By: Sally O’Byrne, Teacher Naturalist
The Delaware Nature Society trip to the Veolia Wastewater Treatment Facility (Wilmington Wastewater Plant) on December 10 was not your usual natural history tour. However, learning a little about what happens to our wastewater, from toilets to dishwashers to industry to stormwater is probably good for all us waste-producing citizens to know about.
Water comes into the plant where it is strained, degritted, and clarified, using no chemicals in the process. Most of the work breaking down the organics is done by microbes, otherwise known as ‘bugs’; all sorts of ‘bugs’ that contribute to different parts and chapters of the cleaning. This gets a little complicated when the amount of waste water coming in changes every day, or every week, or every hour, and when accidental discharges of nasty things into the system disrupt the balance.
The ‘bugs’ need oxygen, so there are pipes aerating the tanks of wastewater to help the process along. Later in the process, the sludge goes into an anaerobic digester where the methane is collected to heat the ‘bugs’ so the process can start all over again. Other than the microbial ‘bugs’ the other living organisms present were gulls – lots of them, and by far the most common was Delaware’s own Larus delawarensis – the Ring-billed Gull.
For the final or tertiary stage, the now mostly clean water is pumped up the hill to very large settling ponds where there is further aeration and a final dose of chlorine before it is discharged into the Delaware River. These ponds are great places to find waterfowl in the winter, and today we saw many Northern Shovelers, Ruddy Ducks, Ring-necked Ducks, and American Coots. However, they were distant to us, even with the aid of a spotting scope.
The Wilmington Christmas Bird Count was yesterday and Jim White and I visited the same location, so stay tuned to see the report……….