3.6. SR 06-28-1999
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**Item 3.6.**
River
MEMORANDUM
TO:
Pat Klaers
City Administrator
FROM:
Darrell Mack
WWTF Superintendent
DATE:
June 22, 1999
SUBJECT: Emergency Power Supply For Lift Stations
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Mter meeting with utilities manager Bryan Adams, it appears that in a major power
outage the utilities generating facility will be able to supply power to the wastewater
treatment facility. The generating facility would not be able to supply power to any
lift stations except on a four hour rotation, which is not often enough to prevent
sewage backups. To keep the collection system from backing into homes we need four
additional generators. Three generators would be set up at stations that cannot be
down for any length of time and one generator would be used to keep the rest of our
stations pumped down. The following quotes were received with Ziegler Power
Systems being the lowest:
Ziegler Power Systems $57,430
Katolight $59,300
Cummins North Central $64,118.40
Long Lake Tractor $90,210
(price does not include sales tax)
Used
New
New
New
Even with Ziegler quoting used generators, I feel they are a best buy for a couple of
reasons:
1) they have been checked out and repairs were made if they were
needed,
2) they are set up for all 3 voltages that we have in Elk River, which
makes them a lot more versatile and can be used at other locations.
The other generators that were quoted can be wired for all 3 voltages, but at an
additional cost.
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Because no single generator is over $25,000, we do not have to go through the bid
process. Therefore, it is my recommendation to purchase the generators quoted by
Ziegler Power Systems.
13065 Orono Parkway. P.O. Box 490 · Elk River, MN 55330. TDD & Phone: (612) 441-7420. Fax: (612) 441-7425
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1:11< River MEMORANDUM
TO: Patrick Klaers, City Administrator
FROM: Terry Maurer, City Engineer 4'
DATE: June 28,1999
SUBJECT: Clarifier Failure at Waste Water
Treatment Plant
This memo is a follow-up to Darrell Mack's memo dated June 14, 1999,
regarding the primary clarifier failure at the Waste Water Treatment Plant.
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As Darrell accurately points out in his memo, the treatment plant is designed
for a capacity of 1.6 MGD, and the city's current average flow is just over .760
MGD. What Darrell's memo does not clearly state is that to handle the
current flow, the city's Waste Water Treatment Plant relies on two primary
clarifiers. With one clarifier out of service, the other one is overloaded during
certain periods of the day. Clearly, if the plant flow was at a 1.6 MGD
design, it would be overloaded 24 hours per day. Currently it is overloaded
(according to Darrell's memo) for 16 hours out of a 24 hour period.
One other issue I would like to point out is that summer is historically the
higher flow season of the year. We can expect the flow at the Waste Water
Treatment Plant to increase during the summer, and with the number of
projects coming on line, it will increase even more.
Based on these facts, I would recommend that the city deal with this clarifier
failure as an emergency situation, and have new equipment installed as
quickly as possible. If you have any questions regarding this issue, please
feel free to contact me.
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13065 Orono Parkway · P.O. Box 490. Elk River, MN 55330. TDD & Phone: (612) 441-7420. Fax: (612) 441-7425
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City of ~'
Ell{ River
TO:
MEMORANDUM
Lori Johnson
Finance Directo~ J .AJ1'1
Darrell Mack~P" I
WWTF Superintendent
FROM:
DATE:
June 14, 1999
SUBJECT: Primary Clarifier Failure
As you know, our #1 Primary Clarifier Drive has failed and needs to be replaced
ASAP. There are two reasons why we need to start the replacement process as soon
as possible. First, our present plant capacity is 1.6 MGD and our average daily flow
is .760 MGD in a 24-hour period, so during our peak flow period from 7:00 a.m. to
1:00 a.m., our #2 primary is overloaded which may cause permit violations due to low
detention time. This does not allow adequate time for the solids to settle. Second,
under the best conditions it will take three or four months to get the parts and have
them installed. With our rapid growth, the longer it takes to fix this problem, our
chances of permit violations will increase.
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13065 Orono Parkway · P.O. Box 490. Elk River, MN 55330. TDD & Phone: (612) 441-7420. Fax: (612) 441-7425
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