This scope consisted of front-end engineering and detailed design to increase the bark firing capacity of an existing combination boiler at a paper mill. Initial studies identified issues, and the project team proceeded with FEED package development. The project scope included a new bark feed conveyor, an upgraded bark storage bin, new stokers, a multi-level over-fire air system, an improved bottom ash handling system, a full electrostatic precipitator rebuild, and a modulating selective non-catalytic reduction (SNCR) system for NOx control. The final FEED package included the technical deliverables to define the scope as well as a class 3 estimate, level 2 schedule, and a recommended path forward for final client decision. The project team continued to be involved as the client conducted detailed engineering, construction, and start-up.