Spreading Manure

As usual, the La Conner Weekly News was “edutaining” last week. I was intrigued by a letter from Mr. Sather about where he might be able to pump his septic tank. As a past member of the county’s solid waste advisory committee, I can shed some light on the situation.

Cows have three stomachs, a very simple vegetarian diet and are a different species of mammal. These differences are significant enough to make the chances of disease and parasite transmission quite remote. The lagoons of cow manure are treated similarly to the sewage treatment plant at the edge of town. The manure lagoons are applied to the fields at agronomic rates, depending on laboratory analysis.

Sather’s septic tank has no such bells and whistles, unless of course it does, in which case the effluent could be used to water his lawn. I had a septic system that treated the “liquid” leaving the tank with ultra-violet light. The solids, however, had to go to a treatment plant to go through the “process to further reduce pathogens.”

Raw human sewage is what that caused the Black Plague. Our town’s sewage treatment plant is quite progressive in this regard. Our “solids” go through a thermophilic composting process that pasteurizes our waste, thus making it a wonderful addition to our soils. Some human pathogens are tougher than nails, but at temperatures of 140-160F most perish quite quickly.

Manure that gets applied to our soils has to go through a six month period before a root crop can be planted. Most of our manure gets applied to grass, corn, bulb and grain fields.

The anaerobic conditions in Sather’s cold dark septic tank allows for pathogens to lay dormant, not die. Building a compost pile big enough to thermophilically pasteurize his tankful of sludge would not be cheap – nor easy. It could be fun, however!

Putting the right mixture of things together and having it magically heat up to pasteurizing temperatures, well, that’s pretty cool. I think it should be taught in school by someone who isn’t a fool but might offer himself as a technological tool.

Glen S. Johnson

Skagit Valley