Design/Construction Considerations for Subarctic Wastewater Plant

In 1983, CH2M HILL was named design/construction manager for a $35‐million project to expand Anchorage's wastewater treatment plant. The project will double the size of the Anchorage Water and Wastewater Utility's existing primary treatment plant to 2005 design year flows of 54 mgd $(2.4m^3/s)$ average day, and 128 mgd $(5.6m^3/s)$ maximum day. Significant design and construction considerations include stabilizing a bluff against erosion by ice and other forces; installing a new outfall diffuser in upper Cook Inlet; maximizing construction efficiency by minimizing impacts from darkness, cold, and winter storms; providing a system to economically heat sludge thickeners and primary clarifier scum boxes; protecting clarifiers during their first winter; and extending a multifunction utilidor system. Construction of the new diffuser is expected to be complete by September 1987. The project is expected to be complete, with the expanded plant in full operation, by early 1988.