TD keeping a lid on it

Our favorite Barber Mike Nagle captured this gem On Monday, Feb. 17 on First Street in The Dalles.

The Dalles, Ore., Feb. 19, 2025 — This will aid digestion.

The Dalles sewer treatment plant is in the process of getting some much needed maintenance at its biosolids digester which utilizes bacteria to break down all the goodies in sewage.

The upshot? A safer, cleaner environment for all of us in The Dalle and protection of the Columbia River which is used by 26 downstream communities.

A company out of Boise, Idaho was contracted to do the work which includes refurbishing the lid of the digester and the interior of the tank which is kept air tight as that magical bacteria does its work to breakdown human waste.

The process in a sewage digester is called anaerobic digestion, where bacteria break down organic matter in the absence of oxygen, producing biogas as a byproduct.  Anaerobic digestion can significantly reduce the count of harmful pathogenic bacteria in sewage sludge.

Its pretty important as the City of The Dalles deals with about 2.5 million gallons of sewage per day before it goes into the Columbia River.

As you could imagine, sewage and human waste is corrosive, meaning it has molecules made of one hydrogen atom and one oxygen atom that are negatively charged. Called hydroxide ions or (OH-), the molecules promote the formation of hydrogen gas on the surface of a metal, which can then readily penetrate the metal lattice, leading to a phenomenon called "hydrogen embrittlement" that weakens the metal and causes corrosion.

So, after several years in operation, maintenance is necessary to reline the tanks and lids to keep the digester safe and operable.