The Kasson wastewater treatment plant (WWTP) is upgrading to accept wastewater from the neighboring city of Mantorville in southern Minnesota. The Minnesota Technical Assistance Program (MnTAP) was enlisted to estimate the electrical conservation.

From mid-November through December 2015, MnTAP analyzed the electrical conservation potential of the Kasson WWTP and identified three opportunities to reduce operating costs:

• Dissolved oxygen control could save $13,000/year and 147,000 kilowatt hours (kWh, a measurement of electricity used): Kasson uses two secondary aeration oxidation ditches to break down organics. The oxidation ditches currently run near the minimum speed allowed by SCADA programming and are manually adjusted. The current electrical cost for secondary aeration is $36,300 per year. Current programming does not allow operation across the full design range of the system. Resolving current program issues and adding dissolved oxygen measurement to control aeration speed is estimated at $55,000 and will save $13,000 a year, with a payback of about 4.2 years.

Managing phosphorus is essential for protecting Minnesota’s lakes and rivers. Excess nutrients, primarily phosphorus, can ultimately lead to nuisance algal blooms in surface waters, a process called eutrophication.

In 2008, Minnesota adopted lake eutrophication standards, which set defined phosphorus, algae, and clarity goals for Minnesota’s lakes. In 2014, as a complement to lake standards, Minnesota adopted river eutrophication standards (RES) to set phosphorus and algae goals for rivers and streams. The rule includes five parameters:

• Total phosphorus
• Chlorophyll-a (Chl-a)
• Five –day biochemical oxygen demand (BOD5)
• Dissolved oxygen flux (DO flux)
• pH (Minn Rule 7050.0222 Subp. 2b.)

When analyzing appropriate WWTP TP effluent limits for a river or stream, MPCA staff use the cause (TP) and response variables (Chl-a, BOD5, DO flux, pH)  for RES to determine if a river or stream is meeting concentrations protective of the water body. At a minimum, TP and at least one response variable are needed to make this determination.

A water body is a complex system and elevated TP concentrations may not necessarily mean excess amounts of algae. To help understand these situations, MPCA may collect additional water samples to further explore the relationship between TP and Chl-a, BOD5, DO flux, or pH, where collected. If sufficient data are available for multiple response variables in a given location, MPCA will consider all of the data when determining if the water body is protected or not.

Using this methodology, MPCA assessed more than 3,100 river sections (where eutrophication data were available) and determined:

• 41 river sections fail to meet RES and will be included on the draft impaired waters list for 2016 (scheduled for release soon)
• 415 river sections do meet RES
• The rest need more data for a determination

For every river section reviewed, staff also considers WWTF current discharge rates in addition to the WWTF’s effluent at its permitted potential. Often the permitted load from facilities exceeds current discharge rates. As a result, effluent limits staff may determine new limits are necessary to maintain protection of rivers that are not currently impaired.

MPCA will continue to work to ensure healthy rivers remain protected and determine appropriate reductions in phosphorus where too much is getting to that water body. For more information, email phosphoruseffluentlimits.pca@state.mn.us.

The MPCA has begun rulemaking for the wild rice sulfate standard, which may affect some municipal wastewater treatment facilities that are upstream of wild rice waters. While most wild rice waters are in northern Minnesota, some are in central and southern regions.

As a next step in the rulemaking process, the MPCA plans to release a draft Technical Support Document (draft TSD) in July 2016, which provides a detailed description of the technical basis for any potential changes to the standard. Interested parties may provide input on this draft this summer.

Also at this time, the MPCA will release an updated draft list of wild rice waters where the standard will apply. WWTFs should check this list to see if they are discharging upstream of a wild rice water.

In addition, MPCA scientists will begin field work this summer to collect water and sediment data on a few proposed wild rice waters. This field work will continue in additional waters in the future as part of the agency’s ongoing intensive water monitoring efforts. Facilities may notice this sampling downstream of their discharge points.

The MPCA plans to publish the proposed rules along with the Statement of Need and Reasonableness (SONAR) early in 2017. The SONAR includes the MPCA’s rationale for any needed changes to the rule and a regulatory analysis with information about affected parties, economics, and alternatives considered.  This will be followed by a formal public comment period and public hearings.  The agency plans to complete the rulemaking by January 2018. 

Background on the wild rice sulfate standard

Minnesota adopted a sulfate standard of 10 milligrams per liter to protect “water used for production of wild rice” in 1973 based on past studies showing that wild rice was primarily found in low sulfate waters.  The wild rice sulfate standard came under scrutiny in the 2000s, and the Minnesota Legislature provided funding in 2011 for a wild rice sulfate standard study to better understand how sulfate and other substances affect the growth of wild rice.  This legislation also required the MPCA to undertake rulemaking to identify wild rice waters and any other needed changes to the standard.

MPCA posted a Request for Comments on Oct. 26, 2015, which marked the first “official” step for state rulemaking and is a legal requirement of the Administrative Procedures Act.  The MPCA received more than 600 comment letters, which the agency has reviewed carefully as it considers refinements to the wild rice sulfate standard.

For more information

For updates on the wild rice sulfate standard rulemaking, visit the MPCA’s website or contact Pat Engelking at pat.engelking@state.mn.us or 651-757-2340.

And the winner is…Liberty Paper, Inc. … and the city of Becker wastewater treatment facility … and lakes and streams in the Becker area … and waters downstream. The Central States Water Environment Assoc. recently named Liberty Paper its 2016 Industrial Achievement Award winner for the company’s proactive efforts to reduce environmental impacts relating to industrial wastewater. The MPCA recently featured the efforts in its online Above and Beyond series.

Liberty Paper has been recycling old corrugated containers into new paper for packaging in Becker, Minn., since 1995. As the company grew and increased its operation, it became apparent that it could no longer meet effluent limits in the wastewater being discharged to the Becker municipal wastewater treatment facility. After nearly two years of trucking excess wastewater to the Met Council wastewater facility in St. Paul to avoid violations in Becker, the company knew it needed to find a better solution. Working in partnership with the city of Becker, Liberty Paper built an effluent treatment plant at its mill, designed to reduce carbonaceous biochemical oxygen demand, or CBOD, by 80% or more. CBOD measures how much oxygen is depleted by organisms in water – the more pollution, the more oxygen used in its breakdown.

 The company’s $12 million treatment plant has been fully operating since 2013, and currently reduces CBOD by nearly 98%. No more trucking wastewater to St. Paul. No more worrying about how to meet limits at the Becker wastewater facility. And no more threat to the environment. Liberty Paper won the award, but the company knows it is not the only winner here.

Photo above: Liberty Paper employees, Tom Murphy, at left, and Jesse Moore in front of the company’s award-winning effluent treatment plant.

After hearing from several communities on the expensive damage to their wastewater treatment systems from personal wipes labeled as “flushable,” the MPCA worked to introduce legislation to change their labeling in Minnesota. This proposal would ban “flushable,” “septic safe,” or “sewer safe” labeling from nonwoven disposable products (wipes) sold in Minnesota. It would also require the packaging to include a “Do not flush” message.

The bill passed the Minnesota Senate, but died in committee in the House. Minnesota was the first in the nation to have a wipes labeling bill pass in one body of a state legislature. The agency plans to reintroduce the legislation in the 2017 session.

Until labeling changes, cities can use the online toolkit to educate their customers about disposing of wipes in the trash instead of the toilet. Here’s an idea for county fairs this summer:

• Set up a table with colored tablecloth
• Put two or three clear magnetic agitators filled with water on the table. If you don’t have agitators available, use two or three clear containers.
• Ask people passing by to put a wipe in the first agitator, toilet paper in the second, and facial tissue or something else in the third and guess how long it will take them to break down. Kids will love this!
• Make a poster to explain the display and place it on an easel or hang it above the table.
• Give away magnets with “Wipes Clog Pipes” on them (available in online toolkit).