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September 2017
The Minnesota Pollution Control Agency (MPCA) recently
released its proposed changes to Minnesota rules that are meant to protect wild
rice from certain types of pollution.
The proposed rule changes take into account the newest
evidence about how sulfate and sulfide affect wild rice. Peer-reviewed agency
research begun in 2011 found that:
- Sulfate in wild rice waters enters the sediment in which wild rice is rooted, and bacteria convert it into sulfide.
- Higher levels of sulfide in the sediment create an
environment that reduces wild rice growth and survival over time.
The existing rule (or standard) limits sulfate to 10
milligrams per liter in water used for the production of wild rice. However,
the MPCA’s new research indicates that sulfide in the sediment in which wild
rice grows is the pollutant of concern. The proposed rules are designed to limit
sulfide to 120 micrograms per liter.
The sediment sulfide originates from sulfate in the
water, but certain factors change the rate at which sulfate is converted to
sulfide in the sediment. Most significantly, higher levels of iron in the
sediment can lead to less sulfide, and higher levels of organic carbon can lead
to more sulfide. So while sulfate may create conditions that negatively affect
wild rice, no single level of sulfate can be protective of wild rice in all
bodies of water.
The rule proposal sets up a process to identify the level
of sulfate that is protective for each wild rice water: The MPCA will collect
sediment samples in wild rice stands and measure iron and organic carbon
concentrations, and then enter the data into an equation to determine the
numeric sulfate standard for that wild rice water. The agency will use the wild
rice rules to evaluate facilities that discharge to wild rice waters, such as
wastewater treatment plants, mines, and industrial facilities, and, over time,
determine if they need additional permit limits to protect wild rice.
The proposed rules also:
- Identify the lakes, rivers, and streams to which the standard applies, termed “wild rice waters.” While the list numbers about 1,300 wild rice waters, only about 250 are downstream of a facility with a permitted discharge. The MPCA estimates about 130 permitted facilities may receive additional limits to protect wild rice. The agency will evaluate their permits as data become available and permits come up for reissuance.
- Set out procedures for collecting and analyzing sediment to determine carbon and iron levels.
- Address some issues around implementing the standard, particularly at facilities with water discharge permits.
Public comment
period now open
The MPCA is now accepting public comments on the proposed
rules. Public hearings on the rule proposal are scheduled at locations around
the state between Oct. 23 and Nov. 2. Comments will be accepted until at least
five days after the last public hearing. (The final comment deadline is
determined by the hearing judge.)
To view all rule-related information visit: www.pca.state.mn.us/water/protecting-wild-rice-waters.
This information includes proposed additions to Minnesota Statutes, Chapter
7053, on effluent reviews as part implementing the rule changes.
If the rules are adopted, the MPCA would implement them over multiple
permit cycles, based on data and discharge reviews. The agency realizes that
treatment to remove sulfate is expensive and is prepared to take an approach
similar to implementing the chloride standard (see story below). This approach
would include granting variances to the rule to allow time for finding a
solution.
Comments must be submitted to the Office of
Administrative Hearings via the web (https://minnesotaoah.granicusideas.com/discussions), by mail (Office of Administrative Hearings, P.O. Box
64620, St. Paul, MN 55164), or in person (600 N Robert St., St. Paul, MN). In
your comments, you must include your name and address and identify the portion
of the proposed rules you are commenting on, your support of or objection to it,
and any change you are proposing.
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Earlier this year the MPCA released the recommendations of a work
group on implementing the chloride water quality standard in wastewater
discharge permits. Reducing chloride in wastewater is difficult, both
technically and economically, prompting the agency to convene a work group of
community representatives to study this issue. After months of study and
discussion, the group developed a decision tree for the MPCA to use in deciding
whether to assign a chloride limit with an associated schedule of compliance or
consider a variance to allow time to find a solution.
MPCA Commissioner John Stine formally adopted
those recommendations in a memo dated June 15, 2017. Since then, agency
staff have developed outreach materials for chloride and other salty
parameters:
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The decision tree will help MPCA work with the cities to determine next steps and the appropriate permitting tool for moving forward with the permit process.
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As part of the chloride variance permitting tool, a chloride variance request form and a variance eligibility tool spreadsheet with instructions are now available for use. This spreadsheet already has much of the economic information needed by MPCA to determine variance eligibility. That means cities should be able to fill out these forms on their own, avoiding the cost of hiring a consultant.
- The MPCA has used compliance schedules in the past to address these parameters, and compliance schedules are still and will continue to be an
available permitting tool.
Whatever permitting tool is chosen, the goal is the same: Reduce
the amount of chloride and other salty parameters entering the wastewater
plant. This remains the most cost effective way to protect Minnesota’s fish, aquatic
bugs and plants from chloride and other “salty parameters.” Work continues on
the best ways to do this. The MPCA hopes to share success stories in the
future. Until then, we will keep working with communities and facilities to
address this salty problem.
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If you have a Large Subsurface Sewage Treatment System
(LSTS) with a total nitrogen limit, your next permit may require different
monitoring to help your system function better.
Why are these changes being made? Recent studies suggest the need for more
“hands on” attention to LSTS to keep them in compliance with permits. (See the
studies online: "Best Practices
Improvements: Nitrogen Pretreatment Performance of Land Based Wastewater
Treatment Systems and “Small Community
Wastewater Treatment Program Start-Up Assistance and Management Evaluation.)
Some operators have also suggested adding these requirements to permits to
better focus on wastewater treatment process control needs.
What’s being changed?
Monitoring changes will only be made to new and reissued LSTS permits,
with end-of-pipe total nitrogen limits, that have a “Pretreatment Effluent
Station” (PES). Changes may include:
- Eliminate certified lab testing at PES for CBOD5, TKN, Chloride, TSS, and phosphorous.
- Require non-certified lab testing at PES for ammonia, nitrate, alkalinity, temperature, dissolved oxygen, and pH. These data will not be submitted with electronic discharge monitoring reports (eDMRs). Instead, the MPCA will require they be recorded and maintained at the treatment facility.
- Increase monitoring frequency at PES from quarterly to
weekly.
Will
this affect other sampling required by permits?
No. Certified lab testing is still required for all data reported on the
eDMRs, such as influent and effluent sampling stations. These changes will not
impact your permit limits.
How much will these changes cost? It depends on the testing methods you choose,
but the cost for this analysis could be less than you pay now, even with
increases in frequency of monitoring. If you already do internal treatment
process monitoring on a weekly basis, like the agency currently recommends for
LSTS with nitrogen limits, and have some basic lab equipment, you will save
money. That’s because the non-certified lab tests are low-cost in comparison to
certified lab testing. MPCA currently recommends that the operator visit the
site, for a Class C facility, at least weekly to perform routine operation and
maintenance tasks. The updated sampling requirements will provide the operator
with important data to verify that the facility is removing nitrogen as
designed.
What if I am interested in these permit changes before my
current permit is reissued? You may have
to request and pay for a permit modification prior to eliminating current
requirements for certified lab testing at a Pretreatment Effluent Station.
If you have any questions about these
LSTS permit changes, the recent LSTS studies, or operation and maintenance of
these systems, contact:
In recent presentations to permit
holders and legislators, a common question has been, “Isn’t the effluent limit
the same as the water quality standard?” The answer: “No. They’re certainly
related but they’re different. The standard is an ambient water quality goal.
It’s the target for lake or river water quality. The effluent limit is the goal
for the water discharged from a treatment facility. The limit is a legal
requirement in a permit based on avoiding negative impacts of the discharge on the
water quality standard.”
Another way to put it: The limit is
for the water coming out of the discharge pipe. The standard is for the water
in the lake or river receiving that discharge.
In setting the limit, the MPCA considers factors like the
volume of discharge, size of the receiving water, background concentrations,
and reductions from other facilities. For example, for
rivers in the southern part of Minnesota, the in-stream phosphorus standard is
0.15 mg/L, but the limit for a discharger to this river might be 0.50
mg/L. The limit may be higher than the standard because reductions from
neighboring communities are considered.
The standard sets the goal for the
lake or river. The effluent limit is one part of a strategy to get there.
The original “no discharge” field
on eDMRs
left many permit holders and even agency staff scratching their heads because
permit holders marked “yes” for “no” discharge. The field will soon read: “No
discharge/no flow occurred at this station” with permit holders marking X if
that’s the case. The “X” is not case dependent, meaning it can be upper or
lower case. If there was discharge, the permit holder leaves it blank. If you
have any questions, please contact your MPCA compliance
officer.
In May, MPCA industrial wastewater staff met with the Midwest Food Processor Association (MWFPA) in Rochester. The purpose of the meeting was to share information and concerns regarding the day-to-day operations at food processing facilities and NPDES/SDS permit requirements. MPCA staff were also updated on a research project that MWFPA and the Wisconsin Cheese Manufacturers Association initiated with the Wisconsin Department of Natural Resources to determine nitrogen losses and cover crop nutrient uptake from the land application of food processing wastewaters. The meeting was an opportunity for MPCA staff and permittees to discuss topics of concern and upcoming issues in an informal setting and get to know one another better. Participants hope to continue meeting annually. If you are a food processor and would like to be added to the list of interested parties for future meetings, please contact Jeff Stollenwerk, Industrial Wastewater Manager, at 218-302-6612.
Wastewater operators commented to the MPCA that it was difficult to find
both the Public Lands Survey System and coordinates to complete the location
fields on applications for wastewater discharge permits. The agency recently
added a data application to its Water Permits and Forms webpage that provides location
information in one place. Go to the Public Land Survey System (PLSS) Grid
for Permit Applications webpage, see the instructions embedded in the left pane,
zoom to a location, and the resulting pop-up is ordered to match the form. The data application is also linked from the MPCA water permits and forms webpage. For more
information, contact MPCA GIS Guru Casey Scott at casey.scott@state.mn.us
or 507-206-2652.
Other data viewers that wastewater professionals may find useful:
- Phosphorus loads and flow volumes: Summaries
of annual phosphorus loads and flow volumes discharged from wastewater
facilities since 2005. Users may click on individual facilities for details.
- Wastewater data
browser: Provides public access to monthly eDMR records. Application is
updated quarterly and allows users to either explore or download monitoring
data, permit limits, and details about facilities and stations.
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