HomeMy Public PortalAbout7b. Option 1 -hdr-brewing-up-solutions-for-nitrogen-removal-optimizationBrewing up Solutions for
Nitrogen Removal Optimization
Many communities throughout the United States are increasingly
dealing with stringent nitrogen effluent limits, leading many to
invest in costly nitrogen removal infrastructure upgrades at their
wastewater treatment plants. Often, one of the limiting factors
within a nitrogen removal process is the availability of carbon. In
these situations, communities must often inject alternative carbon
sources such as microC, glycol or methanol, which can be both
expensive and create hazards with respect to storage and handling.
Separately, an increased demand for craft beer and spirits has
resulted in a boom in the micro-brewery and distillery industry.
As with anything “micro,” cost control is critical in order to ensure
long-term financial viability since the volume of product is limited.
One potentially significant cost to micro brewers can be the cost
of treating and hauling the waste by-product to an appropriate
disposal site, or paying the municipal fees associated with
discharging high strength waste into a public collection system.
In 2017, HDR tasked its employees to develop innovative ideas that
were judged collectively by their peers. This process enabled the
creation of a pilot program in 2018 that studied the viability of using
brewery and distillery waste as a cost-effective carbon source for
nitrogen removal in treatment plants. Here’s how we anticipate the
partnerships and benefits of putting this by-product to beneficial
use will play out:
BREWING HAULING AND
STORAGE
WASTEWATER
Imagine a Low-Cost
Reduction of Nitrogen Limits
in Your Wastewater
Nearly every state in the nation already has, or will
soon have, established nutrient criteria for their
lakes, rivers and streams. Stricter nutrient criteria
means more advanced treatment is required
to meet effluent permit limits. The microbial
populations in the wastewater treatment process
need food in the form of carbon to remove nitrogen.
In order for nitrogen levels to continue to be
reduced, additional carbon needs to be added to
the system. However, proprietary carbon-based
products are expensive (maybe as much as $6 per
gallon), are often shipped from very long distances,
and in some cases are hazardous to human health.
Utilizing local sources, HDR has successfully
implemented the collection and dosage of
brewery wastewater into the post anoxic zone of a
wastewater treatment plant, and has shown that
the process can decrease effluent nitrogen levels.
BREWING
Creating Local Partnerships with
Breweries & Distilleries
Microbreweries are a fast growing industry and every brewery
creates a high strength waste stream that must be disposed of in
some fashion. Disposal of this waste can negatively impact the
environment and significantly impact the economic and financial
viability of this industry.
Hauling and Storage
The HDR pilot study involved using a vactor truck to collect and
transport the brewery waste to the wastewater treatment plant
and the subsequent storage of the waste in a tank on-site. The
breweries utilized during the study were selected in part based on
the logistical feasibility of collecting waste from the brewery.
“This brewery waste approach
offers wide applicability to
municipalities across the
country that are searching
for a cost effective way to
increase their plant nutrient
removal performance.”
Cora
Revis
“Our pilot study is a win-win
solution for the community of
Bozeman – we were able to
collaborate on groundbreaking
technology with our client to
find an affordable solution
to future stringent effluent
limits, while also providing
a local small business with a
sustainable and affordable
solution for disposal of
brewery waste.”
Bill
Buxton
Coralynn.Revis@hdrinc.com William.Buxton@hdrinc.com
HAULING AND
STORAGE
Bozeman
CASE STUDY
In the summer of 2018, HDR
collaborated with the City
of Bozeman to provide the
engineering support behind
our “Brewing up Solutions for
Nitrogen Removal” pilot study.
WASTEWATER
Step 1:
Select and coordinate with a utility partner to model the treatment
process (we already had the model for Bozeman’s system), to determine
pilot study conditions and parameters, monitoring and analysis of data
in order to make changes to the process, and preparation of a pilot study
report. Bozeman’s plant is a 3MGD facility that achieves typical nutrient
season performance in the range of 4 mg/L total nitrogen and 0.16 mg/L
total phosphorus.
HDR also provided the necessary coordination between all interested
parties and the Montana Department of Environmental Quality (MDEQ).
Step 2:
Coordinate with local breweries and distilleries to solicit interest in the
pilot, sample and test waste product prior to process modeling, purchase
and installation of a temporary storage tank and feed pump, process
operation, and data collection. For this pilot, HDR collaborated with MAP
Brewing in Bozeman, MT, a local craft brewery.
Step 3:
Arrange hauling of the waste product from the brewery to the City of
Bozeman’s wastewater treatment plant. For the pilot, the City offered to
utilize a vac-truck to collect and transport the waste to an on-site storage
tank at the wastewater treatment plant.
Step 4:
Dose for 1-week in a single bioreactor train for 12 hours, with a nitrate
probe at the end of the train. Preliminary estimates were that 350 gallons
would be needed, but in actuality 500 gallons were required for the
brewery waste to be effective.
Step 1 Step 2
Step 3 Step 4
hdrinc.com
Results:
The results of the study validated the theory that injecting
brewery waste to the right stage of the wastewater
treatment process would lower nitrogen levels. During the
dosing periods of the study, the test bioreactor was able to
achieve total nitrogen concentrations of 0.5 – 2.0 mg/L
lower than those achieved in the control bioreactor. There
was a clear, and at times significant, reduction in nitrate
concentrations in the dosed bioreactor compared to the
concentrations in the control bioreactor during the testing
periods. When the brewery waste ceased being dosed
to the test bioreactor, the nitrate levels increased and
returned to those found in the control bioreactor.
In summary, a novel and cost effective way to comply
with increasingly stringent nutrient standards is offered
by injecting brewery waste into the right stage of the
wastewater treatment process. The results of this brewery
waste project will be pertinent to nutrient standard
compliance efforts across the country, and offer wide
applicability in their potential to be replicated elsewhere.