THE CITY OF NASHUA othe Gere Cy"
Dyriston of Public Works
Wrastenuater 1 Jepeartntent
DATE: December 12, 2017
TO: Lisa Fauteux, Director of Public Works
Carolyn O'Connor, Finance Manager
FROM: Noelle Osborne, Plant Operations Supervisor, Wastewater
RE: Digester Facility Boiler System Emergency PO Request
During routine maintenance to the Digester Facility
Boiler systems a diaphragm failure was discovered in the
expansion tanks. This failure caused over pressurization
of the system, resulting in a mechanical seal Lallure in
a water recirculation pump, damage to the expansion
tanks, as well as damage to the water separation tank.
This failure is believed to be caused by the inconsistent
quality of the methane gas produced by the digester. The
current Energy Recovery Generator replacement project,
which is in preliminary design, is already addressing
this issue with gas purifying equipment.
We are requesting an emergency purchase order on these
critical components for three reasons. First, the
boilers are used to heat the digester and are critical to
the operation and maintenance of the optimal temperature
of the solids in the digester. Second, the ordering lead
time on some of the needed units is 4-6 weeks. Further,
with the digester currently offline, it is an ideal time
to take care of these repairs.
We are requesting an emergency PO be issued to in the
amount of $43,571 to cover the cost of the work.
Please contact me if you have any further questions.
¢ Sawmill Road * Nashua, New Hampshire 03060 # Phone (603) 589-3560 « Fax (603) 589-3474
