SOUTH VALLEY, ABQ--I finally thought of a place to take my grandson that was just as exciting as The Garden of Broken Glass
that we visited 6 months ago: The Sewage Treatment Plant! Run by the Water Utility Authority and known as the Southside Water Reclamation Plant
, the facility is located on 2nd St. SW along the Rio Grande. This site was picked for a reason. Gravity and excrement, as any former APS employee can tell you, are partners in the flowchart of life. And the far south valley is the lowest point in Bernalillo County.
I called Sharon Sivinski of the WUA
to give Robby and me a tour. Tours are normally done for classrooms 4th grade and up, but I told her I was writing a story about the place and Robby was more than my 9-year-old grandson, he was my angle
We met Ms. Sivinski at a picnic table near the big water tower. She gave us an overview, showed us a chart, and handed out shiny blue hardhats. We took off for the building that housed the Bar Screens.
The Bar Screens are like giant combs that all incoming liquid flows through. They pick up everything they catch and dump it on conveyor belts that take the stuff to trucks bound for the landfill. What we saw on the belts were mostly plastic items and goo that must have been held together by some kind of plastic or latex. Whatever. There was
a big Bar Screen story, however, that made our jaws drop and our eyes go big.
One day an employee spotted an iguana on the conveyor belt, along with all the other stuff. The employee rescued the small lizard and took it home. It is now the size of the picnic table we sat around earlier. Everyone figures it must have been dumped in a clean-out somewhere not too far from the sewage plant. I forgot to ask the iguana's name. It might have been something like Lucky, Stinky, or Dirty Harry.
Skimming Off the Bio-Diesel
Next the liquid waste goes to the Grit Chamber where stuff like sand, grit, coffee grounds, and egg shells settle out. This is also taken away for disposal. Now if you aren't doing your own composting and you are putting this stuff down the garbage disposal, just think about it. There have to be at least 200,000 households here feeding perfectly good composting materials directly into the sewer system where it has to be separated out and thrown away. A small fraction of it might end up in the WUA compost facility and spread on west mesa ranch land or city parks, but most of it just ends up in the landfill.
A Little Clarification
The Primary Clarification Tank in the last "filter" before the bacteria get to work. In these tanks sludge settles out and is removed from the bottom and a long arm goes around the top of the circular tank and skims off the oil and grease. Yes, your Extra Virgin Olive Oil is just as much a bother as the greasy dishwater from Hurricane's. It all is removed in the same way. At this point it is landfill bound, but the WUA is working with a private company to turn the stuff into bio-diesel fuel. Presumably the bio-diesel could be used to run the WUA's own fleet of trucks.
My favorite part of the sewage treatment plant has to be the Aeration Basins. There are actually two types: anoxic and oxic. Some kinds of bacteria work better without oxygen and some like all the oxygen they can get. The oxic tank just foams and bubbles as air in fed into the brew to help the bacteria grow big and strong. The bacteria eat the waste and denitrify the ammonia (largely from urine) releasing nitrogen gas. The bottom of the oxic tanks are covered with hundreds of air-emitting stones like you would find in the bottom of an aquarium...only these are the size of pancakes from the Flying Star.
After eating themselves into microbial oblivion, the fat, old bacteria settle to the bottom in the Final Clarification Tank. This is stuff is now what is called sludge and ends up in the Digester. The Digesters are kept at 98.6 degrees so that the micro-organisms can create the environment necessary to make methane gas. The methane is sent to
the CoGen Facility which burns the methane making electricity to run the plant. The CoGen facility accounts for roughly 70% of the electricity used at the site. What is left in the digesters is hauled off to the landfill.
The Big River
Meanwhile, the water coming out of the Final Clarification Tank is sent to a chlorine treatment vat. Some of this chlorinated water is filtered through four feet of sand and reused by the treatment plant and the city.
The rest is treated with sulphur dioxide to dechlorinate the water. The chlorine is used to disinfect the water, and the sulphur dioxide is used to remove the chlorine. Then the water is released into the Rio Grande.
You can see the effluent from the sewage plant is a different color than the brown river. Lots of carp live there. I'm not sure why, since the water has nothing alive left in it when it is discharged. But then, maybe eating dead stuff is what they do best.
It is also interesting that this effluent from the waste water treatment plant is considered to be a major tributary of the Rio Grande. It varies with the seasons, but it is always rated in the top 10.
Through the Microscope
My grandson Robby had enough of all this walking around and was ready for lunch. After all the sounds, sights, and smells of this excursion, he was ready to eat. Well, there was one more stop, and it turned out to be his favorite thing of the day: looking at sludge through a microscope
Sharon fixed up a sample of the liquid from the aeration basin and invited Robby to take a look. Wow! There were bristle worms, stalked ciliates, carnivorous free-swimming ciliates, amoebas, and several other kinds of micro-organisms all eating the bacteria that ate the solids.
We also saw a red blood cell in there.
It makes you think about what else gets flushed into the sewer. Sometimes I worry about all the medicine that ends up being flushed down the toilets all over town. Who knows what chemicals like that do over long periods of time. I am sure that some of them will be around in our rivers and oceans forever.
• 55,000,000 gallons of liquid waste are treated here each day. The plant has the capacity for 110 million.
• No bacteria or other micro-organisms are added to the waste. Instead, existing micro-organisms are fed lots of oxygen so they multiply and eat heartily.
• TEACHERS: Classroom tours are available...as are school visits by educators. Tours are for 4th graders and up. In-class presentations cover grades 1-12.
• Egrets like to hang out on the clarifiers.
• Generating electricity takes a lot of water--about 1/2 gallon per kilowatt...primarily for cooling.
• Industrial users (like Intel) must pre-treat their sewage before they send it to the WUA.
• This is an interesting and timely field for people looking for a career.