Cloth filters: a support for pre-potabilization
We have seen that the potabilization phase requires the use of technologies such as reverse osmosis membranes and ultraviolet lamps: both of these technologies derive a great deal of support from the upstream installation of pile cloth media filters.
This is because the depth filtration, enabled by these solutions (instead of the translation of surface filtration), allows a higher yield of pre-potable solids removal. Each of the two downstream solutions achieves considerable advantages.
- Membranes are safeguarded from fouling. The frequency of chemical washes, which are periodically necessary for the proper operation of this solution but limited by good upstream filtration, is also limited.
- On the other hand, ultraviolet lamps require the water to be treated to have a very low content of suspended solids both for the sake of operating efficiency and difficult fouling management. Free-fiber cloth filters achieve this: up to 5 mg/l total suspended solids.