Ion exchanger fish odour
In some situations, an ion exchanger can emit a specific fishy or fish-like odour. It is therefore said that the ion exchanger stinks or that the ion exchanger gives off a smell reminiscent of fish. The fish odour occurs especially with the strongly basic anion exchanger type 1 in the OH form. The odor is usually trimethylamine C3H9N, an organic gas and component of the functional group of anion exchangers, which is washed out, the so-called hoffmann amino effect. The odour is to be regarded as production-related contamination. The odour occurs both in the ion exchanger resin bed itself and in the product produced after the ion exchanger, e.g. in demineralized water from a demineralization system, circulation water from an ion exchanger system and possibly also in the waste water in a chemical-physical waste water system if a strongly basic anion exchanger is installed as a selective exchanger.
The fishy smell is perceptible even in the smallest quantities and is generally perceived as unpleasant. There are health risks in higher concentrations. A 30L ion exchanger can be sufficient to make the odour perceptible in an entire factory hall.
What measures can be taken against the fish odour of ion exchangers?
- The strong fishy odour of the ion exchanger, especially strongly alkaline anion exchangers, is only significantly reduced to the residual odour typical of ion exchangers that have been subjected to a special chemical cleaning process, known as the removal of production-related impurities. The resin is emptied from the big bag or from the bags and chemically pre-cleaned in batches within the scope of the ion exchanger regeneration service. It is then drained of residual water and repacked ready for transport for the use on site. When in use, the product of the ion exchanger, i.e. the demineralized water, is then no longer contaminated by the fish odour.
- The fish odour also disappears by itself over the operating time of the ion exchanger, but is released into the process flow, i.e. the product from the ion exchanger, e.g. the generated demineralized water or circulation water. However, indirect discharge of wastewater contaminated with trimethylamine into the municipal sewerage system is generally not permitted due to local drainage statutes or the model statutes of the DWA (German Association for Water Management). This also applies to ion exchanger breakage, so-called ion exchanger sludge or grit (broken ion exchanger resin balls), which must not enter the sewerage system.
Are you planning to use a strongly alkaline anion exchanger, are you using a smelly ion exchanger or would you like to have the production-related impurities removed in advance? Please also note our further information on the ion exchanger and what you need to bear in mind.
Please contact us if you have any further questions.
