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The Water Resource Recovery Facility is responsible for the effective collection, treatment and environmentally acceptable discharge of the wastewater generated by the Ann Arbor community as well as portions of Ann Arbor, Pittsfield and Scio townships. Wastewater Treatment Services is
responsible for the operation and maintenance of the City's wastewater treatment plant and eight sewage lift stations located around the city. Personnel are in attendance at all times, as the plant is a operation, 24 hours a day, seven days a week.
Don't treat toilets and drains as trash cans!
The primary function of the sewer system is to convey human wastes and water. The following products should never be flushed:
- Fats, Oils and Grease (FOG)
- Disposable wipes, rags and other rubbish
- Pharmaceuticals (prescription and non-prescription medicines)
- Household hazardous wastes: paints, solvents, insecticides, herbicides, etc.
We can take simple steps to help keep plumbing and sewer systems clear of clogs. "Flushable wipes" create blockages in household pipes and municipal sewer systems and should never be flushed down the toilet, nor should facial tissue or paper towels. Combined with fats, oil and greases, which should never be poured down the sink, these products can create enormous, and expensive to remove, "fatbergs".
Learn easy ways to help keep the Ann Arbor sewer system efficient and functional. Find out what not to flush, how to deal with fat, oil and greases, and how to prevent sewer pipe penetration.
Projects
Headworks Improvement Project
The headworks systems provide initial treatment to remove debris (screenings) and grit from the water as the first stage of treatment, which prevents damage to downstream equipment and systems. The existing headworks consists of three mechanical bar screens, three screw compactors and two grit removal systems including pumps, swirl separator and grit washer. The bar screens were installed in 1989 and in 2000 and require frequent repair and rebuilding. The grit system was also installed in 2000 and has required pump replacement and rebuilding of the swirl concentrators and washers over time. In addition, WWTP staff have observed significant accumulation of grit downstream of the removal system that indicates the efficiency of the grit system is significantly diminished and negatively impacts downstream equipment and systems. The cost and frequency for maintenance of the headworks have increased and parts for the screening systems are no longer available and must be custom fabricated. These systems are nearing the end of their useful life and are in need of replacement to ensure effective screenings and grit removal.
The Headworks Improvement Project includes replacement of the bar screens, grit removal equipment, screening and grit processing equipment, and installation of odor control improvements for the headworks buildings.
Spence Brothers of Ann Arbor, Michigan began construction in September of 2022. The new south screen and grit removal system are completed and in operation. The north screens have been installed and are in operations. The odor control building is expected to be completed and placed into service in April of 2024. The north grit removal system is expected to be completed and in service in June of 2024.
Ultraviolet (UV) Disinfection Replacement Project
The Water Resource Recovery Facility (WRRF) currently uses a Trojan UV4000 disinfection system to disinfect the WRRF’s final effluent. The current system has been in service since December 2000 and production of certain parts and maintenance items are being phased out by the manufacturer. In addition, the system has reached the end of its
useful life and must be replaced.
During the preliminary design and UV disinfection equipment selection, it became apparent that we need to construct an enclosure for the UV disinfection system, which was not included in the original design scope. The existing system is located below a metal canopy and is essentially exposed to the weather. Routine maintenance such as changing a bulb or replacing a ballast must be done despite the inclement weather. The new UV disinfection system will utilize sophisticated features, including touch screen controls, UV sensors, and a mechanical bulb wiping system. By enclosing the new UV disinfection system within a metal structure, we believe that we can increase the longevity of the new equipment and provide the highest level of safety for our employees.
Commercial Contracting Corporation of Auburn Hills, Michigan is expected to begin construction of the new UV Disinfection System in the Summer of 2024.
