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Access Schedule

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PROJECT MANAGER CONTACT

Contact Main Office

PROJECT LOCATION

Tigard, OR

BID CLOSE DATE

2025.10.30

PROJECT DESCRIPTION

Furnish all labor, materials, and equipment necessary to:
a. Construct and commission a new 1.3-million gallon, cast-in-place concrete, anaerobic digester with a vertical mixer mixing system (new digester).
b. Install and commission new digester support systems including, but not limited to, a new spiral heat exchanger, hot water pump and piping, digester sludge recirculation pump and
piping, grinder, and associated control valves. Install and commission new redundant digester sludge recirculation pumps for the existing Digester Complex 2 (DC2) digesters
1 and 2.
c. Construct digester gas system improvements including, but not limited to, new digester
pressure relief and vacuum valves, foam separator, moisture separator, gas flow meter,
isolation valves and piping associated with the new digester.
d. Construct a new access bridge from the DC2 control building to the new digester.
e. Modify the existing DC2 digesters, including, but not limited to, adding fall protection tie
off anchors at roof access hatches, access modifications to the digester overflow box, replacement of existing overflow isolation slide gates with new knife gates, and
installation of new digester gas isolation valves.
f. Construct improvements to the Digester Complex 1 (DC1) flare including, but not limited
to, a new modulating waste gas burner (WGB) bypass valve, new regulator, new WGB electronic controller, new spark generator and panel, a new uninterruptible power supply,
and new exposed and buried digester gas piping.

g. Install and commission new actuated valves for the digester feed to DC1 and DC2 in the
basement of the Solids Building.
h. Install and commission a new Fats, Oils, and Grease (FOG) feed train to the new digester including a progressive cavity feed pump, flow meter, control valve, and piping from the Brown Grease Receiving Facility.
i. Install and commission two new high-efficiency, condensing natural gas boilers, boiler
loop pumps, associated hot water system piping, and valve modifications.
j. Remove and replace the primary and secondary hot water system pumps, including
associated hot water piping system modifications.
k. Install and commission a new hot water recirculation pump for the FOG offloading screen non-potable water hot water system.
l. Demolish the existing DC 2 electrical room air handling unit and condenser. Install and commission a new air handling unit and condenser and upsize the supply and return ductwork.
m. Site improvements including, but not limited to, a new decant facility, site lighting, drainage improvements, irrigation sleeves, topsoil and compost, asphalt roadways and
curb and gutter improvements.
n. New motor control center, electrical panelboards, transformers, instrumentation, and associated conduits and conductors.
o. Upgrades to the existing electrical, instrumentation and Supervisory Control and Data Acquisition systems necessary (equipment replacement or improvements) to support the
modifications.
p. Furnish and install related equipment, temporary items and systems, and other appurtenances necessary to complete the Work and to provide a complete and functional
system in accordance with the Contract Documents.

Available Project Information

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