Silo Digester No.3 Mixing and Heating System - Design and Specifications

The City of Spokane is awarding a contract for the engineering design, specification, and associated services required to install a mixing and heating system in its existing Silo Digester No. 3 at the Riverside Park Water Reclamation Facility. The work includes detailed design deliverables (60 % and 90 % design sets, final Plans, Specifications & Estimates), permitting, construction phasing, utility coordination, bid support, and construction‑phase assistance. The design must accommodate limited site space, use a pumped mixing system similar to existing egg‑digesters, and employ tube‑in‑tube heating technology (excluding steam lances). The scope also requires consideration of future insulation/coating impacts on heating loads and must meet the City’s biosolids quality parameters. The contract term is two years with two optional six‑month extensions.