Ever wonder what happens at the other end of the pipe? You know, after you’ve released the water from your sink, flushed it down your toilet, drained your tub, watched it disappear down a floor drain, or heard your washing machine rocking and rolling as it empties itself out. I suspect that most folks don’t give it much thought, especially those that have septic tanks in their backyards. After all, whatever takes place there, happens underground and out of sight and most are fine with leaving it at that. They say “goodbye” and hope it’s final!
However, for folks in homes and businesses connected to a wastewater treatment facility things are different. They say “goodbye” to their water as it enters the pipe and someone else says “hello” to that same water as it emerges from the other end of the pipe, after what is often a long and dark journey.
Immediately upon emerging from the pipe and into the light of day, your used water is now referred to as wastewater and will need to receive proper treatment before it can be safely released back into the environment. Wastewater treatment plant operators utilize systems comprised of pipes, tanks, valves, pumps, blowers, chemicals, and control systems to ensure that proper treatment occurs. The physical arrangement and size of these system components were designed by an engineer and can all be seen and touched. However, the most important components of proper wastewater treatment cannot be seen. To the naked eye they are invisible, yet they do the lion’s share of the work. They are the micro-organisms often referred to as “bugs”! But, I’m getting ahead of myself.
The first step in the process of treating wastewater is similar in a way to trashpaddling as it involves removing things that don’t belong in the water in the first place: plastic, wood, paper, metal, rocks, sand, etc. Many operators find themselves continually amazed at what some people think is an appropriate disposal method for their trash. At this point, the water having done its job of conveying waste to the facility is fast losing its freshness and is beginning to decompose.
Now, getting back to the “bugs”, they originate in the wastewater, actually in our guts, and once out and on the loose they’re looking for food and a good time! What happens when they find that food is critical in determining whether pleasant or unpleasant conditions will result. If decomposition is allowed to happen naturally, the “bugs” will quickly use up the available oxygen as they consume any food they are exposed to. When the available oxygen is gone, the process will continue without oxygen and will produce unpleasant results such as odors and gases. Think belching, flatulence, and flies! However, if an adequate supply of oxygen can be provided to the bugs, they will do their work in an aerobic environment and no unpleasant odors or gases will result. It is the operator’s job to see that this herd of “bugs” remains happy, fit as a fiddle, hungry and busy making more “bugs”! This is done by providing them with their favorite levels of oxygen, pH, temperature, nutrients, and of course, food. In a way, we operators are similar to shepherds in needing to take good care of our respective flocks. It is this element of harnessing ‘Mother Nature’ in a good way that has always intrigued me.
Once the “bugs” have eaten their fill they’re allowed to settle “fat and happy” to the bottom of a tank and provided time to digest and take care of other business. When hungry again, they’re provided another banquet and so on, and so on. The resulting clear water (aka supernatant), from which they settled out of, is disinfected and released back into the water environment.
Now entering my fourth decade of treating various wastewaters from various sources, I pause today to reflect on their differences in origin and treatment. In the 1980’s I worked in treating wastewater that had originated on the campus of a boarding school. Following treatment, that water was released back into the Assabet River watershed. There, I first learned about the unseen and largely undocumented “bug” workforce!
During the first half of the 1990’s I treated wastewater from a high tech office campus that was ultimately released into the Beaver Brook/Stony Brook watershed. The second half of the 1990’s and first half of the 00s found me treating contaminated water that was being retrieved from below ground, remediated and released into the Aberjona River watershed. Instead of using “bugs”, this site utilized “breakpoint chlorination” to oxidize urea ammonia nitrogen and the incredible properties of activated carbon to remove unwanted chemical compounds from the water. This site was also unusual in that it consisted of 50 acres of land surrounded by an 8 foot high fence designed to keep people out. Within this fenced enclosure, I had numerous encounters with wildlife such as coyotes, deer, rabbits, great-horned owls, red-tailed hawks, fishers, foxes, minks, musquashes, herons and ducks. I also learned much about the relationships between surface water & groundwater and above ground topography versus below ground topography. The site also contained an “ephemeral stream”…first I’d ever heard that term used for a stream and liked the way it sounded! Today, this same site is on the “superfund” list and because of underground topography is affecting an area much larger than the original 50 acres.
During the latter half of the 00s, while working for a contract operations firm, I treated wastewater from another boarding school (Sudbury River watershed), a shopping plaza (Merrimack River watershed), and condominium (Nashoba Brook/Assabet River watershed) and was back to working with my buds, the “bugs”.
Near the end of the 00s, now working as a freelancer, I began treating wastewater that had been used in the manufacturing of food products. The first of these was from the making of frozen desserts (aka ice cream). Here the name of the game is pretreatment which means treating the water only to the point where it is acceptable to another wastewater treatment facility for ultimate disposal into Boston Harbor. Because this wastewater has such a high level of oxygen demand, the “bugs” face a daunting task and need to be supplemented with the nutrient urea ammonia in order to perform their task adequately. Yes, that’s right…at one location I worked to remove urea ammonia nitrogen while at this one, I add it!
Recently, I’ve begun treating another food product manufacturing wastewater. This time it is from the making of seafood products and is also a situation where a wastewater having an unusually strong oxygen demand is pretreated to the point where it is acceptable to another treatment plant. Following its further treatment there, it is released into Massachusetts Bay. In an odd way, it seems that I’m home at last! Sort of like the “Cheers” episode in which Norm landed the job in the beer brewery. You see, I love seafood the way that Norm loves beer!:) Overcome with emotion, he hugged the nearest tank and cried “I’m home”!
My plan is to continue freelancing in the wastewater treatment field and include other water related tasks such as collecting representative samples of surface and groundwater as well as performing inspections of treated wastewater release locations (aka outfalls) for owners of same.
If things go as planned my business logo will be a variation on the “We’re the Birds to Call” one that has been in my family for many years. For my purposes, “I’m the Bird to Call” spoken by the perched vulture should suffice…
Hopefully soon, the ice will melt and my boat and I will, once again, be plying our local waters!