734.794.6450Screw Pump Replacement Project
The WRRF utilizes five screw pumps to lift sewage at our Raw Sewage Lift Station to begin the treatment process at our Headworks and three screw pumps to lift water at our Equalization and Retention Building. As a result of the inspection of the existing screw pumps in the summer of 2024, it was evident that screw pumps #1, 2 and 3 at the Raw Sewage Lift Station and the screw pumps #6, 7 & 8 at the Equalization and Retention Building were in poor condition and required replacement. In addition, the corresponding slide gates required repair or replacement.
The replacement of the six screw pumps and corresponding slide gates is vital to plant operations and essential in maintaining our compliance with our NPDES permit.
Process Piping & Equipment, Inc. of Howell, Michigan will begin demolition of two screw pumps at the Raw Sewage Lift Station on or around Monday, April 6, 2026. Unfortunately, this work may result in a short term increase in plant odors and will generate some noise. This work is in preparation for the new screw pump installation in the Fall of 2026. The new screw pumps are expected to be completed by early 2027.
Odor Control System for Solids Handling Building Truck Loading
An odor study for the Ann Arbor Water Resource Recovery Facility (WRRF) area was performed in 2018 and 2019 by HDR, Michigan, Inc. (HDR) to address ongoing nuisance odor complaints from WRRF neighbors. The odor study included review and evaluation of available data for the WRRF and surrounding area, sample collection and analysis of air samples from potential odor sources, assessment of the effectiveness of the WRRF existing odor control systems, air dispersion modeling to assess how odors may migrate within the study area based on geographical and climatic conditions and an objective assessment of where odors are likely to exist at nuisance levels.
The HDR report identified two areas at the WRRF that potentially cause offsite nuisance odors under certain meteorological circumstances. These locations include the Screen and Grit Building and the Solids Handling Building’s truck loading area. A new odor control system was designed and construction and was placed into service in 2024 as part of the Headworks Improvement Project.
The design and Installation of an odor control system for the Solids Handling Building’s truck loading area is included in the City’s Capital Improvement Plan (CIP) beginning in FY 26. The WRRF currently thickens and centrirfuges the waste activated sludge before it is loaded into trucks and disposed of at a landfill.
OHM Advisors (OHM) of Livonia, Michigan has begun the design phase of this project.
Equalization and Retention Building Rooftop Solar and Battery Storage System
The Office of Sustainability and Innovations has worked in recent years to implement behind the meter renewable energy systems at City facilities. One of these facilities is the WRRF, where staff are planning for a rooftop solar and battery storage system. The project involves mounting 1400 photovoltaic modules on the roof of the equalization and retention building, which will provide up to 480 kW of AC power to the facility. In addition to the solar, the system will include 250 kW of battery storage. This storage system will be able to reduce the peak demand of the facility which should provide significant cost savings to the plant. This system is slated to begin construction by the summer of 2026.
