2018-2020 Anaerobic Digestion Improvements

 
The Lucas County Board of Commissioners signed an agreement with Quasar Energy Group for improvements to the anaerobic digestion process at the Water Resource Recovery Facility (WRRF).  The improvements will allow the WRRF to become more energy independent through cogeneration of electricity while producing a higher quality of bio-solids (from Class B to Class A) for reuse.

 

The improvements include refurbishing the existing four digesters; construction of a dual purpose building for receiving and dewatering solids; construction and installation of the necessary tanks and heating equipment to produce Class A bio-solids; installation of two one-megawatt generators; installation of two new centrifuges for solids dewatering and construction of an arched roof system to cover the bio-solids storage pad.

2015 Facility Name Changed

 
In June 2015, the Lucas County Board of Commissioners changed the name of the Facility to the Lucas County Water Resource Recovery Facility (WRRF) to more accurately reflect the operations and purpose of the facility.

2010 Dewatering Centrifuge Improvements

 
In 2010, the MRWWTP included improvements with the selection, purchase, and installation of a new centrifuge for dewatering digested sludge. Lucas County received financing and grants for the installation of the new dewatering centrifuge and completed the project in 2010.

The installation of the new centrifuge was adjacent to the belt filter press, where it was used with a truck loading conveyor. The belt filter press was retained as backup dewatering equipment in the event the centrifuge is out of operation for service or repair.

2003-2005 Plant Expansion 

In 2003-2004, the Maumee River WWTP was expanded again to increase the design / peak capacity by 7.5/17.3 MGD (Plant total is now 22.0/47.3 mgd). These improvements were constructed as a totally separate liquid treatment train called the West Plant. The former Plant B is now called the East Plant.

The West Plant treatment includes influent screening and grit removal for preliminary treatment, a primary clarifier, chemical addition for phosphorus removal, two two-pass aeration basins for activated sludge treatment, two final clarifiers, and an ultraviolet disinfection system. The new West Plant was constructed with the future capability to be expanded to a design/peak capacity of 15.0/34.5 MGD.

In addition to the construction of the new West Plant, the County also made several improvements to the East Plant, the Anaerobic Digesters, Sludge Storage Facilities, and the Administration Building. The improvements to the East Plant included replacing the old centrifugal blowers with new, energy-efficient single-vane centrifugal blowers; replacing the coarse bubble diffusers in the aeration tanks with fine bubble diffusers; replacing the old chlorination/de-chlorination system with an Ultraviolet Disinfection system; and, installing bio-scrubbers for odor control at the aerated grit chamber and raw sewage pumping station. The other changes to the MRWWTP included increasing the Anaerobic Digester gas line sizes, adding an additional dewatered sludge storage pad, and adding new offices, conference rooms, and storage space in the Administration Building. 

1994-1996 Plant Improvements

 
In 1994, the Maumee River WWTP underwent construction to upgrade the Plant B portion of the wastewater plant and return its treatment capacity to 15 MGD. These improvements included replacing the original influent comminutors with filter screens, adding three primary clarifiers, a third final clarifier, effluent dechlorination, anaerobic digestion, and an electric cogeneration facility using digester gas.

The cogeneration system is designed to use the digester gas (or natural gas) for fuel in two engine driven electrical generators. After these improvements were complete, the MRWWTP abandoned the sludge thickening tanks and the aerobic digesters. 

1984 Solids Treatment Improvements

 
In 1984, the MRWWTP underwent some process changes to improve the dewatering process that also reduced the treatment capacity of the facility. These changes included removing the Zimpro wet air oxidization system and the vacuum filter, converting the Plant A aeration tanks to aerobic digestion tanks, and installing a new two-meter belt filter press.

These changes resulted in the loss of five MGD of treatment capacity and 12.5 MGD of hydraulic capacity, but greatly improved the efficiency of the solids treatment process. 

1978-1980 Plant Expansion 

In April 1975, planning was completed for expansion of the MRWWTP treatment capacity. The plant expansion called for the construction of a second set of treatment facilities capable of processing 10 MGD.

The second new plant, referred to as Plant B, consisted of an aerated grit tank, a raw sewage pumping station, and head tower, chemical addition for phosphorus removal, eight aeration tanks for activated sludge treatment, two final clarifiers, and a chlorine contact tank. Plant B began full operation in May 1980 with a 21.5 MGD hydraulic capacity. This raised the total design / hydraulic capacity of the MRWWTP to 15/34 MGD.