2008 - 2017 Capital Improvement Program

Project #8061, Metro Solids - Odor Control, Centrifuge, Sludge Storage

Description:

The project will replace the sludge collectors and pumps, and will cover six gravity thickener tanks at the Metro Plant and provide treatment for the odorous air using a biofilter. The gravity thickened sludge pumps will also be replaced under this project. The Metro Plant influent structures will be sealed. Odorous air from the Double Barrel Interceptor will be treated using the East Pretreatment Biofilter. This biofilter will be renovated.

Project Map

The project also includes the installation of an eighth centrifuge. This also includes require installation of another sludge feed pump, another polymer feed pump and the associated sludge and polymer feed piping. Space has been allocated for this additional dewatering equipment train. Sludge storage tanks will be rehabilitated. The sludge storage odor scrubber system will also be evaluated for possible upgrades or replacement. A sewer cleaning waste handling facility will be added to replace the Fifth and Kittson disposal site.

Purpose and Justification:

The odor control improvements project was initiated to reduce Metro Plant odors, hydrogen sulfide and the reductions of corresponding off-site impacts. The Metro Plant is required to be in compliance with hydrogen sulfide fence line limits by January, 2007. The need for the additional centrifuge is related to the rated capacity of the incinerators being increased, through performance testing, to 120 dry tons per day. This increased capacity significantly expands the periods when only two incinerators are required, but because there are limited options for feeding incinerators from given centrifuges, the increased incineration capacity places greater demands on the available centrifuges. This increased demand accelerates the wear and increases the centrifuge maintenance costs. Having an eighth centrifuge in the line-up increases the flexibility for assigning centrifuges to incinerators and improves overall system reliability.

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Project Authorization:

	Project Schedule		Authorizations
	Start	End	Funding	Status
Prelim. Engr.	Jan-04	Dec -05	$30,000	Approved
Design	Sep-05	Jan-07	$970,000	Approved
Construction	May-06	Dec-09	$21,000,000	Approved
Prior Authorization:			$10,600,000
2008 Budget Adjustment:			$11,400,000
Total 2008 Authorization:			$22,000,000
Future Authorizations:			$0
Total Project Cost:			$22,000,000

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Projected Cash Flow:

	Authorized	Future	Total
Prior to 2008	$7,958,000	$0	$7,958,000
2008 Budget	8,000,000	0	8,000,000
2009	6,000,000	0	6,000,000
2010	0	0	0
2011	0	0	0
2012	0	0	0
2013	0	0	0
2014	0	0	0
2015	0	0	0
2016	0	0	0
2017	0	0	0
Post-2017	0	0	0
Contingency	42,000	0	42,000
Totals	$22,000,000	$0	$22,000,000

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Impact on O&M Costs:

The construction of odor control equipment for the Metro Plant will require additional operation and maintenance costs. The estimated additional O&M costs for the odor control equipment is $10,000/year. The additional centrifuge should result in reduced maintenance costs and corresponding down time.

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Metropolitan Council

2008 - 2017 Capital Improvement Program