Herald Journal - Enterprise Dispatch - Delano Herald Journal
Regional wastewater plant toured by commission members

November 3, 2008

By Jennifer Gallus
Staff Writer

Although still under construction, members get a sneak peek inside

HOWARD LAKE, MN - After a short meeting Thursday in Howard Lake, members comprising the Annandale/Maple Lake/Howard Lake Wastewater Commission toured the new facility under construction in Albion Township.

The tour began in the pretreatment building and followed the path that incoming wastewater will travel once the facility is up and running.

The pre-treatment building is where wastewater from the force mains enters the plant at the chemical-feed manhole, which then flows to the building.

Then it was on to the operation building, which is referred to as “the brains of the treatment operation.” Every process is controlled by the computer system in this building. The building houses the aeration blowers, sludge pumps, chemical storage rooms, a testing lab, an office, computer/control center, and a conference room.

Next the group went outside to view the anoxic basin and aeration basins. Wastewater flows from the pre-treatment building to this area, where bacteria use the organics in the wastewater as a food source.

From there, the group headed toward the final clarifiers, which are large, round concrete structures. This is where bacteria and solids are removed from the wastewater by settling to the bottom by force of gravity.

Bolton & Menk explained that “the decanted water, or supernat, in the top of the clarifiers contains very low concentrations of organics and solids. The sludge at the bottom of the clarifiers is collected by a mechanical rake, and then pumped back to the anoxic/aeration basins or the sludge storage tank.”

Then group moved on to the site of the future UV disinfection station. This is where intense light will penetrate the wastewater and kill disease-causing organisms.

The last stop was a quick look at the effluent lift station, which is where the disinfected effluent is pumped to the north fork of the Crow River.

“By the time the effluent reaches the river, it is considered to be cleaner than the river water,” Bolton & Menk Environmental Engineer Paul Saffert said.

Engineers said that the facility is still on schedule for completion in April 2009, and that everything is moving along quite well.

Earlier, during the meeting, the commission approved the plans and specifications, and to advertise for bids, (contingent on the approval of the MPCA) for the construction of Howard Lake’s lift station and force main.

The next meeting of the commission is scheduled for Thursday, Nov. 20 at 5 p.m. in Annandale.


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