Principles of biocides
Well, there is a whole world behind biocides. There are many different chemicals being used and working principles are quite different. Some chemicals will focus to attack the cell membrane of a micro-organism, others focus on stopping metabolic processes or block the replication process of micro-organisms. In some cases biocides will disable the possibility for micro-organisms to harvest energy, to run their metabolic processes. Altogether, different processes, with a different result.
Oxidative and Non-oxidative biocides
A big difference between working principles are so-called oxidative biocides (which usually focusses at blowing up the cell membrane and non-oxidative biocides. Oxidative can also be quite aggresive to the industrial asset and to our human health, working with these chemicals. Industrial assets such as cooling towers are still applying oxidative biocides, depended on legal frameworks and permits of a specific country, the asset recides in. A tendency for industrial assets such as geothermal wells, or upstream oil &gas is that non-oxidative biocides are most commonly used.
Microbial diversity
Another key thing is that the microbial world is diverse. And it is fair to say that diverse is an understatement. There are probably up to 1000 times more micro-organisms on our earth than what we can see as visible organisms (animals, humans, birds,..).
The effectiveness is highly depended the type of micro-organisms you need to deal with. Micro-organisms in general are flexible to adapt and withstand extreme conditions.
Conditions in the Asset
Also the kinetics are playing a significant role in the effectiveness. What is the concentration of a chemical and for how long is this functional concentration present?Is there a thick biofilm, are there high flow or stagnant conditions?
These elements will all influence the effectiveness of a biocide treatment. And even if you will test it beforehand in a laboratory, the real life situation could turn out quite differently. Due to the fact that microbial behaviour is difficult to capture in lab conditions, and only small differences can have a huge influence on the outcome.
AMPP standard TM21495
Experts from universities, and industry have gathered to develop a test standard to bring a next level of professionalism into biocide treatments. The initiative is brought into the former NACE standard framework, that has become AMPP. Document project manager of this initiative is Susmitha Purnima Kotu from DNV GL. The standard will primerly focus on the assesment of biocides through lab experiments. And will provide a clear guideline for methodological set-up of the experiment and proper methods to evaluate performance. Up to now, standards around biocide testing are hard to find and the bar for this standard development has been raised to accomodate both industrial and academic testing of biocides.
Susmitha Purnima Kotu DPM TM21495
We have invited her to tell you more about this initiative and the key elements that will be developed for this particular standard.
