If you have been out in the Big Woods during sub-freezing weather, you have surely seen the interesting ice formations covering some of the bushes. Old-timers know what produces the ice, but many newcomers find it puzzling. And if you haven’t seen the ice yet, it is worth venturing out for a look, especially on a cold but sunny day.

The basic story is this: the treated water from our waste treatment plant is sprayed out into the woods; and if the temperature is low enough, ice forms on the branches where the water hits.

Ice formations created by the sprinklers in our Big Woods.

It may strike you as odd that the water is sprayed into the woods, and you may wonder if that is normal. The answer is that it is normal for our operation and it is also used by a relatively small number of other treatment plants, most of them in our general region.

There are both pros and cons related to this method of disposing of the treated water (and perhaps that discussion will be the topic of a future blog post). The alternative (which most treatment plants use) is simply dumping the treated water into the nearest creek or river, where it ultimately flows out to the ocean. Our spray fields return most of the water to the groundwater aquifers that lie beneath our land, which is arguably a much better use of the water.

This spray field approach was very innovative when it was implemented 50 years ago, and there have been many visitors over the years that have come specifically to see how it works.

If you are interested in the details of how our treatment plant works (including the spray fields), check out this blog post.

Our treatment facility is showing its age, and parts of it (particularly the initial settlement pond, also known as the “Sequencing Batch Reactor”) are under consideration for an upgrade. At some point, changes to the spray fields may be considered, but for the near term you can expect to see the interesting ice formations each winter for years to come.