What's New

Mattabassett News

Baird was proud to serve as underwriter to The Mattabassett District on its $18.2 million bond offering.

• Learn more about the deal here: (Open and view PDF)

Cost Effective & Efficient

The Mattabassett District, the fifth largest facility in Connecticut, continues to be in the top ten in lowest costs per gallon of wastewater treated, and one of the most efficient.

SCADA

In 1992, the District was one of the first wastewater treatment plants in the northeast to install a Supervisory Control and Data Acquisition (SCADA) System with programmable logic controllers (PLCs) to monitor and control the treatment process. This enables one person on each shift to manage the entire facility from the control room and still have time to perform other tasks. One of the biggest benefits is that staff no longer walk several miles a day, just to turn equipment on and off. Operating the facility through SCADA is analogous to flying an airplane on auto-pilot. In July 2015, the SCADA system received an upgrade/expansion to be compatible with the Plant’s Nitrogen Upgrade.

Leading Technologies

The Mattabassett District maintains high standards of excellence in all areas and continually evaluates and installs the best available leading-edge technologies. A few of the many systems we are using are wet-packed tower odor scrubbing, biofiltration, carbon adsorption for incinerator mercury emissions control, and ultra-high efficiency filters for sub-micron particle removal from incinerator emissions.

In 2003, in response to Connecticut DEP nitrogen removal requirements, The Mattabassett District converted two empty aeration tanks into nitrification/denitrification treatment systems. This, and a number of process changes to our secondary treatment processes, resulted in successfully modifying a facility which was not originally designed to remove nitrogen into one that removes over 50% of the nitrogen entering the facility.

In February 2007, The Mattabassett District's new outfall – a 140-foot extension with 160 feet of 16 diffusers located in the deeper part (a depth of 20-plus feet) of the Connecticut River – went online. This has meant that The Mattabassett District's treated effluent discharge is no longer visible. Also, it mixes over a wider segment of the river and is more quickly assimilated.

In April 2007, The Mattabassett District's two new 1.5 megawatt emergency generators became operational. This means that, for the first time, The Mattabassett District can provide power to the entire facility if there is a power failure in the CL&P system. It also means that should the CL&P system be overtaxed and needs additional power, The Mattabassett District's power generators can be activated immediately and we can not only supply our own power, but can add an additional 1.4 megawatts to the grid.

In July 2015, the District completed a large expansion, the District Staff regained operation and maintenance of the entire upgraded facility. The upgrade increased the flow process capacity to 35 MGD. The main improvements included; a fluidizer bed incinerator with advanced emission controls, three highly efficient dewatering centrifuges, a side stream reactor for nitrogen removal, turbo air compressors for the aeration process, new odor control systems, upgrade/expansion to the plants SCADA system and more.

Between 2016 and 2023 the District completed many plant upgrade projects, safety improvement projects, and odor control projects.

A list of some of the major projects are:

2016-2023 Projects
Updated EH&S Plans
Odor Control Canopy over Septate & Sludge Unloading Facility
Odor Control Covers on headworks rags discharge falcility
Primary Tank Roll-Up Doors & Safety Improvements
Installation of Odor Perimeter Monitoring Units
Primary Tunnel Structural Improvements
Plant watermain replacement projects
Trunk Sewer Evaluation
Generator Controls Upgrades
On-Call Engineering Services
Air Compressor System Project
Temporary Flow Monitoring

In 2024 the District completed work on plant upgrade projects as well as odor control projects.

A list of projects that the District completed in 2024 are:

2024 Projects
Railroad Crossing Improvements
AC Compressor, valving, piping and abatement Admin bldg
Primary Tank skimmers (Tank 1) – Design & Construction
Primary Tank Skimmers (Tank 2) – Design
Headworks rags grinders - Design
Final Clarifiers (Center Column repairs, etc.)
Secondary Heat Exchanger Replacement
Carbon Replacement Incinerator
Outfall Cleaning
Trinnex Watercast Reporting software
Cone Valve Replacement No. 1
Meraki Network switch upgrade
Driveway and Pavement sealing, painting
Trunk Sewer lining - prelim design
Plant assessment Study
Culverts in ROW assessment and maintenance
Sludge storage blower motor replacement & energy rebate design
Odor control evaluation
Title V permit - Application Submission
Etter Engineering -Incinerator GasTrain Safety Improvements

In 2025 the District's capital improvements budget includes additional plant upgrade projects-as well as odor control projects:

2025 Projects
Primary Tank Skimmers (Tank 2)- Construction starting Fall 2025
Headworks rags grinders - Project on hold
Final Clarifiers (Center Column repairs, etc.)- Work underway
Incinerator Carbon Replacement - Completed April 2025
Outfall Cleaning - Fall 2025
Cone Valve Replacement No. 2 -Completed April 2025
Driveway and Pavement sealing, painting - Spring 2026
Trunk Sewer lining - Final design underway
Trunk Sewer lining Construction- Fall 2026
Plant assessment evaluation - Completed May 2025
Culverts in ROW repairs and improvements - Work completed Spring 2025, Phase 2 work underway.
Sludge storage blower motor replacement & energy rebate - project detrermined unfeasible at this time.
Guida's Dairy - BOD compliance improvements - Work underway

Odor control evaluation and improvement projects:

1. For a full list of odor control projects- Click Here
   
2. Evaluate and optimize odor treatment dosing for the Middletown Pump Station -Work on-going
   
3. Improvements and repairs to the Sludge Storage Bioway Sump - Work completed Summer 2025
   
4. Centrate Pump Station Upgrades- Design and contract bidding completed Summer 2025, Construction Fall
   
5. New Dewatering Building automated roll-up door- Design and bidding completed Spring 2025, door installed I Summer 2025, automation to be completed Fall 2025
   
6. Air flow balancing improvements for odor control treatment systems - Work completed Spring 2025
   
7. Headworks peroxide odor treatment dosing pilot test - Spring 2026
   
8. Dewatering Building chemical odor treatment system replacement evaluation - Evaluation underway

 

For additional projects scheduled for 2026, see the Capital & Major Projects page.