Knock out the bugs causing sewer corrosion by a spray — simple, cheap & effective
Lay summary by Mari Winkler
The rehabilitation of corroded sewer systems is a costly problem in our society and was estimated by the US Environmental Protection Agency to cost $3.2 billion in 2009. It is known that sulfide and sulfur oxidizing bacteria (SOB) proliferate in corrosion layers where they oxidize sulfur compounds, which results in sulfuric acid production, concrete corrosion, and leaking pipelines. In this study, it was shown in a long term experiment that spraying of free nitrous acid (FNA) on the concrete walls reduced SOB activity and appeared to be a promising strategy to reduce sulfide caused corrosion. Compared to previously reported methods for control of microbially induced concrete corrosion, there are multiple advantages for the FNA-based technology: 1) FNA has a long lasting effect in deactivating the SOB, 2) it is a cheap and easy technology compared to other spray methods, and 3) the method would use an environmentally friendly chemical (i.e. nitrite), which can be biologically removed in conventional wastewater treatment. The presented results form a new method to minimize corrosion risks, prolong the lifetime of sewer systems and hence costs associated with the replacement of damaged pipe systems.
For further information
Read the Water Research original research article which this summary is based on ‘A novel and simple treatment for control of sulfide induced sewer concrete corrosion using free nitrous acid’ (March 2015).
Visit the profile of the research ambassador, Mari-Karoliina Henriikka Winkler, who wrote this summary.
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