I spent 4 1/2 hours saturday touring our town’s water system from both ends. It was quite a detailed tour and, since it involved chemicals, how could I not tag along?

We began with the sewer reclamation plant first. Lots of interesting details here. Turns out that one of the big problems to running a waste treatment plant has to do with keeping large debris out of the pumps- rags, underwear, shoes, plastic parts, etc.  Once you get past the shock of learning what your fellow citizens can and do flush down the toilet, it is plain to see that a bit of money spent on screening out the the big chunks is returned in the form of reduced down time and pump repair costs.

Our little hamlet of 6,000 souls sends 450,000 gallons of waste water to the reclamation plant on an average day. The flow peaks at about 8 am every day in the form of a sudden 5-6 x increase in flowrate. It takes about 90 minutes for an average volume (i.e., a flush) of wastewater to get to the plant. A lot of groggy citizens hop into the shower at around 6:30 am.

After the incoming stream passes through a grit removing station at the entrance, it is lifted to the first treatment operation for aeration and fermentation. This is the physical high point in the process, meaning that the stream is subsequently transferred by gravity for the remaining process steps.

I won’t go into further process details other than to say that the final step prior to discharge into the stream is a sanitizing step where the effluent is exposed to a large jolt of UV radiation. At this point in our tour, the plant manager dipped a sampler into the flow and withdrew one liter of clear, colorless liquid with a few strings of algae floaters. Only too eager demonstrate his faith that the water was sanitary, he dipped a finger into the effluent, put it into his mouth and exclaimed with a grin as wide as his mullet

“It don’t even taste like sewage!” 

As he passed the sample around so others could share in the experience, I wandered over to the control panel and feigned interest in the LCD display. The UV just renders the wee beasties non-viable. Their little microbial carcasses are still there. Pathogen free it may well be, I didn’t have the stomach to taste it. Yes, I know that microbes are everywhere and that our notions of what constitutes “clean” are merely a fantasy. But I just couldn’t do it.

Advertisements