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West Point Treatment Plant Phase 2 Digestion System
Name: West Point Treatment Plant Phase 2 Digestion System
Location: Seattle, WA
Status: Completed
Type: Waste Water Treatment Plants
Owner: King County
Engineer: Carollo
The West Point Treatment Plant Phase 2 Digestion System project involved mechanical, electrical, instrumentation and control system upgrades to improve the wastewater solids digestion system. The work included installation of: a digester feed preheat loop and heat exchanger; digester feed flow meters; digester liquid level sensors; Digester 4 and 5 gas flow transmitters; grinders; and valves and actuators to enable Digester 6 to be used as an active digester. Improvements were located all over the West Point Treatment Plant. Some mechanical and piping work involved connections into 'live' digested sludge lines. Construction was performed during specific, short timeframes while the solids system was taken out of service to minimize the risk of system upset. The work also included extensive modifications to the hardware and software of existing operational Programmable Logic Controllers (PLCs) and digester gas piping systems on Digesters 4 and 5. Digester gas constituents are primarily methane (approximately 55%) and carbon dioxide (approximately 40%).