|
The methods of filtration used for water treatment vary greatly. Filtration includes all processes that mechanically separates a mixture of liquid and solid or dissolved substances into liquid (filtrate) and substances. The selection of the filtration process or multiple process steps is determined by the quality of the raw water and the requirements for the pure water (drinking or process water). The minimum size of the solids to be held back is defined via the separation limit of the filter.
Problem substances
The following, in particular, are problem substances in raw water:
- sand, solids, clouding substances and particles
- dissolved incrustations from pipelines
- iron, manganese and arsenic
- aggressive carbonic acid
- pesticides and chlorinated hydrocarbons (CHCs)
- impurities from circulation of water (e.g. condensate/steam cycle)
Special cases
Filtration via activated carbon (adsorption) and chemical deacidification are also classed as filtration processes.
Separation limits
This overview shows a rough correlation of the filtration processes and their use depending on the separation limits.
Filter systems
RWT dimensions, manufactures, supplies and installs high-quality and efficient systems for filtration, such as
- cartridge filters
- gravel filters / multi-layer filters
- filter units for iron removal, demangansiation and arsenic removal
- deacidification filters
- activated carbon filters
- membrane filtration units
Standard filter system
|
