Sieve Analysis of Granular Filter Material
Granular filters used in water treatment often consist of one or more types of filter materials. The lifespan of these materials can vary significantly, depending on both the material type and the environmental conditions they are exposed to.
Sieve analysis of filter material is a useful tool that can be used both to assess the condition of filter material that has been in use over time, and for troubleshooting in cases where the filter, for example, has reduced production capacity or provides poorer water quality than expected.
We offer sieve analyses tailored to filter materials in water treatment plants. The sieve sizes we use are more varied and specific than those typically used in the construction industry, ensuring they are suitable for filter materials in water treatment processes. Filter materials that have been in use and in contact with coagulants often contain significant amounts of coagulant residues. These residues dissolve during drying and sieving, forming a coagulant dust that only occurs in used filter material. This dust can make up to 25% of the sample weight and can give a misleading picture of the particle size distribution.
In multimedia filters, we also often see mixing of the filter materials. In the report we provide, these factors are taken into account, allowing the sieve curves to be compared to the original state of the material. We also adjust the sieve curve to reflect the impact of any material mixing. Our report includes two types of sieve curves:
- Standard sieve curve: This can be compared with all sieve curves performed according to the standard NS-EN 933-1.
- Corrected sieve curve: This is adjusted to assess the condition of filter material in multimedia filters used in water treatment plants.
Depending on the purpose – whether it is to assess the condition of the filter material or to troubleshoot a filter – we provide recommendations on where the sieve samples should be taken from. We also offer assistance with interpreting the results if desired.
Feel free to contact us for more information.