A project to upgrade equipment that supports King County’s effort to create energy from wastewater at South Treatment Plant in Renton might produce an occasional gas flare over the coming months.

The flare is not a cause for concern, said county officials.

The Wastewater Treatment Division is replacing four aging waste gas burners with three modern, more efficient units that are occasionally needed to safely dispose of surplus digester gas created as byproduct of the solids treatment process.

Until the installation of the new permanent units is completed in January, the utility will rely on two temporary outdoor burners that will be called into service when the digesters produce excess gas or process systems are offline for maintenance.

The temporary burners may produce a gas flare that could be visible from Southwest Grady Way or I-405 near the West Valley Highway, especially at night.

Most of South Plant’s digester gas is captured, processed, and either used for the cogeneration system that produces electricity and heat for the plant, or sold as natural gas to Puget Sound Energy.

The flare is part of normal plant operation and there is no need for the public to call 911.