A Peek Inside Our New High-Tech Treatment Facility

It’s rare to find an opportunity to capture and clean polluted runoff from half a city. But that’s exactly what our new state-of-the-art treatment system is designed to do for St. Anthony Village.

The St. Anthony Regional Stormwater Treatment and Research System, slated for completion this summer, sits on a choke point for stormwater runoff. Nearly 600 acres of urban land drains through a single stormpipe on the border of St. Anthony and Northeast Minneapolis. Right now, that pipe carries an estimated 169 million gallons of untreated runoff — loaded with 61 tons of solids and nearly 400 pounds of phosphorus — directly into the Mississippi River each year.

The giant, bunker-like concrete structure you see in the photos is designed to grab as much of that polluted runoff as possible and run it through a series filtration devices — some simple, others high-tech. Together, these devices will remove an estimated 63 percent of solids and 47 percent of total phosphorus (including 18 percent of hard-to-remove dissolved phosphorus). We’ll be continually monitoring the system’s performance to track how well each of the different filters performs.

The entire facility will soon disappear underground as workers backfill around the site and restore the turf above it. In the meantime, enjoy these unique glimpses into one of our biggest and proudest clean water investments of 2016. You can also read more about the system and how it works on our project page.

A view of the half-constructed swirl chamber inside the St. Anthony Regional Stormwater Treatment and Research Facility.
A view of the half-completed “swirl chamber,” which will serve as the primary treatment mechanism. This part of the system separates out suspended solids (i.e. sediment and debris) from the stormwater. The solids can be vacuumed out of the chamber as part of regular maintenance routines.
A view from inside the distribution well, where water enters after leaving the swirl chamber.
A view from inside the distribution well, where water enters after leaving the swirl chamber. From here, the stormwater runoff will either re-enter the stormsewer system or move into one of the two secondary filters.
StormFilter cartridges
One of the two secondary filtration chambers is filled with StormFilter cartridges. This unique treatment system can be customized to remove specific pollutants from stormwater runoff. The StormFilter cartridges in the photo are filled with Phosphosorb, a proprietary product designed to filter out particulate phosphorus and absorb dissolved phosphorus.
A worker uses a shovel to spread iron-enhanced sand in one of the secondary filtration chambers.
A worker uses a shovel to spread iron-enhanced sand in one of the secondary filtration chambers. The sand is used to filter out particulate phosphorus; the iron is added to remove dissolved phosphorus. The MWMO is installing monitoring equipment to track and compare the performance of the iron-enhanced sand chamber with the StormFilter chamber.
A view of the fully constructed stormwater tank, with inflow and outflow ports visible on the near-facing wall.
A view of the fully constructed stormwater tank prior to being connected to the stormsewer system. Inflow and outflow ports are visible on the near-facing wall.

More Photos (on Flickr)

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