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Topics Issue 2 |
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Topics Issue 2 |
Are your closed water systems harbouring corrosion-inducing bacteria that nobody looks for?
For most closed systems it is assumed that there is very little oxygen present and therefore no need to test for bacteria or to treat with biocides. Nothing could be further from the truth says Sandra Emmons.
Many species of bacteria can survive under anaerobic (oxygen-free) conditions and some of these can increase the rate of corrosion in your closed water system, while also increasing your spending on corrosion inhibitor.
The main culprits are nitrite reducing bacteria (NRBs) and sulphate reducing bacteria (SRBs).
Most of us are familiar with the idea of bacteria living in water systems, with Legionella being perhaps the most notorious. Most of these bacteria are aerobic - they need oxygen to survive.
Anaerobic bacteria, however, have specialised in exploiting oxygen free conditions where they don't have to compete with the more numerous aerobic starins. To cope with this lifestyle, the anaerobes have developed ways of using the chemicals ariund them to provide nutrition and energy.
Of these anaerobic bacteria, NRBs and SRBs have the greatest potential to cause damage to closed water systems by increasing the rate of corrosion.
NRBs |
Nitrite reducing bacteria can reproduce rapidly and consume the corrosion inhibitor, preventing it from doing its job. The end result is a system that is at much greater risk from corrosion problems, combined with much higher bills for corrosion inhibitor.
The answer is to detect bacteria and apply the appropriate treatment. |
SRBs |
The action of sulphate reducing bacteria is more direct. By feeding on sulphates, the bacteria cause hydrogen sulphide to be released into the system, creating an acidic environment which is very aggressive to pipework. This can lead to severe pitting corrosion.
The answer is to detect bacteria and apply the appropriate treatment. |
As with other types of bacteria in water systems, the key to effective control is thorough and regular maintenance. Winning the war against anaerobic bacteria requires constant vigilance and this van only be achieved through a properly planned water treatment regime. Towerite is the specialist with the expertise to set our mind at rest.
