6/30/15
Mattabassett District Celebrates Completion of Incinerator Upgrades
By NEWEA, Melissa Hamkins, and Brian Armet

On June 24th, NEWEA’s Plant Operations Committee in conjunction with the Connecticut Water Pollution Abatement Association conducted a facility tour and technical presentation at The Mattabassett District Water Pollution Control Facility.  A technical presentation highlighted the recent upgrades at the Facility, including:

• 4-stage Bardenpho nitrogen removal process (2 new & 4 renovated aeration tanks)
• Sidestream reactor for centrate nitrogen removal
• 3 Westfalia centrifuges replacing 3 belt filter presses
• New state-of-the-art 1.5 dt/hr fluidized bed incinerator with state-of-the-artemissions control
• Expansion from 20 mgd to 35 mgd
• 60 mgd effluent pumping station and 6 mgd effluent reuse pumping station
• 7 carbon canister odor control systems
• Updated SCADA & Updated Asset Management System
• Numerous other improvements and upgrades

Melissa Hamkins (Wright-Pierce) and Brian Armet (Mattabassett District) describe the overall project and its context:

With sewage sludge incinerators (SSIs) permitted in 14 New England locations, incineration of wastewater treatment biosolids is a significant method of biosolids disposal in New England.  EPA’s new source performance standards and emissions guidelines for new and existing sewage sludge incinerators is having an impact on sludge handling as facilities with incinerators investigate how to meet these new limits and whether they will continue to operate their SSI(s), install new incinerators, or get out of the incineration business.  This is true not only for the wastewater treatment plants which have SSIs, but also for the many facilities which send their wastewater solids to merchant incineration facilities in New England. 

The Mattabassett District started design on a new Fluidized Bed Incinerator (FBI) in early 2009 as part of an overall Wastewater Treatment Plant upgrade design project.  The design made provisions for keeping the existing FBI in service to be used as a backup once the new FBI system was operational.  The District had made modifications to their existing FBI system to address lower allowable mercury emissions by first piloting an activated carbon mercury removal system and then incorporating the pilot system into their on-going operations.

On September 30, 2010, EPA proposed new source performance standards and emissions guidelines for new and existing sewage sludge incinerators.  After a comment period, these standards were finalized on February 21, 2011. (See past NEBRA coverage of these new regulations here and here.)

The new regulations were published during the ongoing design of Mattabassett's new incinerator system.  Even though the original incinerator design was incorporating a high level of emissions control to allow easy acceptance as Best Available Control Technology by regulators, the new rules required changes to the design of the system. The new rules also prompted changes to how the existing system could be handled in the future.  Now, with the completed upgrades in place and permitted, Mattabassett is ready and able to meet the March 2016 compliance deadline required by the new EPA standards.