United States	Office of Water
Environmental Protection	EPA 820-F-20-001
Aaen°V	June 2020
OPTIMIZING FOR RESULTS IN MONTANA
POTW operators engage with training and onsite assistance
Operators at some publicly owned treatment works
(POTWs) have sought to optimize their operations
with simple changes, such as cycling aeration on
and off, modifying diffuser membranes, and raising
mixers. Optimization can reduce nutrient discharges
and delay or avoid costly capital expenditures
associated with advanced nutrient treatment
technologies. Operators may decide to optimize to
save money on those expenditures, to save energy,
to meet nutrient permitting requirements—and
because they take pride in producing high-quality
water.
The EPA's National Study of Nutrient Removal and
Secondary Technologies investigates efforts to
reduce effluent nutrient concentrations across the
country. This fact sheet shows how a statewide
approach succeeded in Montana.



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The Montana Department of Environmental Quality
(MT DEQ) partnered with POTWs to help improve
nutrient removals without costly upgrades to
advanced treatment technologies. In 2012, supported
by consultant Grant Weaver of CleanWaterOps,
MT DEQ assisted POTW staffs through classroom
training and onsite consultation. Recommendations
emphasized nitrogen removal through low-cost
modifications and monitoring adjustments in day-
to-day plant operations. MT DEQ has continued to
offer annual statewide training on nutrient removal
through optimization and onsite technical assistance
to POTW staffs since beginning the partnership.
Twelve mechanical POTWs actively engaged with the
training and consultation provided in that first year:
four conventional mechanical treatment systems,
not originally built for nutrient removal, and eight
advanced nutrient removal treatment systems. The
graph shows how their total effluent nitrogen levels
changed, from before the optimization training
through the most recent year available (2018).
Monitoring data were collected from the EPA's
Integrated Compliance and Information System-
National Pollutant Discharge Elimination System
(ICISNPDES), and treatment system information was
gathered via a review of NPDES permits with input
from Grant Weaver.
National Study of Nutrient Removal and Secondary Technologies
Nutrient removal through optimizing plant operations

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The conventional treatment systems
reduced their nutrient discharges,
showing that investment in staff
training coupled with operational
changes produces nutrient removal
benefits, even in systems not designed
for nutrient removal. Moreover, the conventional
mechanical treatment plants achieved effluent total
nitrogen levels comparable to those from much
more expensive advanced treatment plants. For
conventional mechanical treatment systems seeking
to remove more nutrients, optimizing can be a
less expensive alternative to advanced treatment
upgrades.
Effluent Total Nitrogen Levels at Conventional and
Advanced Treatment POTWs
Average TN Concentration (mg/L)
Average Effluent of Four Conventional Plants vs.	Average Effluent of Eight Advanced Plants
2010
2011
2012
2013
2014
2015
2016
2017
2018
Optimization Opportunities and Benefits
Although not required, these attributes can give operators interested in optimizing a head start:
» Ability and motivation to dedicate the time and	» Automatic process control
effort needed to achieve results.	instrumentation and one to two years of
» Participation in local classroom training or	standard process monitoring data, including
onsite consultation services.	influent and effluent nutrient and organics
» Excess plant capacity or tankage.	concentrations.
Capital savings coupled with better effluent quality make optimization a winning strategy for many
communities.
Acknowledgements
Monitoring data were collected from EPA's Integrated Compliance and Information System-National Pollutant Discharge Elimination
System (ICIS-NPDES) and treatment system type (conventional system or advanced nutrient removal system) was gathered via a
review of NPDES permits. This factsheet was prepared in collaboration with Grant Weaver of CleanWaterOps, who provided support
to MTDEQ and EPA Region 8 in improving nutrient discharges at POTWs in Montana.

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