The facilities Master Plan was completed in 2004 and identified the need for improvements to the City of Ann Arbor’s Wastewater Treatment Plant (WWTP). The renovations include rehabilitating existing structures, upgrading of primary and secondary wastewater treatment processes and replacing aging facilities with new facilities. These renovations will allow the City of Ann Arbor to meet future flow and loading demands as well as regulatory requirements. The current WWTP has a design capacity of 29.5 million gallons per day (MGD), and consists of an older West Plant (constructed in the 1930’s) and a newer East Plant (constructed in the late 1970’s).
The City of Ann Arbor retained Malcolm Pirnie, an international environmental firm that specializes in the study, design and construction management of WWTP, to design the improvements. The Facilities Renovations Project was split into a Phase I project and a Phase II project. Phase I includes the design and construction services for the demolition of two existing structures. Phase II is the larger of the two projects and includes the rehabilitation of the East Plant and the demolition and reconstruction of the West Plant. Both phases are summarized below.
Facilities Renovations Project - Phase I
Phase I of the Facilities Renovations Project includes:
- Demolition of the Storage Building.
- Demolition of the Reaeration Tank.
- Relocation of utilities prior to demolition.
- Electrical work to isolate the East Plant power from the Solids Handling Building.
- The installation of a waste activated sludge line to convey sludge to the Solids Handling Building.
The Storage Building is located directly to the west of the Solids Handling Building and the Reareation Tank is located to the south of the Solids Handling Building. The early demolition of these facilities will provided additional staging area and traffic patterns for the Residuals Handling Project. Live utilities currently run through the Storage Building and as such, must be relocated prior to demolition of the building.
Phase I – Status – The Storage Building Demolition and Improvements Project was substantially complete as of November 2009. The following is a summary of the major events:
· The 100% drawings and specification were submitted to the WWTP in August 2007.
· The drawings, specifications and permit application were submitted to the MDEQ in November 2007 and the MDEQ Part 41 Construction Permit was issued on February 20, 2008.
· The MDEQ issued a Part 31 Floodplain Permit on April 30, 2008 and the Ann Arbor Township Planning Commission gave conditional approval of the Site Plan Review on May 7, 2008.
· The City of Ann Arbor issued a Notice to Proceed to Sorensen Gross Construction Services, L.L.C. for the work associated with the estimated 8 month Phase I project on January 27, 2009.
· As of November 2009, the project is substantially complete.
· Punch list was issued on November 5, 2009 and updated on November 23, 2009 which identified work items required for completion of the project.
· Change Order No. 1 was executed by the City and Sorensen Gross Construction Company and including a 39-day extension.
· Change Order No. 2 was executed by the City and Sorensen Gross Construction Company.
· Final completion of the project is anticipated in the fourth quarter of 2010.
Facilities Renovations Project – Phase II
Phase II of the Facilities Renovations Project includes the majority of the work and includes the following elements:
· Field investigation phase that included
o Pre-demolition survey of hazardous and other waste materials
o Concrete repair survey
o Access bridge survey
o Secondary clarifier equipment evaluation
o Ferric chloride storage and feed system evaluation
o East Plant biosolids sedimentation survey
o Administration Building evaluation
o Plant isolation gate evaluation
o Geotechnical investigations
o One-line verification
o PICs field wiring survey
· Design Phase
This phase of the project can be separated into the East Plant Modifications, West Plant Demolition and Reconstruction, and electrical and site work.
East Plant Modifications includes:
o Rehabilitation of the East Plant Aeration system including the new blowers, new air piping, new diffused aeration system, new mixers and reconfiguration of the tank flow patterns
o Modification of the East Electrical/Blower Building including: removal of the standby generators and electrical gear, a new sampler room is being designed within this Building and the replacement of RAS pumps
o Electrical improvements to the East Primary Building
o Miscellaneous repairs to the Secondary Clarifiers
o Conversion and rehabilitation of the Dechlorination Building to Tertiary Filter Blower Building.
o Construction of the East Ferric Building
o Concrete repair and gate repair throughout the East Plant
West Plant Demolition includes:
o The demolition of the six digester tanks, primary and secondary clarifiers and aeration tanks, administration building, a portion of the old chlorine contact tank, chlorine building, flow splitting structure, sulfur dioxide building, fabrication shop, machinery and west blower building and the old flocculation basins.
West Plant Reconstruction includes the design and construction of:
o Primary clarifiers
o West Primary building
o Aeration tanks
o Secondary clarifiers
o West Secondary Building
o Administration Building
o An electrical building for the Raw Sewage Lift Station
o An Influent Splitter/Flow Monitoring Station
o West Ferric Building
The electrical and site work includes:
o Replacement of the existing 4800 KV power distribution system with a 13.2 KV power distribution system
o Central Electrical Building
o Replacement of the existing standby generators with new generators located within the Central Electrical Building
o Re-routing of existing site utilities
o Reconfiguration of the existing storm water system
o Upgrading the existing earthen embankment so that it meets FEMA standards and can be certified
o Relocation of DTE power transmission lines
o Installation of new roadways throughout the plant
o Upgrading the existing SCADA system
Phase II – Status
The design of the Phase II Project is ongoing. The following is a timeline of the key project milestones, to date:
· The 60% design was submitted to Ann Arbor in September 2008
· The 90% design documents were submitted to Ann Arbor for review on December 14, 2009.
· A 90% design review workshop is scheduled for March 18, 2010 to review the project status.
· It is anticipated that the 100% design will be completed in the second quarter of 2010.
Moving parallel with the design is the final site plan application process through Ann Arbor Township and Washtenaw County. The following is a timeline of the key site plan milestones, to date:
· The application for review and approval of the Preliminary Site Plan and Natural Features Impact Statement was submitted to Ann Arbor Township on November 18, 2009.
· A Natural Features Setback Use Permit public hearing was held during the Ann Arbor Township Planning Commission meeting on December 7, 2009.
· The preliminary Stormwater Management Plan was approved by the Washtenaw County Water Resource Commissioner on March 1, 2010.
· The Preliminary Site Plan application and Natural Features Impact Statement were approved during the Ann Arbor Township Planning Commission meeting on March 1, 2010.
In addition, FEMA Conditional Letter of Map Revision (CLOMR) application was submitted to FEMA on March 26, 2010. FEMA Administrative review comments were received on May 13, 2010. It is anticipated that the response to their comments will be submitted to FEMA by the end of July 2010. After FEMA receives the necessary supplemental information, the 90 day technical review period will commence.
For more information on this project, please contact
Mike Amicangelo at MAmicangelo@A2gov.org