On-Site Chlorine Generation

Did you miss me? I’ve been battling a cold for over a week now, and it’s definitely cramping my style — including cutting down on my blog writing.

I just got this month’s copy of the American Water Works Association’s “Opflow” magazine, and found an article on on-site chlorine generation. You can find it at:


You can only access the full article if you are an AWWA member. And if you’re not a member, why aren’t you? You should all be members of our professional trade organization, as I have been for over 30 years. In fact, I’m now a proud Life Member!

Chlorine is the most widely used disinfectant in this country, as it has been for the past century. While chlorine has saved countless lives through the eradication of cholera, typhoid, dysentery, and other waterborne diseases, it has also posed severe safe handling concerns. In fact, at about the time that chlorine disinfection of water supplies began to proliferate in this country, chlorine was being used on the battlefields of Europe as a weapon of mass destruction. Chlorine in the gas form is nasty stuff — for microbes and humans alike.

Alternative chlorination chemicals like calcium hypochlorite granules and sodium hypochlorite bleach are used by many systems seeking to avoid the dangers of chlorine gas. These chemicals have some advantages and disadvantages when compared to chlorine gas, with the biggest advantage being greater chemical safety, and the biggest disadvantage being higher cost. The bleach has an additional problem in that it deteriorates fairly quickly, especially in heat and direct sunlight conditions.

In recent years, commercially-available systems to make sodium hypochlorite on-site have been developed. In general terms at least, I am a big fan. The only raw material that you need to purchase is salt. Nice, cheap, and easy to handle and store. This salt is converted into sodium hypochlorite by dissolving it in water — preferably soft water — and then applying electricity.

The higher electric bill is a concern, as is the cleaning of the electrodes in the unit. Hydrogen gas is also produced in the reaction, and it’s explosiveness presents another concern. Proper venting of this gas from the reactors and the storage tanks should easily mitigate this problem, however.

But the real advantage is that we are no longer filing Risk Management Plans with the Federal Bureau of Investigation — yes, the FBI! — because we are storing huge quantities of WMDs at our chlorination stations.

I think our customers — especially those near our existing chlorine facilities — would be big fans of this technology, too!

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