Donohue & Associates and Western Lake Superior Sanitary District (District) received a 2023 ACEC Minnesota Engineering Excellence Honor Award for the Oxygen Supply Improvements Project (OSIP) at the water resource recovery facility. The project team worked closely with District personnel to develop a solution that was cost effective, reliable, and energy efficient.
The District’s water resource recovery facility uses a High Purity Oxygen (HPO) biological treatment system. Prior to this project, oxygen for the HPO system was generated by two cryogenic oxygen production systems commissioned in 1978. These aging systems were energy-intensive and nearing the end of their reliable service lives.
The Donohue team provided equipment assessments, cost opinions, and qualitative and quantitative analyses that facilitated a decision-making process for the next generation oxygen production system. The solution, a new 80-ton-per-day Vacuum Pressure Swing Adsorption (VPSA) system, is the first VPSA system producing oxygen for an HPO facility in the upper Midwest.
The new system requires relatively little operator interaction and District personnel are able to perform routine maintenance activities previously outsourced. Annual estimated maintenance cost savings are over $100,000. Other advantages include a compact footprint, mechanical simplicity, and mechanical redundancy.
In addition to the oxygen production system improvements, Donohue also designed a complex electrical switchgear and distribution system upgrade.
Donohue led planning and implementation, providing design and project management for process, structural, electrical, control systems, HVAC-mechanical, and civil engineering services as well as construction administration/observation and O&M services including programming, startup, and training.
Since startup, the facility has been achieving excellent effluent water quality. Energy savings realized are significant; this project and others have helped the District avoid $1M of annual energy spending compared to 2013.