Sodium Hypochlorite Shortage Affects Water Treatment

I ran into an interesting article over at BoombergLaw.com (thanks to Fred Gossen on LinkedIn for pointing at the article) about the problems that a number of water treatment and wastewater treatment plants are having with getting ahold of adequate supplies of commercial grade sodium hypochlorite for their water disinfection processes. Many have, according to the article, petitioned the EPA for legal assistance in acquiring the needed chemicals.

The article pins at least part of the blame for this chemical shortage on a fire at a chemical plant last year that shutdown a major supplier of hypochlorite and a pandemic driven increase in the use of family swimming pools. Both of these have undoubtedly had an affect the availability of sodium hypochlorite, but that is not the root cause of this problem. That can be traced back to the ‘inherently safer technology’ push away from using chlorine gas as a water treatment disinfectant back in the middle 2000’s (see one of my 2008 blog posts on the topic here). A fear of a large chlorine gas release in a major city because of an industrial accident or terrorist attack caused a number of environmental activists to successfully push many treatment facilities to switch to ‘safer alternatives’ and the easiest was from chlorine gas to commercial grade liquid bleach also known as sodium hypochlorite.

The big problem with bleach is that it degrades in quality (read – decreasing concentration while releasing chlorine gas) fairly quickly, limiting how far it can practically be shipped by rail. That, combined with the NIMBY opposition to the construction of new bleach production facilities, set up a tight supply situation for commercial grade bleach that left the market susceptible to production upsets. There are a number of alternative disinfection processes available, but they are almost all more technologically challenging with lengthy lead times and high switchover costs.

One potential long-term solution for larger facilities is the on-site generation of chlorine gas. The technology is well understood and requires water, salt (common NaCl), and electrical power as the major process feeds. It is still inherently safer than railcar loads of chlorine gas because it is produced as needed with relatively small amounts of process storage required. The biggest problem is getting rid of the byproduct sodium hydroxide (caustic soda). There are, however, lots of places that use that chemical as an important feedstock or process aid.