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M E M O R A N D U M
(June 18, 2019)
To: Shana Yelverton, City Manager
From: Rob Cohen, Director of Public Works
Subject: Approve an annual purchase agreement for providing odor
control treatment at City wastewater lift stations with Premier
Magnesia, LLC. in an amount not to exceed $140,000 for a 12-
month period.
Action
Requested: Approve an annual purchase agreement for providing odor control
treatment at City wastewater lift stations with Premier Magnesia,
LLC. in an amount not to exceed $140,000 for a 12-month period.
Background
Information: The City pre-treats the wastewater flows at the Shady Lane and
Lonesome Dove wastewater lift stations before it flows to the Trinity
River Authority (TRA) treatment plant. The pre-treatment with
Thioguard is necessary for several reasons including controlling
odor, maintaining infrastructure integrity, breaking up grease, and
managing treatment costs.
The City has to pre-treat the wastewater to manage the effects of
hydrogen sulfide gas in the sewer system. Hydrogen sulfide gas
has a very strong “rotten egg” odor and is highly corrosive to
concrete manholes and the cast iron manhole ring and lid . Treating
with Thioguard provides odor control that would otherwise have an
impact on residents. In addition, it aids in the reduction of said gas,
so the integrity of the wastewater infrastructure is not compromised.
Premier Magnesia has been providing Thioguard for Southlake
since 2006 because previous attempts to control the hydrogen
sulfide with other products were not successful.
Another benefit to this technology is the preventio n of grease
buildup in the wastewater lift station wet-wells and downstream
sewer mains. Grease causes blockage in the mains that may lead
to potential sewer overflows and Texas Commission on
Environmental Quality (TCEQ) fines. Additionally, TRA charges the
City a surcharge for high levels of BOD (Biochemical Oxygen
Demand) attributed to grease in the wastewater flows. In utilizing
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this chemical treatment, it eliminates the need for City crews to
remove and dispose of excess grease.
Financial
Considerations:
Funding for odor control treatment at the City’s wastewater lift
stations is provided in the annual Public Works Wastewater
Operating Budget. Under the proposed agreement, the cost per
gallon will increase from $2.84 per gallon to $2.91 per gallon for the
upcoming year. Premier Magnesia is a sole source provider for
Thioguard technical grade magnesium hydroxide slurry.
The increase per gallon will not affect the overall annual costs, as
the usage between Lonesome Dove and Shady Lane lift stations
will decrease from previous usage levels.
Strategic Link: This item links to the City’s Strategy Map strategic focus area of
Performance Management and Service Delivery. It specifically
relates to the City’s Corporate Objective, B2: Collaborate with
Select Partners to Implement Service Solutions and F2: Invest to
Provide & Maintain High Quality Public Assets.
Citizen Input/
Board Review: N/A
Legal Review: N/A
Alternatives: The City Council may approve or deny the agreement.
Supporting
Documents: Attachment A: Premier Magnesia, LLC - Thioguard Annual Contract
Pricing
Attachment B: Premier Magnesia, LLC - Sole Source Letter 2018
Staff
Recommendation: Approve an annual purchase agreement for providing odor control
treatment at City wastewater lift stations with Premier Magnesia,
LLC. in an amount not to exceed $140,000 for a 12-month period.
Staff Contact: Rob Cohen, Director of Public Works
6/3/19
Rob Cohen
Director of Public Works
1950 East Continental Blvd
City of Southlake, Texas 76092
Re: Premier Magnesia, LLC – Thioguard® Annual Contract Pricing FY 2019-2020
Rob:
Pursuant to your request for a renewal of the annual contract for Thioguard, I am submitting
this letter to update you on the terms of the agreement. You may submit Purchase Orders
either on a per load basis, or a Blanket PO may be issued for the duration of the price in effect.
The price per gallon for the upcoming year will be $2.91 effective July 1, 2019 through and
ending June 30, 2020. Price increase is being driven by a rise in delivery costs associated with
deliveries into the City of Southlake. Annualized transportation delivery costs for 2018 were
$0.56/gallon. Current transportation and delivery costs for 2019 (to date) are $0.65/gallon,
necessitating the increase.
In addition, manufacturing costs for Chemical Products (PPI) have shown an increase in
Chemical production costs from 275 in 2018 to 282 in 2019, resulting in a 2.54% change. That
index can be found at the end of this letter.
At the current combined rate of usage for Lonesome Dove and Shady Lane of 120 - 130 gallons
per day, estimated annual costs are between $127,458 and $138,080 if the current BOD loading
to these stations stays constant. However, ongoing analysis points to a higher BOD level in the
collection system line that feeds Shady Lane, and consequently Round Hollow, which may result
in the need to feed additional chemical to treat these lines in the future. Current levels of
treatment measured by pH values indicate good Hydrogen Sulfide and corrosion control in the
collections system at this time.
Compilation of Testing Data
Date Location
Analysis Results
pH Std/Units BOD mg/L
10/31/2016 Lonesome Dove NT 74
10/31/2016 Shady Lane NT 433
10/31/2016 Round Hollow NT 221
10/31/2016 Dove Road NT NT
3/2/2017 Lonesome Dove NT NT
3/2/2017 Shady Lane 8.14 386
3/2/2017 Round Hollow 8.15 170
3/2/2017 Dove Road 7.94 140
6/7/2017 Lonesome Dove NT NT
6/7/2017 Shady Lane 7.96 188
6/7/2017 Round Hollow 8.44 186
6/7/2017 Dove Road 8.54 81
3/22/2018 Lonesome Dove 9.23 100
3/22/2018 Shady Lane 9.27 264
3/22/2018 Round Hollow 9.52 324
3/22/2018 Dove Road 9.35 38
5/28/19 Lonesome Dove 8.44 Pending
5/28/19 Shady Lane 8.37 Pending
5/28/19 Round Hollow 8.22 Pending
5/28/19 Dove Road 8.59 Pending
Premier Magnesia very much appreciates your cooperation and looks forward to a continued
long-term relationship as a quality supplier.
Sincerely,
Mary P. Evans
South Central Regional Account Manager
Premier Magnesia, LLC
Phone: 903.245.6316
20108 CR 186
Flint, Texas 75762
Email: mevans@premiermagnesia.com
Acceptance:
_________________________________________________________
Laura Hill, Mayor Date
Attested By:
_________________________________________________________
Amy Shelley Date
City Secretary