15 October, 2003
In many ways the McMurdo community is like no other on earth. Its isolation and exposure to extreme temperatures and winds sets it apart from your typical small town. Access is limited—especially if the weather is like the past week’s and flights are cancelled. How is it then, that in this tiny community at the end of the earth I can still flip a switch and lights come on, turn the faucet and have a seemingly endless supply of clean fresh drinking water, and flush a toilet or pour water down the drain and know that it isn’t just pouring out onto the ground or straight into the bay adjacent to McMurdo? I set out in search of the answers to these questions, and visited the power, water treatment, and waste treatment facility.
The first stop on my utilities fact-finding tour was the power plant. Power Plant operator Dennis Nail met us in the control room. The plant went online 20 years ago and has 6 generators that run on diesel fuel. Three are enough to produce electricity for the base, so generators are used on a rotating basis, allowing plenty of opportunity for preventative maintenance and overhauls. Running such a facility requires plenty of fuel— approximately 1.3 million gallons of diesel is burned each year to produce the kilowatts we love. In the spring and summer they burn about 3300 gallons per day to produce around 1900kw of electricity. Since these generators are 20 years old, they are not exactly state-of-the-art models of efficiency. In fact, only about 1/3 of that diesel fuel that they use can be considered to be producing electricity. The other 2/3s of the fuel consumption is lost as waste heat and in heating the antifreeze that keeps it all from freezing. Now, the good news here is that much of the waste heat is captured and sent next door to the water treatment facility to heat the seawater as it enters the plant. Using the waste heat saves approximately 400,000 gallons of additional diesel each year that would be used to run a boiler that would heat the seawater. The good news is that there are plans in the works to upgrade the facility with new, more efficient generators. In the United States, if power is lost in one section of the grid it is common to draw from another section (unless you lived on the East Coast and Midwest during this summer’s power failure!). At McMurdo there are no alternative power plants from which to pull needed kilowatts. Instead, the town is divided into 6 sectors, based on priority, in case there is not enough power being produced. The power plant is, of course, the first priority (it takes power to make power). Second is the Crary Lab—don’t forget, this whole place exists to support science research. The dorms are last on the priority list. Some facilities have their own standby generators. This includes the firehouse, the NASA facility, the airfield, and the Crary Lab (don’t forget that science). At this point, alternative energy sources such as solar and wind are used only in the field camps. Dennis explained that it would be difficult to anticipate and react to the variability of such power sources with the current generators—they are difficult to start and stop on short notice if the plant were to attempt to blend power produced from a variable source with that produced by the generators. Perhaps with the new generators it will be easier to blend power produced from a variety of sources. One thing is for sure—it is all better than the small nuclear power plant that was used here in the early 1960s.
The next stop on this utilities tour was the water treatment plant. This plant was built in 1993 and was a vast improvement over the earlier plant that used a flash evaporation process. The current plant produces 80,000 gallons per day using a process known as reverse osmosis. Seawater is pumped into the plant and heated to 36F with the waste heat from the power plant. If it weren’t heated the fresh water that is produced would freeze, since the seawater comes in at 28F! The seawater is pressurized and pushed against a series of membranes within a filter. These membranes allow the water to pass through the filter, while trapping the salt. Without pressure, the natural movement of fluid would be from the fresh water to the salt to dilute the salty water. As the water moves through the plant it is pressurized even further to deliver it to McMurdo’s buildings. At the end of the tour plant manager Wendy Kober urged us to take long showers in the evening to take advantage of the water that had been produced that day. If she insists….
Last of all, we paid a visit to the wastewater treatment plant. As gray water and sewage enters the plant, it first must pass the ‘muffin monster’ a machine whose sole purpose is to break up all the chunks of stuff before it enters the aeration tanks. Once in the tanks, the mixture is aerated and mixed. After this the mixture enters a clarifier, a tank that allows the sludge to settle out and liquid to be drawn off for treatment. The sludge is run through the aeration tanks and a digester a few more times until all possible liquid has been drawn out. The remaining sludge is sent to a belt compressor where it is compressed into tidy blocks, dropped into triple wall crates and stored for shipping back to the US. Liquid that has been drawn off during this process passes by a series of UV filters as it exits the plant through a pipe to McMurdo Sound. Until last year, the plant was also sending the sludge into the ocean, but with recent upgrades, they are able to stick with the base’s policy of sending all solid waste back to the US for proper disposal. Right now there is a group of scientists diving in McMurdo Sound to study the impacts the sewage has had on the sea life and to determine how the system is reacting to the changes of the past year. I just find it amazing to know that such care is being taken to prevent pollution of the sound.
I suppose the end of this lesson on Penguin Power and Water is to question each reader to see if you know where and how your electricity is generated and where your water comes from. And where does it all go when you flush the toilet?
Seawater is for drinking
Ship your sewage home
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