Interconnection that has supplied water during the WTP1 expansion process will be closed, and the City will start its deep wells (and associated treatment plants – WTP3, WTP4, and WTP5). During the transition, Minneapolis water will be removed from water towers and flushed from the distribution system with water from New Brighton’s deep wells.
When the transition to the deep well source is done, WTP1 will be started. Water from WTP1 will be pumped to the Ground Storage Reservoir for testing. This may take some time, but when we are sure WTP 1 is producing safe and aesthetically pleasing water, it too will go back in service.
Summary – What You Need to Know
- Since April 2015, the City has been providing dioxane-free water to residents, initially by use of the City’s deep wells, and more recently by an interconnection with the Minneapolis water system.
- With the addition of AOP equipment and the completion of the WTP1 expansion and WTP3 upgrade projects, the water supply will be switched from Minneapolis back to New Brighton’s wells that supply its WTPs and distribution system.
- With the addition of the new AOP equipment at WTP1, the City’s state-of-the-art water treatment system will remove TCAAP contaminants, including 1,4-dioxane, to levels well below the Minnesota Department of Health’s most stringent drinking water standards.
- After the transition:
- New Brighton residents should adjust their water softeners to settings used prior to the transition to Minneapolis-supplied water.
- Aquarium owners should note that after the transition, water from the distribution system will again be disinfected using chlorine.
We appreciate your continued support for our efforts. Please note that the City will provide periodic water updates on the City webpage.
Dean R. Lotter
New Brighton City Manager