Project No. 25502

Project Start Date: Fall 2023

Estimated Completion Date: TBD

Project Manager: Brian Stone 703-737-7120

Project Description:  During the last two decades the solids treatment process has remained relatively unchanged. However, water usage has been declining due to conservation and low-flow fixtures which causes an increase in solids concentrations of sanitary sewer flow. The Town's solids processing facilities have been impacted and a biosolids capacity analysis is underway to evaluate current system treatment capacities.

The study will recommend near- and long-term process expansions and technology upgrades. This multi-year project includes engineering design and construction for replacement or upgrade of existing infrastructure (four anaerobic digester domes - two constructed in 1970, one in 1987, and one in 1994), solids capacities expansions, odor control, electrical substation B upgrades and other treatment technology enhancements identified to ensure regulatory requirements are met. The Water Pollution Control Facility Odor Control & Biofilter Media Replacement (25504) and the remaining phases of the Water Pollution Control Facility Storage Tanks - Re-coating & Rehabilitation (18002) were consolidated into this project.

Project Updates:  In May 2025, the Town’s engineering consultant submitted the 30% design documents for the solids processing improvements project. The project includes three new gravity thickeners, electrical load center, improvements to the digestion facilities, and associated sitework and subsurface linear utilities. The bid-ready design documents should be completed by summer 2026 with an advertisement for construction bid to follow. Staff anticipates the bids will be received in fall 2026.