To:
From:
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C. Motion:
Attachments:
Discussion:
City of Nashua, Public Works Division
Board of Public Works Meeting Date: October 26, 2017
Noelle Osborne, Plant Operations Supervisor
Wastewater Department
Digester Cleaning Project —-CO1
To approve change order 1 to the Digester Cleaning contract with Denali Water
Solutions in the amount of $48,400. Funding will be through: Department: 169
Wastewater; Fund: Wastewater; Account Category: 81 Building Improvements.
Change Order 1 Backup
The Primary and Secondary Digesters at the Nashua Wastewater Treatment
Facility are in need of cleaning. This is a large scale specialized project requiring
a contract with dewatering brought on site to perform this service over a 4-6 week
period. The project was bid in August and Denali Water Solutions was the low
bidder with a cost of $273,310.
In addition to dewatering the sludge, the Wastewater Facility and Denali have to
coordinate with Casella Organics on the transport and removal of the sludge.
Since the sludge removed from the process while the digester is being cleaned no
longer meets class B sludge, it cannot be land applied and has to be delivered to a
landfill owned by Casella. Casella and the landfill have required that odor control
measures be taken on the dewatered sludge. Casella will not transport or allow
sludge to be delivered to their landfill with strong odors.
A meeting was held recently with Casella and Denali during which Casella gave
specific recommendation on the odor control system to use. They recommended
the contractor use Remedia, a company with a propriety odor contro! chemical.
This company provides pumps, setup, chemicals and supervision as needed. The
contractor costs for odor control comes to $48,400.
