Backflow Protection For Drinking Water
Julius Ballanco, PE
This year, my hometown of Munster, Ind., celebrated its 100th anniversary. My wife and I have been residents of the town for a good number of those years. It has been a great community to raise our three children.
For part of the centennial celebration, the town sponsored tours of some of the local industrial buildings. My wife and I immediately signed up for the tour of the Pepsi bottling plant. I have driven by the Pepsi plant countless times over the past 20 years, but could never get inside the building. The Pepsi plant was always a top-secret operation, or at least that is what we locals thought.
It is understandable why Pepsi doesn’t open its plant for tours. The biggest concern for companies like Pepsi is industrial espionage. If it were nice to the public and provided tours, someone could jump on the line and try to steal all the corporate secrets. Of course, this time Pepsi knew that the people taking the tour were just curious local residents wondering what goes on in the plant.
Because I have been involved with many town activities, I had an idea of what was going on at the Pepsi plant. It is one of the largest bottling plants in the Midwest. There are multiple bottling lines.
The most fascinating were the bottled water lines. There were two bottled water lines operating the day we took our tour. Each line bottled 800 bottles a minute. You read that right, 800 bottles a minute!
That means with the two lines operating, there were 1,600 bottles a minute of bottled water. Multiple that by 60 minutes, 24 hours, and you have a lot of bottled water coming out of the plant each day. The last I read, the bottled water business does in excess of $10 billion a year in sales, with the two largest bottled water companies being Coke and Pepsi.
Getting back to the bottled water, I asked our tour guide a number of questions. I already knew that the drinking water in Munster came from Lake Michigan. That meant the bottled water at the Pepsi plant also originated from Lake Michigan.
I asked, nonchalantly, what they did to the water prior to bottling it. He explained that the water went through two filter systems and then was injected with ozone. However, he explained that by the time you open the bottle of water in the store, the ozone is gone from the water.
So Munster water, from Lake Michigan, is filtered twice, treated with ozone and bottled for your drinking pleasure. By the way, Lake Michigan water is wonderful water and a great source for bottled water.
Still Need Backflow: The big question from the plumbing industry is, “Does the plant have a backflow preventer on the water supply to the bottling lines?” The answer is, “Of course they do.” Bottled water plants still must have protection of the potable water supply with the installation of a backflow preventer.
This seems strange to some in the profession. Why protect the water supply from a process that is supplying bottled water to the consumer to drink? Basically, we don’t take any chances. As it turns out, the same water supply is used to produce carbonated beverages. So, protection is required because of the backflow potential.
In the Pepsi plant, as with similar plants, there are numerous cross-connections. Pepsi does a great job of making sure the possible cross-connections do not contaminate the bottled water. But, the possibility exists and Pepsi constantly runs quality control checks to make sure no contaminated beverage makes its way to the consumer. Its quality control center was impressive.
If there is an occurrence, the company can prevent the sale of a contaminated product, but without a backflow preventer, it cannot assure that the water main does not get contaminated. Therefore, Pepsi and the other bottling plants need a backflow preventer.
There are other operations that use only water. The water is cleaned beyond the level of the drinking water coming out of your faucet. The water may be deionized water, also called DI water, or ultra-pure water. You may ask, why provide a backflow preventer for these water systems?
Again, the answer is simple. Look at what is located downstream of the high-quality water. In many cases, there are cross-connections in the process. While the user may not consider them cross-connections, the plumbing industry knows that they are.
Another problem with high-purity water is that if there is a reversal of flow, high-purity water can play havoc with the piping system. Water that is super-purified will pick up the piping material in the walls of the pipe, tube or fittings. This can lead to high concentrations of a contaminant. The water in contact with the piping system also can result in the premature failure of the piping system by corrosion or degradation.
I once had an incident with a DI water system that was completely contaminated. The DI water was dispensed in a two-story laboratory through special faucets. The faucets allowed the technicians to connect a rubber hose from the faucet to the experiment. One experiment went awry and contaminated the entire DI water system.
If this DI water system did not have backflow protection, the entire potable water system would have been contaminated. The laboratory also realized that there was justification for having adequate backflow protection at each DI faucet. It realized that an upgrade in equipment was far less expensive than the cost it paid to clean the DI water system.
So, even water may need backflow protection if you are going to do something to that water. Just a reminder to be vigilant when evaluating a water piping system.